Iusmhistology - User contributions [en]

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Admin — Wed, 23 Feb 2011 18:13:19 GMT

Admin:

===Exam 2===
*[[Bone and cartilage]] (02/21-23/2011)
*[[GI - Glands]] (02/16/2011, )
*[[GI - Small intestine through anus]] (02/14/2011, Williams)
*[[GI - Mouth through stomach]] (02/09/2011, Williams)

===Exam 1===
*[[exam_1_flashcards.txt]] (tdf)
*[[20110131_10_respiratory_notes]]
*[[20110126_07_lymphoid_organs_notes]]
*[[20110124_06_connective_cells_notes]]
*[[20110119_05_connective_tissue_notes]]
*[[20110112_04_circulatory_notes.txt]]
*[[20110110_03_epithelium_notes.txt]]
*[[20110105_02_nervous_notes.txt]]
*[[20110103_01_muscle_notes.txt]]

Bone

Admin — Wed, 23 Feb 2011 18:08:18 GMT

Admin: moved Bone to Bone and cartilage

#REDIRECT [[Bone and cartilage]]

Bone and cartilage

Admin — Wed, 23 Feb 2011 18:08:18 GMT

Admin: moved Bone to Bone and cartilage

*started here on 02/21/11 at 1PM.

==Bone and Cartilage==
*Starting a series of three lectures: today, Wednesday (development), and Monday (metabolic regulation).
*Chronic musculoskeletal issues are huge!

===Evaluating bone health in the clinical setting===
*Most important diagnostic is bone density imaging.
**DXA = dual energy xray a?
**We have a huge reference population on which to base our results.
**Disadvantages:
*High resolution CT scanners
**Pretty and pretty amazing
**Becoming more common

*Serum / urine biomarkers:
**These are markers that can help us know how much osteoblast and osteoclast activity and bone resorption activity.
**Go back to this list after the lecture.
**Don't need to know all of these

*Bone biopsy
**Take a coring tool, core out some from the iliac crest.
**Then take a histological slide.
**Not used very much.
**Used when biomarkers just don't tell you what you need to know.
**However, histology is very important for clinical trials

===Bone cells===

====Osteoclasts====
*Large
*Multiple nuclei
**More nuclei = more metabolically active
*Much larger than any surrounding cells
*Originate from hematopoietic lineage
**HSC sits in a macrophage CFU in the bone marrow
**Become monocites
**Stay in bone marrow
**Become osteoclast
**Rank ligand essential for diff into preosteoclast and full osteoclast.
*Rank ligand
**Made by osteoblasts
**Made by other cells of the bone marrow.
**Attaches to rank receptor on pre-osteoblasts
*Multiple osteoclasts fuse to form multinucleate
*OPG
**A decoy receptors for rank ligand
**Can keep osteoclasts from developing by sucking up all the rank ligand
*After maturation and getting to bone surface it starts to resorb bone
*Sealing zone is generated to attach firmly to the bone
**Allows the osteoclast to target where resorption will occur
**Compartmentalizes the enzymes
**Generates a "focal zone"
*Ruffled boarder is generated
**Increases the amount of surface area so enzymes can be pumped out of the cell onto the bone in high amounts.
*Enzymes for resorption:
**TRAP
***Tartrate-resistant alkaline phosphatase
***Can be assessed in blood to know how much activity of osteoclasts is occurring
**Cathepsin K
*Houshets lacuna
**Well in bone where resorption has occurred.

===Osteoblast===
*Located on bone surface
*Secrete osteoid
**Osteoid is unmineralized
*Osteoid ges minieralized eventually.
*Come from mesenchymal cells
**Need runks2 and ostrix
**Without you get no bone
*Runks2
*Ostrix
*Alkaline phosphatase is key protein involved in matrix production
*Osteoblasts become: osteocytes, bone lining cells, or it can undergo apoptosis.
*Osteoblasts secrete osteoid until their signal to secrete goes away then it beocmes one of thse three fates.
*Bone lining cells:
**Flattened
**Lay on bone surface
**Can still become activated
**In a nomral state, these cells line the entire bone.
**Signal can cause them to plump back up and resume bone formation.

===Osteocyte===
*Most abundant of cells of the bone
*Third cell within bone
*Impt for sensing signals within the bone
*These are terminally differentiated
*Surrounded by osteoid or mineralized matrix.
*MOst abundant of bone cells
*Connected to each other and to the bone surface by filopodial processes
**These live in channels called canaliculi
**Connected via gap junctions.
*There is one osteocyte per lacunae.
*Perform matrix maintenance and mechanics.
*This is an intricate network of osteocytes
**Trading nutrients
**Sending information

====Genetic profile differs from osteoblasts====
*Osteocyte cannot produce any more matrix
*Has different functions than the osteoblast
*Don't memorize the table
*Sclerostin is a gene unique to osteocytes and not osteoblasts.
**This shows up in late an osteocytes differentiation.
**It inhibits bone formation
**We are trying to develop drugs to inhibit sclerostin help grow bone.

===Bone matrix===
*Made of type 1 collagen.
**A fibrous collagen.
*Takes on a staggered arrangement.
**Mineral connects them end to end.
*The fibrils are highly crosslinked
**Promotes structural rigidity.
*Mineral interspersed also adds rigidity.
*Fragments of crosslinks can be used to measure bone turn over.
*C-propeptide in the blood means there is bone formation
When does collagen get cleaved?
*Collagen is formed in a twisted plywood formation.
**This gives strength to the bone.
**So its like people and they it is twisted in an orientation that will maximixe the structural integrity.

*Non-collagenous components:
**Know osteopontin, osteonectin, and ostecalcin
**Osteocalcin is a biomarker that can be measured in the blood to know how much osteoblast activity (bone formation) there is.

*Bone mineral
**Mineral goes between adjacent collagen fibers and in the space between.
**As it accumulates it first goes between length wise.

===Tyeps of bone tissue===

====Woven bone====
*AKA primary bone and Immature bone
*Not very common in the adult skeleton
*Found only when there is a bone injury or in some pathological state
*This is the type of bone that is formed when you need bone right now.
**Provides rapid stabiliation
*Not very organized
*Osteoid spit out in all directions
*Relatively low mechanical strength.

====Lamellar bone====
*AKA secondary bone, mature bone
*Most of the bone oin our bodies is this type
*Highly organized
**As mentioned above
*Formed slowly
*Higher mecanical strength than primary.
*Lamellae:
**Differing patterns of collagen organization
**Result in high birefringence
***The ability to refract light differently.
**This is a product of the alternating pattern of collagen fibers.

===Bone anatomy===
*Cortical or cancellous bone
**Cortical is called compact
***This is the outer part
***Main fxn is structural
***PRovide resistance to loading
**Cancellous bone = spongy bone = trabecular
***NOT squishy
***Small piece of cancellous and small piece of cortical would looke the same.
*Four different surfaces:
**Outer surface is called the periosteal surface
**Within are the cancellous surfaces
**Endocortical surface is the inside of the cortical surface.
**Within cortical bone are the haversion units.
**KNow the four surfaces

====Haversion systems====
*AKA osteons
*An osteon is a unit of bone that the osteoclasts have dug out and then replaced within the cortical unit of the bone.
*Within the haversion system is a space where the blood vessels and nerves flow.
*The center part of this '''haversiona canal''' is the ''central canal''.
**Run along the long axis of the bone
*Perferating canals = volkman (?) canals
**Go perpendicular to the long axis of the bone
**House vessels and nerves
*OUter edge of osteon is called the cement line.

====Periosteum====
*This layer is tightly adherent to the bone
*Both cellular and fibrous layers

====Endosteum====
*Endosteum is similar to periosteum but is on the inside of the bone
**Endostium '''has only cells'''.

===Structures===

====Lamellae====
*Concentric lamellae:
**These are concentric.
**Each ring from the outside of the bone in are called lamellae.
**Associated with a central canal.
*External circumferential lamellae**WRap all the way around the bone.
*Interstitail lamellae
**Within the bone tissue but not associated with central canals

==Cartilage==
*Cells are housed in lacunae which are surrounded by matrix.

===Hyline cartilage===
*Found in joints, respiratory passages, ends of ribs, within bones
*Made of type 2 collagen fibrils
*Has some non-collageneous proteins proteoglycan aggregates.
*Proteoglycan aggregates
**Have a central core
**Have some protein cores and then glycoaminoglycans hanging off.
*PG attract water and can therefore act as a shock absorber.

*Chondronectin
**Holds cells in place on the collagen and proteoglycans

*Condrocytes:
**Retain mitotic activity
***Unlike osteoclasts
**Can form 2, 4 or even more cells within its region.
**These units are called isogenous groups.

*Hyline matrix:
**It is not uniform.
**Terirtorial matrix = capsular
***Found just around a chondrocyte
***Capsule is found closer
**INterteritorial matrix
***Found farther out.
**The collagen fibrils are smaller in the territorial matrix
**The types of pg are different in the territorial than interterritorial.

*Perichondrium
**Fibrous tissue that lines the outside of hyline cartilage in most but not all locations of hyline cartilage
**Allows connection of muscle to cartilage
**Supplies the cells that can differentiate into chondroblasts (which diff into chondrocytes)

===Fibrocartilage===
*Found mostly in IV disks
*Has type 1 collagen in it.
**Forms fibers called rows or chords
*Between chords are the chondrocytes
*Has no perichondrium
*Can serve as a transition between tissues like tendon and bone.

===Elastic cartilage===
*Found in the ear, epiglottis, and the larynx
*Has type 2 collagen
**Fibrils
*Elastic fibers also present
*Has a pericondrium
*Looks much like hyline but you can see fibers in it.

*stopped here on 02/21/11 at 3PM

Main Page

Admin — Wed, 16 Feb 2011 18:17:42 GMT

Admin:

===Exam 2===
*[[GI - Glands]] (02/16/2011, )
*[[GI - Small intestine through anus]] (02/14/2011, Williams)
*[[GI - Mouth through stomach]] (02/09/2011, Williams)

===Exam 1===
*[[exam_1_flashcards.txt]] (tdf)
*[[20110131_10_respiratory_notes]]
*[[20110126_07_lymphoid_organs_notes]]
*[[20110124_06_connective_cells_notes]]
*[[20110119_05_connective_tissue_notes]]
*[[20110112_04_circulatory_notes.txt]]
*[[20110110_03_epithelium_notes.txt]]
*[[20110105_02_nervous_notes.txt]]
*[[20110103_01_muscle_notes.txt]]

GI

Admin — Wed, 16 Feb 2011 18:16:50 GMT

Admin: moved GI to GI - Mouth through stomach

#REDIRECT [[GI - Mouth through stomach]]

GI - Mouth through stomach

Admin — Wed, 16 Feb 2011 18:16:50 GMT

Admin: moved GI to GI - Mouth through stomach

*started here on 02/09/2011 at 1PM.

==GI==
*The duodenum is where the pancreatic duct terminates as well as the bile duct.
**Bile salts are for emulsifying fats and foods.
*Jejunum and ilium are histo indistinguishable.
*Duodenum has some secretions that make it distinct
*LI:
**Cecum, colon, rectum
**Can't be visually discerned.

===Oral cavity===
*Lined with non-kera stratified epith.
**Still have nucleus and organelles.
*The oral cavity between the epithelium are the lamina propria and submucosa.
*There are small salivary glands.

====Lip====
*There is a skin surface.
**Red region is '''vermillion''' where the caps come to the surface.
**Mucus membrane on the tooth side.
*Notice that the skin is much thinner than the mucus.
**The epithelium against wet surfaces is usually thicker (mucus membrane).
*The vermillion is the hairless part of the epithelium.
*There are also glands.
*The transition from the keratinized part (outside skin) to non keratinized (musu membrane)
**Vermillion

====Hard palate====
*Parakeratinized = for dealing with rough surfaces
*Hard palate and tongue deal with lots of tough material.
*In the mucus mebrane, there are nuclei at the surface but stain a little differently.
**We call this parakeratinized.
**They stain differently because they are toughed to deal with rough food.

====Tongue====
*Bumps are called papillae.
*Filiform papillae provide roughness.
**Cats have very sharp, extended filiform papillae.
*Filiform are rod like and have a parakeratinized surface.
*Fungiform papillae have bulbous ends.
**These are the red bumps on our tongues.
**Fungiform DO NOT have parakeratinized.
*Circumvallate papillae
**In the back.
**Have a valley.
**Valleys are flushed by serous glands called glands of Von Ebner.
*Filiform and fungiform in the '''f'''ront.
*Circumvallae in the back.
*Foliate papillae
**Most humans have very few
**Leaf shaped.
**Not very useful.
*Geographic tongue
**2% of people have this
**Comes with eating certain foods.
**A kind of psoriasis of the tongue.
**In the red area, the filiform papillae have retracted.
**Edges of the ridges have enhanced thickness of the epithelium.

====Taste buds====
*Found especially around the circumvalae and in the middle of the fungiforms.
*5 kinds of tastes: staly, sweet, sour, bitter, umami (glutamate, freshness).
*Taste cells with receptors on the tip; communicate with afferents.
*Basal cells are the stem cell.
*There is a pore in the epithelial cells for each taste bud (only by EM).

====Gingiva====
*Gingiva = gums of the mouth.
**Very well connected to the tooth.
**The epithelial attachment of gottlieb is where the gum epithelial cells attach to the mineral surface of the tooth.
*Sulcus is the space measured to see if there is some pathology.
**Deeper = unhealthy (perhaps gingevitis).
*Enamel covers the crown.
**Mostly appetite
**96% calcium salts
**Has some proteins but '''no collagen'''.
**Proteins are secreted by ameloblasts during tooth development deep in the gums.
**And there's no replacing it!
**Laid down in rod shapes, packed very tightly; makes it very hard.
*Cementum covers the root.
**Cementocytes secrete this.
**Cementum is very much like bone.
*Tooth sits in the alveolus (a bony cavity).
**This bone goes through fast turn-over, making it a ''woven'' type of bone.
**Alveolus just means something that is shaped like a cucumber.
*Dentin
**Makes up the bulk of the tooth (into the root, up into the crown).
**Harder than bone.
**Matrix of Type I collagen
**Odontoblasts make dentin
**Odontoblasts reside in the pulp cavity and project through the dentinal tubules (dentinal processes).
***These tubules are problably how we detect hot and cold with our teeth.

=====Pulp cavity=====
*Extends to the apical foramen (hole at the bottom of the tooth root).
*The pulp cavity is inside the root and crown.

=====Periodontal ligament=====
*Run between cementum and the alveolar bone.
*A set of bundles of collagen bound at one end on the tooth cementum (root of the tooth) and to the alveolar bone (supporting bone).
*The ligament distributes the force of the tooth throughout the whole alveolus.
**Like a bicycle tire and spokes.
*This is a type I collagenous structure.
**When the structure is rope-like it is generally Type I.
*It turns over pretty quickly.
*Scurvvy: teeth fall out because ligament doesn't get regnerated becuase new collagen can't be generated.

===Gut tube===
*Mucosa is the inner-most layer of the tubular gut
*Then connective tissue: sub-mucosa
**Most nerves and blood vessels
*Muscularis externa
**Main muscle layer
**Thickest
*Serosa
**CT with or without mesothelium

====Mucosa====
*Three layers: epithelium, lamina propria (CT), muscularis mucosae
*Lamina propria = nearby layer.
*Muscularis mucosae = muslce of the mucosa

====Submucosa====
*CT
*Some glands
**Important for identifying some organs
*Arteries and nerves

====Muscularis====
*Missed this.

====Serosa====
*Technically means "CT with mesothelium".
*Without mesothelia, it is just an adventitia.

===Esophagus===
*Statified squamous non-ker epithelium (like oral cavity)
*Lamina propria:
**Has no glands (for the most part)
**Muscularis mucosae: has longitudinal muscle, not continuous
**Know these three properties!
*The submucosa '''does''' have glands
**Provide lubrication for the esophagus.
*Muscularis externus
**Have inner circular and outer longitudinal muscle layers
**In the upper 1/3 the muscle is skeletal
***Makes sense because the first part of swallowing is voluntary.
**in the middle third, mixed
**Lower third is smooth muscle
*Serosa
**Mostly just CT (adventitia)
**Where it penetrates the diagragm (last part), has a mesothelia covering (so a true serosa).

===Stomach===
*Txn from esoph to stomach: squamous non-kera epith to simple columnar epithelium.
*Also, we start to see tubular glands.
*There are four parts: cardia (ring where esoph and stomach meet), fundus, body (fundus and body look same histologically), and pylorus (looks different).
*Lned with surface mucus cells.
*Surface invaginates into pits where glands empty.
*Diff between pit and gland:
**Pit is an invagination, covered with surface mucous cells.
**Glands empty contents into pits; not made of surface mucus cells.
*Rugae are longitudinal folds in the stomach for expansion.
**A fold in the mucosa of the stomach.
**The whole mucosa folds up, not the muscularis externae.
**In the center is the submucosa.

*The cardia has pits with some mucusy glands.

*The fundus / body have glands with a neck and base (base stains more basophilically).
**At the base, staining dark are chief cells that make pepsinogen so they have lots of protein production and packaging stuff that makes them dark.
**Parietal cells of the fundus / body make acids.
***Sometimes have two nuclei.
**The neck region has parietal and undiffed cells.
**Base has parietal and chief cells.
***Recall that chief are much darker staining (basophilic).

*The pylorus has deep pits and shorter mucusy glands.

*Pylorus into the small intestine:
**Pits and glands convert into villi.

==Lab 15: Digestive Tract I==

===A. ORAL CAVITY.===

====1. Lip, slide 47====
*Note that the epidermis of skin on the outer surface is thinner than the epithelium on the mucosal surface.
*Contrast the appearance of the dermis and the connective tissue underlying the mucosa.
*Compare the epithelium and the accessory structures on each surface. The epithelium on the mucosal surface is non-keratinized.
*Glands beneath this epithelium are compound seromucous glands.
*The organization of the mucosa in the oral cavity is not as well defined (structurally) as the wall of the tubular gut. The oral mucosa has no muscularis mucosae, so that the lamina propria is
continuous with the submucosa. This is difficult to see. We expect you to distinguish between
lamina propria and submucosa in the tubular gut, but not in the oral cavity.
*The red margin of the lip may be difficult to detect. Dermal papillae are much taller here
resulting in a thinner overlying epidermis. They also contain a prominent bed of capillaries.
How does this affect the color of this region in life?

====2. Oral mucosa====
*Slide 43.
* uvula; and slide 46, soft palate. Both
*The oral surface is lined by non-keratinized stratified squamous epithelium
**(What type lines the respiratory surface?).
*The oral surface also displays large mucous glands deep to the lamina propria.
**What tissue type lies deep to the glands?
*Note that this portion of the tract lacks a muscularis mucosae and a muscularis extema.
*As with the lip, a submucosa will not be readily distinguishable from the lamina propria on these slides.
*What is the function of the mucosal glands of the labial, buccal and palatine surfaces?

====3. Tongue====
*Study slide 41 for general features of the lingual mucous membrane and musculature.
*Filiform papillae are abundant on the dorsal surface.
*The epithelium is described as parakeratinized-the top several layers are pale (similar to the stratum corneum of skin) but all cell layers have nuclei (no anucleate squames).
*Some slides will show one or more fungiform papillae.
**Do these have taste buds? Yes
**If so, where are they located?
*What type of muscle is found in the tongue?
*How does organization of these muscle fibers relate to the function of the tongue?
*Slide 42 contains a circwnvallate papilla.
*Where are the taste buds located?
*The serous glands of von Ebner are associated with this papilla.
*Find the secretory cells of these glands and the duct that carries their product to the surface of the tongue.

===B. ESOPHAGUS===
*The upper region of the esophagus is on slide 48 (adjacent to trachea); the lower region is
on slide 52.
*The esophagus is the first of the tubular organs of the G.I. tract.
*Identify the various layers in the wall according to the generalized scheme for tubular digestive organs (see Lecture Notes, text and atlas).
*What specific type is it?
*What kind of muscle is present in the muscularis mucosae?
**(This will be harder to see on slide 52.)
*Are there any mucosal glands?
*Are there any submucosal glands?
*Where do the ducts empty?
*Examine the muscularis extema.
**How many layers?
**What is the direction of the muscle fibers in each layer?
*Compare the muscle types in the upper and lower portions of this organ.
**What type of muscle is present in each portion? Is the adventitia covered by a mesothelium?

===C. STOMACH===

====1. Body and Fundus====
. Use slide 53 to initially study the various layers in the wall. What
are rugae? What layers ofthe wall are involved? Note that various planes of section through the
rugae can complicate the morphological appearance of the mucosa.
Histology of the mucosa: Compare the epithelial cells lining the luminal surface, the
gastric pits, and the gastric (fundic) glands. What are their respective secretions? Is a brush
border present on any of the cells? (no) Note that the glands discharge their secretion into the
base of the gastric pits, which carry it to the mucosal surface. Be able to distinguish between
chief and parietal cells at the histologic and ultrastructural levels ( ftnd examples of TEM' s in
your text and atlas- such as Basic Histology 15-22, 15-24). Know their typical location within
the gland, and their function. Also know that mucous neck cells and enteroendocrine cells occur
in the glands (identification not required). Gastric glands are found in the fundus and body of the
stomach.

====2. Pyloric Stomach====
. Slide 54 contains the distal portion ofthe body and the proximal
portion of the pyloric stomach. Compare the histology of the two regions. Pay particular
attention to the pyloric glands. What kind of cells make up this epithelium? Where is the
muscularis mucosae in relation to the pyloric glands? Enteroendocrine cells are present, but not
stained.
Slide 40 is a section through the pylorus showi.llg both pyloric stomach and duodenum.
(Note: The surface epithelium of the duodenum is missing in most of this specimen, but other
structures are well preserved.) What type of muscle forms the pyloric sphincter?
69

*stopped here on 02/09/2011 at 2PM.

Main Page

Admin — Thu, 03 Feb 2011 21:35:03 GMT

Admin:

===Exam 1===
*[[exam_1_flashcards.txt]] (tdf)
*[[20110131_10_respiratory_notes]]
*[[20110126_07_lymphoid_organs_notes]]
*[[20110124_06_connective_cells_notes]]
*[[20110119_05_connective_tissue_notes]]
*[[20110112_04_circulatory_notes.txt]]
*[[20110110_03_epithelium_notes.txt]]
*[[20110105_02_nervous_notes.txt]]
*[[20110103_01_muscle_notes.txt]]

20110112 04 notes.txt

Admin — Thu, 03 Feb 2011 21:34:54 GMT

Admin: moved 20110112 04 notes.txt to 20110112 04 circulatory notes.txt

#REDIRECT [[20110112 04 circulatory notes.txt]]

20110112 04 circulatory notes.txt

Admin — Thu, 03 Feb 2011 21:34:54 GMT

Admin: moved 20110112 04 notes.txt to 20110112 04 circulatory notes.txt

*started here on 01/12/11

==Circulatory==
*First time we'll see tissues put together into tissues and organs.

===Objectives===
*At the conclusion ofthe unit on the circulatory system, each student should be able to:
**Sketch from memory the histologic structure of all ofthe vessels. Label the tunicae.
**Distinguish the relative functions of the parts ofthe vascular system, and correlate these with their structures.
**Describe the physical relationship ofpericytes to endothelial cells.
**List the four types of capillary and describe their similarities and differences. How do these differences relate to function?
**Describe the function of precapillary sphincters and arteriovenous anastomoses.
**List the metabolic functions ofendothelial cells, as described in the text.
**List the layers ofthe heart and distinguish between atrium and ventricle in the structures ofthese layers.
**Describe the specialized cells ofthe heart.
**Compare and contrast lymphatic vessels with blood vessels with regard to structure and function.

===Components===
*Heart
**Pumps to two systmes at once
**Has variable output and speed
***Yes, output, asin the volume
*Artieries
**Low capacity: hold little of the total blood
**Carry at high hydrostatic pressure
*Capillaries
**Low hydrostatic pressure
**High cross-sectional area
**Low flow velocity
**Good chance for diffusion with fluid around caps
*Veins
**Very Low hydrostatic pressure
**High and variable capacity
***Can hold 75% or can contract to hold less volume (if dehydrated) or expand (if well hydrated).

===Functions===
*Draw a heart, divide with two lines to make four sections.
**Atria and ventricles
*Blood goes out left ventrical to systemic capillaries (everything but the lungs)
*Blood comes back into venules and veins and right atrium.
*Then to right ventricle and to the pulomonary system (the lungs)
**We won't talk about pulmonary vessels this lecture.
**Theya re different because their pressure is different.
*Back into left atria and ventricle

===Histology of vessels===
*The vessels have layers, called tunics.
**Tunics were garmets, tight-fitting shirts.
*Layer closest to the blood is ''tunica intima''.
*Outside most layer is called ''tunica adventitia'' or ''tunica externa''.
**The layer that '''comes to''' the outside of the vessel.
*In between is the ''tuica intermedia''
**Contains muscle
*Vessels can have vessels in them: ''vasa vesorum'' (vessels of the vessels)
**This is to supply the outer cells of the bigger vessels.
*When we see smooth muscle in the vessels, there is probably innervation
**We usually won't see the nerves, though, because they are so small.

===Capillaries===
*Capillaries are about 10 microns, so blood cells just barely fit thorugh.
**In smaller capillaries, RBCs even have to change their shape and squeeze through.
*Not all capillaries are the same
**Different degree of permeability depending on where they are in the body.
**Thinner, more holes = more permeability
*Recall that a cell membrane is about 10 nm with proteins in it.
*Recall that we can see about 1 micron things as points via LM.
*Capilarries are usually 7-10 microns in diameter.
*They only have the tunica intima.
*Sometimes have pericytes with them
**Can replace other cells
**Can form new blood vessels
**Can undergo division
*Caps are simple squamous epithelium
*Continuous capilarries:
**Have a relatively thick (though very thin) extension of cytoplasm
**Found in muscle, nerve, connective tissue, and exocrine glands
***Like salivary glands seen on monday.
*Fenestrated capilarries
**Have windows = fenetre in french
**Found in kidney, GI, and endocrine glands (pit, thryroid)
**More leaky than continuous
*Fenestrated capilarries without diaphragm
**Have windows
**The windows do not have diaphragms that are like a piece of glass in the window
**Found in the renal glomerulus
**More leaky than fenestrated with
*Sinusoidal capilarries
**Bone marrow, liver, lymphod tissue
**Where lots of proteins move in and out of blood
**usually cells can move in and out pretty easily as well.

====Structures====
*Continuous
**Tight jxns with endothelial cells
**Have lots of penocytoic vesicles
***Looks like material is brought into cell from outside
**Not fenestri
**No diaphram
**BM is always present in continuous caps
**Tightest of caps
*Fenestrated with diaphragm
**A little leakier
**Have tight jxns with endothelial cells
**Have some pinocytotic vesicles
**Have fenestri, diaphragm, and bm.
*Fenestrated without diaphragm
**Tight jxns
**Pinocytoics
**Fenestri
**BM
*Sinusoidal
**Some tight jxns, but some of the endothelial cells don't form tight jxns with their neighbor.
**No pinocytoic vesicles
**Have fenestri, without diaphragm
**Discontinuous BM
**Leakiest.

====Image examples====
*Epithelial cells can wrap all the way around a vessel.
*Fenestrations:
**They are arranged in little collections.
*Pinocytotic vessles are much like the fenestra.
**Also called caveoli
**Can fuse to cause little diaphrams
*Diaphragm of fenestra
**Has spokes
**Made of PB1 and other proteins
**PB1 forms fibrilar spokes across the fenestra.

====Facts====
*Entrance to the capillary bed is controlled by the pre-capilarry sphincter.
**controls whether and how much blood flows into the capillary bed.
*Capillaries function to keep cells and protine in the blood.
**BBB exists to
**BBB is made up by continuous capillaries and the cellular barriers on the outside.
*Read 188-189 on function of endothelial cells
**A quesiton will coem from this for exam.

===Arteries and veins===
*The smalles arteries carrying blood away from heart are called arterioles.
**We'll define these as the smallest arteries with 1-5 layers.
*The venules are the smallest veins.
*Larger arteries are median arteries and median veins.
*Then we talk about larger arteries and large veins.
*This is all a continuous spectrum, though.
*We can see arterioles and their layers in lab.
**CT on the outside
**Venules accompany them
***Venules have much larger lumen compared to the thickness of the wall.
***That is, arteries have thicker walls relative to the luman than do venules.

Be able to fill out the table from scratch as it indicates you know your vessels.

*Tunica intima:
**In healthy tissue, all vessels contain only simple squamous epithelium called endothelium.
**large elastic artery:
**medium (muscular) artery:
**arteriole:
**capillary:
**venule:
**medium vein:
**large vein: the '''exception'''
***tunica intima of the large veins is a thicker layer as it includes connective tissue and smooth muscle.

*Tunica media:
**Manifests itself as smooth muscle in all vessles (except caps and venules where it does not exist)
**Some layers consist of additional materials
**large elastic artery: has elastic ''layers'' (lamini)
**medium (muscular) artery: has elastic ''fibers'' not ''layers''
**arteriole: not much eleastic fiber
**capillary: no tunica media at all
**venule: no tunica media at all
**medium vein:
**large vein:

*Tunica adventitia:
**On the outside
**Found on all larger vessels
**More on veins (that is, larger walls) than on arteries
**large elastic artery:
**medium (muscular) artery:
**arteriole:
**capillary:
**venule:
**medium vein:
**large vein: the '''exception'''
***has connective tissue
***has longitudinal bundles of smooth muscle

====Medium vessels====
*Comparison of medium (muscular) artery and medium vein.
**Muscular artery is on the left
**Medium vein is on the right.
*In general, the thickness of the artery wall looks greather than the vein wall.
**Tends ot be the case in most pairs of analogous artery and vein strcutreus.
*The relative thickness of the tunica adventitia of the vein is greater than the thickness of the tunic adventitia of the artery.
*The muscular artery
**Muscular layer is from tunica media
**Connective tissue = tunica adventitia
**Wiggly thing is internal elastic membrane common in medium arteries.
*More on tunica adventitia of muscular artery.
**Endothelial cells cover the surface (tunica intima)
**Internal elastic membrane is at the top part of the smooth muscle of the tunica media.
**Smooth muscle cells make the internal elastic membrane.
***So we consider it part of the tunica media (though some books disagree)
*Medium vein
**Endothelium on inside
**A bit of tunica media
**Tunica adventitia on outside
*There can also be external elastic membrane, too.

====Large vessels====
*Large elastic fibers have many elastic layers in the tunica media.
**Medium fibers only have internal elastic layer and maybe an external elastic layer.
*Large veins are the complicated one
**Longitudinal bundles of smooth muscle in tunica adventitia
**Longitudinal muslce in tunica intima, too.
*Large arteries have elastic lamini
*A healthy tunica intima of large vessels is hard to see because it is one cell thick.
*Large vein:
**Specimens don't stain well
**Find the muscle that runs around the vessel, this will be the tunica media.
**There is lots of connective tissue near the lumen, with the endothelium.
**Look for ''vasa vasorum'', too.

===Topics===
*Arteriole-venus anastamosis
**Used them when we played in the snow.
**Blood flow to skin shuts down.
**This is achieved by connecting artery and vein so the capillary bed is bypassed.
**This maintains normal blood flow in arteries and veins.

====Heart====
*has three tunics: endocardium, myocardium, epicardium
**differ in the atrium and ventricle.
*Endocardium:
**Atrium: Endothelium and connective tissue
**Ventricle: Only endothelium
*Myocardium:
**Atrium: Cardiac muscle
**Ventricle: Thick layer of cardiac muscle
*Epicardium:
**Atrium: Connective tissue and mesothelium
**Ventricle: Connective tissue and lots of larger vessels (coronary arteries), and mesothelium.
*Specialized cells:
**Nodal cells
***Set pace of heart
**Perkinje cells
***Modified cardiac muscle cells
***Carry signal from one part of the heart to another.

=====Observation=====
*Endocardium layer of atrium is thicker than the epicardium.
**Makes sense because the atrium may get stretched an endocardium will sustain the structure.
*Epicardium:
**Mesothelium on the outside is often simple squamous epithelium.
*Perkinje cells:
**Looke very diff
**Multiple nuclei and some myofibers
**But not packed full of contractile apparatus

===Lymphatics===
*Lymphatics drain ECF.
**Blood vessels leak
**Lymph vessels recover the fluid that has escaped the blood circulation
**Also impt for lymphatic cells
*Lymphatic capillaries:
**blind ended capillaries
**exist out in tissue
**Have incomplete fenestri
**have very few tight junctions
**have very little bm
**They are super leaky
*The cells of the lymph capillaries are anchored to the connective tissue around them by collagen fibrils.
**So when pressed, they are squished but open up upon freedom from pressure and as connective tissue spreads.
**This pulls fluid into it.
*Caps form larger vessels
**These have thinner walls than veins of similar size.

====Observations====
*Lymphatics sometimes have valves that keep lymph flowing in one direction.
*The walls may not be apparent; they can look like open space with endothelium lining it.

==Lab 6: Cardiovascular tissue==
*There are three layers to cardiac tissue:
**Tunica intima
**Tunica media
**Tunica adventitia
*In some parts of the cardiovascular tissues, one of these three tissues dominates over the others:
**The tunica media is dominant in all arteries (small to large).
**The tunica adventitia is dominant in most if not all veins.
*See Basic Histology 11-7.

===SMALL VESSELS===
*Arterioles and venules are the smallest of the arteries and veins, respectively.
*They are often seen as paired structures in connective tissue.
*Note that the arterioles will have a thick wall composed mostly of tunica media; venules will have a much thinner wall.
*Capillaries are very difficult to see in light microscopy because they are a single endothelial cell thick.
*Note that we use H&E as well as '''orcein''' to stain vessels.
**Orcein generates brown stains.

====Slide 10: Mesentery, human====
*This is an orcein and H&E stain.
*The arterioles and venules are easily seen to be paired.
*Arteriole observations:
**A thin tunica intima exists as a deep, purple, smooth band.
**A thick tunica media clearly distinguishes between arteriole and venule.
**The tunica adventitia is about half as thick as the tunica media and stains as a jagged band of cells.
*Venules
**The tunica intima stains a deep purple as in the arteriole but is not as smooth; each cell seems to jut out into the lumen.
**The tunica media is thinner than in the artiole with a more speckled pattern--less homogenous.
**The tunica abventitia of the venule gives a similar jagged stain but is slightly lighter.
***The two tunica adventitia are often adjacent.

====Slide 25: Lymph node, monkey====
*This is an orcein and H&E stain.
*Similar to slide 10.
*In this section, the venules tunica intima does not show the same jagged pattern as seen in the mesentery.
*Another difference is that in this section the arteriole's tunica adventitia has a definite wavy pattern as opposed to a jagged homogeneity.

====Slide 15: peripheral nerve====
*This is an H&E stain.
*Wavy pattern of arteriole tunica adventitia seen again.

===MUSCULAR (MEDIUM) ARTERIES AND MEDIUM VEINS===
*Medium arteries are also called muscular arteries because of the prominent smooth muscle found in the tunic media.
**However, in muscular arteries, the tunica adventitia is often thicker than the tunic media.
*Muscular arteries also have eleastic fibers running through them.
**These fold over themselves as contraction occurs.
*Some medium arteries show a prominent '''external elastic lamina''' in the tunica media.
*Elastic fibers can also be found running in the tunica adventitia.

====Slide 16: Aorta and mesenteric artery, human====
*This is an orcein and H&E stain.
*The elstic fibers of the tunica media are seen as blue-purple, folded, ghostly, fibers.
*A fairly continuous external elastic lamina can be seen in the transition between tunica media and tunica adventitia.
*Elastic fibers are visible in the tunica adventitia as pink connective tissue.

====Slide 25: Lymph node, monkey====
*This is an H&E stain.
*Elastic fibers of the tunica media are readily seen.

====Slide 10: Mesentery, human====

===ELASTIC (LARGE) ARTERIES===
*Note that this section is specific to arteries.
*We have seen elastic fibers as blue-purple in orcein + H&E; they will appear as read or brown with just orcein.
*In large vessels, ''vasa vasorum'' should be visible in the tunica adventitia

====Slide 16: Aorta====
*This is an orcein stain so elastic fibers will be red / brown.
*There is a definite border between the tunica media and the tunica adventitia.
*Though there is a distinction between the tunica media and the tunic intima, there isn't really a solid border.

====Slide 37: Aorta====
*This is an H&E stain so elastic fibers will be blue-purple.
*Again there is a definite border between tunica media and tunica adventitia but not between the tunica media and tunica intima.

*stopped here

===LARGE VEINS===
*Large veins like the vena cava have longitudinal bundles of muscle cells '''in the adventitia'''.
*Large veins also have thin tunica media.

====Slide 38: Vena cava====
*This is an H&E stain.
*Note that because the vena cava is a large vein, the media is thin and there are smooth muscle cells in the adventitia.
*The vasa vesorum are readily apparent, also.

===THE HEART===

====Atrium====
*The ventricle is easily identified as the tissue with epicardium (which has a high fat content) at the border.
*Note that coronary arteries are also visible, supplying oxygenated blood to the cardiac tissue.

====Ventricle====

=====Slide 19: Heart, ventricle and auricle=====
*Note that the epi, myo, and endo cardium of the atrium and the ventricle are visible.
**The epicardium of the atrium is especially thick.

=====Slide 20: Heart ventricle moneky=====
*In the ventricle, Perkinje fibers are visible but difficult to find.
**These fibers conduct the electricity of the heart.

*stopped here on 01/12/11.

20110110 03 notes.txt

Admin — Thu, 03 Feb 2011 21:34:35 GMT

Admin: moved 20110110 03 notes.txt to 20110110 03 epithelium notes.txt

#REDIRECT [[20110110 03 epithelium notes.txt]]

20110110 03 epithelium notes.txt

Admin — Thu, 03 Feb 2011 21:34:35 GMT

Admin: moved 20110110 03 notes.txt to 20110110 03 epithelium notes.txt

*started here on 01/10/2011 at 2PM.

==Intro to visual exam==
*They will be in MS326.
*Given via power point.
*Pointer on the slide will indicate what we are supposed to be identifying.
*There will be a multiple choice answer sheet.
*The questions can also be about the object, not just the identity of the object.
*There is about 1 minute per question.
**There are 50 questions per exam.
*There is a review session before the exam.
**Wednesday the 2nd of February.

==Epithelium lecture==

===Objectives===
*Understand the division oftissues into four classes, describing the characteristics of each.
*List the types ofjunctions found between epithelial cells and their unique characteristics. Which ofthese are also found in other tissue types?
*List the surface specializations of epithelial cells and their unique characteristics. Which of these are also found in other tissue types?
*Describe what is meant by epithelial polarity and how apical and basolateral membranes generally differ. Describe how separation oftransporters on an epithelial cell could enable secretion of a substance from the blood into the lumen of an organ.
*Distinguish among merocrine, apocrine, and holocrine modes of secretion. Which is used by serous cells? by mucous cells? by neuroendocrine cells? Can secretion of steroids be said to result from any ofthe three modes of secretion? Explain.
*Describe myoepithelial cells, their function and location.
*Describe the location, composition, and functions of basement membranes. Why is study of basement membranes so interesting with regard to cancer?
*Be able to draw and label all ofthe kinds of epithelia described in Table 4-2 ofyour text.
*Describe the development and classification of glands, as on pp. 76-80 of your text.

===Introduction===
*We classify everything in to four basic tissue groups.
**We've done muscle and nerve.
**Next week is the connective tissue.
*Epithelium is hard to describes but convers many of the functional tissues of the body.
*Epithelium has two general calsses:
**Cells that line a fluid filled space with tissue underneath.
**Chords or ropes of cells
***have lots of blood associated with their surface

===General characteristics===
*Closely spaced cells, not much space in between.
*Adhere closely to one another.
*Form sheets that line cavities or surfaces of organs (or the whole body, like skin).
*Sheet cells are involved in transport of material between compartments.
*These sheeted cells (and even those not in sheets) are polar.

===Epithelial junctions===
*There are terminal bars
**Composed of two EM structures (tight juxns and zonular adherens).
**shows up as a dark staining line at the connection between adjacent, connected, epithelial cells.
**These occur on the basolateral face of the cells.
*The terminal bar is dark between the tight jxns and zonular adheren proteins absorb the stain.

====Tight jxn====
*Tight jxns = zonula occludins
*Think of the old six-packs with plastic rings and where the ring held the cans (cells) together.
*Recall that these tight jxns are only visible on EM.
*Looks like a quilting in metal-shadowed freez-fracture EM.
*Tight jxns are very complicated.
*These effectively block the passage of fluid between adjacent cells.
*The tight jxns has two functions:
**as a fence: proteins on the basolateral side of the cell cannot pass onto the apical side and ''vice versa''.
**as a gate: can allow ions or molecules through,
***Depends on their selectivity, the signaling state of the epithelium, etc.
***Epithelium can be signaled to open their tight jxns to certain molecules.
*There are several protein components:
**ZO1 and ZO2 (zonulin occludin)
**Claudin
**Occludin
*These are important in structure and regulation.

===The belt desomosome===
*Called a desomosome because it looks a bit like a spot desomosome but is really different.
*At the top of the cell, below the zonula occludin.
*The zonula adheren is an important part of connecting the two cells and integrating the cytoskeletons, especially the terminal web.

===Maculla adherens===
*Not just epithelium but many cells have macula adherens.
*These are like spot welds between cells.
*Macula = spot
**Immacula = spotless
What's the difference between a macula densa and a desomosome?

*At the desomsoem, there is a plaque of prteoins in either cytoplasm, there are membraneous proteins and there are proteins that bridge between the two cells
**This is an important part of the strength of the skin surface.

===Hemi-desmosome===
*Half of a desomsome.
*These occur ont he base of the cells, to connect them to ECM (connective tissue).
*They have a plaque of cells in the cytoplasm, membraneous proteins.

*Intermediate filaments are important for hemi and full desomsoems.
**These are made of keratin.

*There is a large network of actin filaments called the terminal web.
**The actin filaments from the network can rup apically to generate the microvilli
**When we look at cancers, we sometimes look at their intermediate filaments; if they are made of keratins we usually call the tumor a carcinoma.

===Gap jxn===
*A connection between neighboring cells.
*Not a strong physical connection.
*Important functional connection.
*Membranes are head together with a fixed, narrow gap.
*Freeze fracture will help us see this.
*There are pores between one cell and it's neighbor allowing small molecules to pass through.
*Connexons make up these pores.
*One connexon from each cell alighn their channels to form a pore.
**There are many of these per gap jxn.
*The pore size is less than 1500 MW so signaling molecules like cAMP can get through but things like proteins cannot.
*Gap jxns are regulated in most cells by cytoplasmic Ca+ levels.
**If one cell gets injured, the ca+ rises and the neighbors shut their gap jxns so they don't get injured, too.
**It's the connexons that close.
*The connexon is the name of the structure, the protein is a connexin.

===Cells specializations===
*Microvilli are found on most cells of the lumen of the gut.
**They can generate a brush border if long enough and packed close enough.
**We also called them striated borders.
*The glycocalyx is sugar residues hainging off of glycoproteins and glycolipds of the cells.
**Can be stained by puriotic reactive sschiff reagent.
**made by actin
*Microplicae
**These are ridges that come up off the cell.
**Only seen via EM.
**Made by actin
*Steriocilia
**Made by actin
**Giatn microvili
**Called cilia because they can be seen individually with LM.
**There are steriocilia in the kidney and hair cells.
*Basal foldings
**"highly amnplified" basolateral surface means that there are lots of foldings to increase the surface area.
*Cilia and flagella
**Cilia are at the surface of epithelial structures.
**Flagella are generally singular.
**These have Microtubules to make up the axonea.
**This is a complex structure with many proteins.
**Genetic diseases in any of these proteins can cause defective cilia.
**We generally are thinking of '''motile cilia''' when we think of cilia.
**There are also '''primary cilia'''.
***These are important for epithelia cilia.
***These can be important for sensing the throw through the tubule, even, like in the kidney.

===Epithelial polarity===
*The apex is the part that faces the lumen or outside.
**AKA lumenal membrane
**AKA mucosal membrane
*Other side is the basolateral membrane
**AKA serosal membrane--closest to the serum or blood
**AKA Abluminal membrane.

===Secretion===
*Epithelial secretion:
**This is ambiguous.
**Often means from the blood side to the lumen; like absorption means from lumen to blood.
**More general is just release from the cell.
**In a glandular context: secretion means into lumen or blood, or ... not specific.
*Glandular secretion occurs in three ways:
**Merocrine: what we usually think of
***Material iin the cell, in a vesicle, which gets merged with the plasma membrane, material is released.
***Secretion of a product that is packaged int he cell.
***Hard to do this with things like fats.
**Apocrine:
***Move fat covered in proteoins to the inner membrane then wrap it in a very small amoutn of membrane and dump it into the ECF.
***This happens in arm pit and groin sweat glands; this gives us our special odor.
**Holocrine:
***When the entire epithelial cell is sloughed off to provide the secretion.
*Secretion can be constitutive or regulated.
**For example albumin is secreted constitutively.

====Protien secretion====
*There are two types of protein secretion:
**Serious cells:
***Cytoplasm stains well with H+E
***Ex: salivary gland
***Proteins being released in a watery fluid
***This is mericrine section.
**Neuroendocrine cells:
***Scattered throughout epithelia
***Have secretory granules on the blood side.
***This is mericrine section.

====Mucous secrtion====
*A special type of protein secretion.
*The proteins are covered withs ugars.
*Goblet cells are usually by themselves.
**CAlled this because the mucins get packaged together at the top (apical) of the cell and make it look like a goblet.
*Mucin is the protein.
**it has lots of sugars.
**sugars make it stay hydrated well
*In neuroendocrine cells we can concentrate the proteins in the vesicle into a small bundle.
**Mucin won't do this because it needs so much water.
*Also, mucin secreting cells won't stain well with H+E.
*Goblet cells have lots of ER
*They assume we know about the txn and txln and packaging of protines for secretion.

====Steroid secretion====
*STeoird are produced in special epithelial cells.
*Not packaged for secretion because it can pass through membranes.
*They can hardly hold the steroid in; perhaps by protein steric binding.
*These cells have ltos of:
**sER
**mt
***have shelf-like cristae instead of tube like cristae
**fat droplets (a precursor for many steroids)
Something here to study on our own.

===Basement membrane===
*The old literature calls basement membrane the basal lamina.
*This is an extra cellular structure.
*Has a lamina densa and one or two lamina rara (lamina lucida)
**Remnantas of dehydration.
**Used in pathoglogy to distinguish between disease states, especially in the kidney.
**Two if both cell layers adjacent to the bm are epithelial.
*Lamina reticularis:
**Set of fibrilar protins connected to the bm.
**not officially part of the bm.
*Basement membrane is at the basal surfave of most epithelial cells.
**Most neurve cells and msucle cells have their own bm.
*BM formed by type 4 collagen.
**This type does not form fibrils.
**Produces a felt-like structure in bm.
***Felt is a fabric that is made by gluing small fibers together, essentially. It is not woven like cotton.
*There are lots of glycoproteins in bm:
**laminin
***very large
*proteoglycans, too
**
*These molecules are really big.

====BM fxn====
*BM is an anchoring substrate for the epithelium.
**Some blistering disease states are from poor anchoring of skin epithelium to the bm.
*BM is a Signal template for differentiation
**Interfaces with regenerating cells to tell them what kind of cell to be and when and where to grow.
*BM is a filter for molecules
**Like in the kidney, removing proteins from filtrate.
*BM is a "filter" for cells
**it keeps cells where they are supposed to be.
**Most epithelial cells cannot get up and move (diapedesis), unless they have been altered, like in cancer.

===Epithelium types===
*We should be able to classify epithelium types and glands.
*Epithelium is named by shape of the cells at the surface:
**Squamous: flat like fried egg
***Often so flat that we cannot see cytoplasm in LM.
**Columnar: tall
**Cuboidal: like a cube
*Simple: one layer of cells
*Stratified epithelium have more than one layer of cells.
**Still named by cells at the surface.
**Most common is stratified squamous epithelium, which have fried eggs at the top but columnar at the bottom.
*Transitional epithelium
**Lines urinary passages, especially bladder.
**Armor plated cells at the surface (really acidic urine)
**Can withstand lots of stretch as a group
**Has "umbrella" cells at the surface that aren't quite cuboidal.
*Pseudostratified colunnar epithelium
**line ?
**have a jumble of nuclei
**All cells touch the bm, so it is falsly stratified.

==Laboratory 4: Epithelium==

===TYPES OF EPITHELIUM===
*Epithelial cells that form sheets are best viewed when the section is perpendicular to the plane of the epithelial sheet, so you will have to pay careful attention to the plane of section in each specimen.

====Simple sguamous epithelium====
*Cytoplasm is very thin and may not be visible.
*The nuclei may be flattened or rounded.

=====Slides 91 and 88: Bowman's capsule=====
*The bowman's capsule is a classic example of a squamous '''epithelium'''.
*The outer layer of the kidney is the cortex.
*Renal corpuscles are scattered throughout the kidney.
**The corpuscle looks like an empty space with a hemorrhage of cells filling it.
**The simple squamous epithelial cells surround the empty space.
*See Wheater, Fig. 16.6-16.17).
*The nuclei of the simple squamous epithelial cells are often close together.
**Though, often squamous cells are wide and therefore the nuclei are far apart.

*We can also find '''endothelium''' in slide 91.
**This is found lining the blood vessels of the kidney.
**Often the nucleus will be visible but all the cytoplasm will not.

*The last -elium is the mesothelium which is found on the outside of organs that face a space in the body, like the outside of the small intestine or the liver.
**We'll see the mesothelium when we look at cardiac tissue.
**Can be seen on slides 19, 54, and 10.
What is mesothelioma

====Simple cuboidal epithelium====

=====Slides 91 and 88=====
*Simple cuboidal epithelium make up most of the tubes in the kidney.
*These cells are nearly as tall as they are wide.
*The nucleus of simple cuboidal epithelium are slightly flattened or fully round.
*The cytoplasm is generally easily seen.
*These are informally called "high" or "low" if they are slightly tall or slightly wide.

=====Slide 87: Thyroid=====
*This slide of the thyroid has lots of cuboidal simple epithelium.
*The thyroid has follicles that are filled with colloid (a mixture with properties between those of a solution and fine suspension per wordnet).
*As colloid accumulates in the follicles, surrounding epithelial cells can be compressed.

====Simple columnar epithelium====
*Simple columnar epithelium are much taller than they are wide.
*The nuclei often elongate along the long axis in order to fit in the cell.

=====Slide 58: jejunum of monkey=====
*Note that the brush border can be seen as a sometimes-fuzzy-sometimes-defined layer on the apical surface of the columnar simple epithelial cells.
**It sometimes even looks like a cell membrane, with darker areas with a lighter middle--like longitudinal stripes.
**Compare with electron micrographs in Wheater (Fig. 14.25a&b) and
Basic Histology (Figs. 15-25, 15-28, 15-29).
*Note the goblet cells scattered individually in this epithelium.
Can you see a basement membrane? (probably not)

=====Slide 63: gallbladder=====
*Note that there is no goblet cells in the gallbladder as there are in the jejunum.
*Also, there is very little fuzziness or longitudinal striation because the microvilli are much smaller than in the jejunum.
**Note that mucus adhering to the apical surface of the gallbladder cells can look a bit like microvilli.

====Pseudostratified (ciliated) columnar epithelium====

=====Slide 48: Trachea=====
*This is the trachea.
*There are cilia present here in order to move mucus up the airway with trapped pathogen.
*Note that the mucins of the treacheal goblet cells stain more readily than those of the small intestine.
**Therefore, instead of appearing as a complete lack of stain, they give a granular, light pink-to-blue color.
*The basement membrane is clearly visible in the trachea as a thick pink band.
*Recall that pseudostratified columnar epithelium is not stratified because all the cells reach the basement membrane.
*Recall that basal cells are those epithelial cells that are the closest to the basement membrane.

====Stratified squamous epithelium====
*Stratifed squamous epithelium come in two flavors: keratinized and unkeratinized.
*In keratinized cells, the amount of keratinization will generally increase as the cells reach the lumem and this can change the appearance.
**They become lighter stained, wider, and have fewer and fewer nuclei.
*'''Note that to correctly identify stratified squamous epithelium, one must clarify wehther it is keratinized or non-keratinized'''.
**Keratinization seems to give the cell morphology a very irregular shape, to cause light staining, and to be associated with very few nuclei.
**The esophagus (non-keratinized) has a much more regular, flat shape, has many nuclei and still stains pretty well.

=====Slide 48: Esophagus=====
*The esophagus provides a good example of a non-keratinized stratified squamous cells.

=====Slide 30: Skin=====
*Here we see the layers of skin.
*Highly keratinized upper layers may be missing as it is hard to section them because they are so tough.

====Stratified cuboidal and columnar epithelium====
*We will see examples of cuboidal and columna stratified epithelium later.
*For now, examine these in Fig. 5.8 in Wheater.

====Transitional epithelium====

=====Slide 69: Urinary bladder=====
*The bladder is a good example of transitional epithelium whcih makes sense as it needs to be able to be very compact or very very distended.
**Transitional epithelium is known for its ability to stretch.
*The surface-lining cells are often called '''umbrella''' cells.
*The umbrella shapes give the greatest difference between distended and compact.
**In the distended state, the cells form a smooth layer with few bumps.
**In the compact state, the umbrella cells form baking-cookie shapes lying next to one another.
*Another difference in the distended and compact state is the concentratin of nuclei near the bm: lower density in the distended state.

====Epithelial transitions====
*Where two different types of epithelia meet, the tissue is often weak.
**This is often the site of lymphocyte accumulation.

=====Slide 81: Cervix=====
*The cervix has stratified squamous non-keratinizing (as we saw in the esophagus) and simple columnar cells.
**Note that there is also the endothelial cells of the blood vessels.
**Compare to Wheater 19.23.

===GLANDS===
*We will study glands more closely in each organ system.
*This lab will introduce us to glands.
*We should know the major classifications of glands as described in Basic Histology, Chapter 4, pages 77-79.
**These classes have, in part, to do with the ductal construction of the gland.
*It is hard to characterize the class of a gland by any single slide, so we will not be expected to classify glands based on their ductal architecture.
*All exocrine glands are considered complex.

*Gland objectives:
**At the completion of this portion of the lab you should be able to:
***distinguish between ducts and secretory units,
***distinguish between tubular and acinar secretory units, and
***distinguish between serous and mucous secretory cells

====Unicellular glands====
*Unicellular glands are individual cells scattered throughout a tissue.
*Unicellular glands have no duct at all.
*Examples include goblet cells, ween in slide 58 (small intestine) and slide 48 (epithelium of the trachea).
**Recall that the small intestine was a simple columnar epithelium and the trachea was a pseudostratified columnar epithelium.
Why does it make sense that the trachea is pseudostratified?
What's the special function of a pseudostratified epithelium?

====Multicellular glands====
*Multicellular glands have...multiple cells combining to form the gland.
*Only the very simplest multicellular glands lack ducts; most have some sort of epithelium-lined duct.
*There are two categories of multicelluarl glands:
**Simple: which have a single duct that is unbranched.
**Compound: which have a branched ductal system.
***All major exocrine glands have compound duct structures, but this can be hard to see in histological slides.

=====Exocrine glands=====
*The secretory unit of exocrine glands can be described as:
**elongated or tubular
**rounded or acinar.

====Slide 45: submandibular gland====
*In this slide we can see both serous and mucous cells.
**Serous cells are basophilic and therefore stain with eosin and are a deep pink.
**Mucous cells stain faintly
*Serous cells produce a watery, protein-rich secretion.
*Mucous cells produce glycoprotein-rich secretions.
*The submandibular gland is considerd compound, so it will have branched ducts.
*The gland is also considered tubuloacinar so it demonstrates both elongated ducts and rounded dcuts.
*The submandibular gland is also called '''mixed''' gland because it has both serous and mucosal secretion function.
*As the ducts proceed from small to large, they will shift from simple cuboidal to stratified cuboidal and then stratified columnar.
**Small ducts = simple cuboidal.
**Large ducts = stratified columnar.
I couldn't see this phenomenon.
*One can differentiate between the serous cells and the mucous cells by the way they stain with H&E:
**Serous cells stain blue / reddish-purple.
**Mucous cell are unstained.
**This makes sense because mucous cells will be generating vesicles full of glycoprotieins that won't stain well with H&E.
**On the other hand, mucous cell stain well with PAS.
***PAS = Periodic acid-Schiff stain
***Turns carbohydrates a deep magenta.
***It makes sense that mucous cells would be stained with this because they are secreting '''glyco'''proteins.

*Note that we will be expected to know which type of secretion is used by each gland we study.
*There are 3 types of secretion:
**merocrine: no loss of cytoplasm, vesicle fuses with membrane
**apocrine: some loss of cytoplasm
**holocrine: entire cell is shed
*One cannot determine the method of release through light microscopy.
*In the '''submandibular gland, both the mucosal and serous cells''' release their contents (glycoprotiens and watery protein, respectively) in a '''merocrine''' fashion.

====Endocrine glands====
*While exocrine glands release their contents via duct onto an epithelial surface (think pancreas into the duodenum), endocrine glands secrete their production into the blood.
*No ducts are necessary when secreting into the blood.

=====Slide 89: Adrenal gland=====
*Notice that the adrenal gland, which secretes hormones directly into the blood, has now duct system.
*Notice the numerous small blood vessels that pass through the structure.

===SPECIALIZED EPITHELIAL STRUCTURES===

====Basement Membrane====
*The basement membrane is composed of glycoprotiens.
*Therefore, like mucous secreting cells, it stains deep magenta with PAS (periodic acid-Schiff stain).
*Note that the basement membrane is usually not visible with H&E stain because of light staining and the very thin nature of the basement membrane.

====Cell surface specializations====
*One should be able to distinguish between cilia and microvilli.
**Slide 48, the trachea, shows cilia--long, individual fibers coming of in wavy patterns.
**Slides 58 and 63 (jejunum and gallbladder) demonstrate microvilli as a fine, soft, haze of stain around the cells.

*stopped here on 01/10/2011

20110105 02 notes.txt

Admin — Thu, 03 Feb 2011 21:33:42 GMT

Admin: moved 20110105 02 notes.txt to 20110105 02 nervous notes.txt

#REDIRECT [[20110105 02 nervous notes.txt]]

20110105 02 nervous notes.txt

Admin — Thu, 03 Feb 2011 21:33:42 GMT

Admin: moved 20110105 02 notes.txt to 20110105 02 nervous notes.txt

*started here on 01/05/2011 at 2PM.

===Lecture Objectives-Nervous System ===
#Describe the basic organization of the nervous system and the main structural features that distinguish the central nervous system from the peripheral nervous system.
#Define the unique cell types that make up nerve tissue and the structural specializations that distinguish neurons from glial and other supporting cell types.
#Understand the role of axonal transport in maintaining the structure and function of neuronal processes and synaptic terminals.
#Compare the structural and functional features of myelinated and unmyelinated axons and describe the basic events in axon myelination.
#Describe the structure and function of the synapse.
#Understand the structure of the spinal cord and the histological detail that distinguish the gray matter from the white matter.
#Compare and contrast the structure and organization of the somatic motor and visceral motor system.
#Define the structural features and functions of glial cell types.
#Understand structure/function correlates associated with nervous system pathologies including Alzheimer's disease, cerebral ischemia, multiple sclerosis and referred pain.

===NERVOUS SYSTEM ===
*Clinical relevance:
**11K injuries per year
**Stroke is third leading cuase of death and #1 cause of disability
**Parkinson's disease: 40K cases / year
***Neuronal degeneration
**Alzheimer's disease: 4.5 million cases, 100$ billion per year
***Brain volume decreases.

===Basic organization===
*Central nervous system (CNS)
**Brain:
***Gray matter and nuclei (surrounds the white area; there are also "nuclei" of grey mater in the center of the brain.
***white matter (nerve fiber tracts)
**Spinal cord:
*Peripheral nervous system:
**Ganglia: clusters of neuronal cell bodies.
**Nerve fibers:
***Efferent---motor, from CNS to peripheral
***Afferent: from peripheral to central, sensory
*Neurons and glial cells
**There are many more glial cells than neruons.

===Neurons===
*Neurons can be classified:
**Number of primary processes: multipolar (many processes), bipolar (two), pseudounipolar (rarely found in ...)
**Function: excitatory, inhibitory, modularatory
**By transmitter: gluatmic acid, GABAergic, dopamine, etc.
**Other: projection neurons, interneurons, pyramindianl neurons (shape), granule cells, etc.
*Examples
**multipolar, GABAergic, inhibitory, and has many spines (multi-spinous).
**?
**?
**Fake neuron, a large aspinous neuron, non-projection neuron (previous three are projection neurons)

===Cell body===
*AKA perikaryon, soma
*The nucleuous has a prominent nucleolus
Why?
*Have much rER, generates dots called Nissl bodies.
*Has golgi, MT (microtubules), and mts (mitochondria), IFs (called neurofilaments), lyposomes (lipofuscins).
*Mt look like cucumbers in shape.

===Dendrites===
*One of the two major types of processes: axons and dendrites.
*Dendrites receive inputs from all surrounding cells.
*There are primary dendrites that branch into small and smaller dendrites.
*There are samll dendrtitic spines
*There are apical and basalar dendrites.
*How do we determine apical versus basal?
**Apical will face away from the cortex of the brain (toward the exterior).
*There is a head and neck to the spines.
*What do the spines do?
**They seem to allow synapsing with neuron neighbors.

===Axon===
*Send info to ther neurons ("upward").
*Axons are much longer than dendrites.
*There is only one axon per nerve cell, though they can branch extensively.
*There is an axon hillock which is begun by the initial segment. Then there are collaterals given off and terminations in the "terminal".
*There are many MTs ant mts in the axon hilock.
*Axonal transprot moves material from the soma to the terminal and ''vice versa''.
**There are fast and slow transport of vesicles along the axon.
**Fast is several hundred mm / day
**Slow transport is a few mm / day, moves soluble components and cytoskeletal structures.
*There are two directions, too:
**Anterograde: from body to peripheral via '''kinesin'''
**Retrograde: from peripheral to body via '''dynein'''

===Synapse===
*The site of communication between two neurons.
*Two types of synapse:
**Electrical synapse
***Fxn through gap jxns
***Allows passage of ions form cell to cell.
***Few of these in mammals
***Very fast
**Chemical synapse
***Three components: presynaptic, synaptic cleft, postsynaptic.
***The postsynaptic component can be just about any part of the post-synaptic cell (dendrite, soma, axon, spine).
***Note that in chemical synapses, the signals must be converted from electrical in the presyn cell to chemical and back to electrical in the postsynap.
*How do synapses work?
**It's about the resting memebrane potential, the synaptic potential, and the action potential.
*Spines are not fixed; they are always changing in length, location, number of branches, etc.

===Glial cells===
*Oligodendrocytes in the CNS and Schwann cells in the PNS.
*Produce myeling sheath to cover axons.
*Myelin is a lipoportein complex, an insulation; keeps ions from flowing freely around the axon.
**With no myelin, bad transduction.
*In the CNS: a single oligodendrocyte generates the insulated area between nodes of ranvier.
*On an EM, the myelination shows as black area along the axon.
*Myelination and nodes of ranvier provide AP leaping which is faster.
*Unmyelinated firbers:
**In PNS, one schwann cell envelops many axons.
**No sheathes in CNS
**These have slow conductance.
Are all CNS / PNS myelinated / non myelinated?

===Spinal cord injury===
*Myelin is important for guiding regenerating axons.
*Bridging is an attempt to make regeneration work: put in a tube filled with schwann cells to help guide the regenerating axons passed the injury.
**It has been shown that axons may actually grow through the tube and help therapeutically.

===Astrocytes===
*Most numerous glial cells in CNS
*Two types
**Fibrous:
***Long, thin processes
**Protoplasmic astrocytes:
***Found in grey matter
***Short and fat processes
*Have end feet: connect to epithelium and sit on the external surface of the CNS
*Provide physical support for neurons
*Maintain homeostasis (toxin processing, extra NT processing, etc)
*Release neurotrophic factors (regulate transuction, still unknown)
*Can be found between two neurons and may help transduce signals
*Astrocytes can interact with neurons through the neuron's spine and their own form of a spine.
*Astrocytes are increased after ischemia of the brain (cns).
**So in early ischemia, astrocytes may proliferate in order to rescue the neurons.
**When ischemia is severe enough that neurons don't survive, the astrocytes generate a type of scarring material.

===Blood brain barrier===
*Important fxnal barrier to restrict exchange of substances between brain and blood.
*Has four components:
**Endothelial cells
***Provide an occluded junction which keeps even ions from passing between cells
***Have low transcytotic activity (that is, low transport into and out of the cytoplasm).
**There is a basement membrane
**There are end feet of astrocytes
**There are pericytes
***Provide another barrier in the BBB.
*All four of these form the BBB.

===Microglia===
*These are macrophages in the CNS
*Come from bone marrow
*In immune responses, they get turned on (IL4) and phagocytize stuff.
*They are generally very small compared to neurons and astrocytes.
*In MS, myelin is degenerated by microglia.
**In the inital phase: some pathogen enters the brain such that the microglia are activated.
**Then a second agent comes in and symptoms get worse.
**This gives the relapsing-remitting time-course of disease.
**There are abs generated against the myelin at increasing levels at each relapse.
*There are two forms of MS: RR and multi-organ MS.
**Many organs get attacked in MS.

===CNS===
*The brain is covered in neuro, we'll talk about spinal cord.
*There is a central canal which is lined with ependymal cells (celiated cuboidal epithelium).
*There is also grey matter
**Forms the dorsal, lateral, and ventral horns as well as the neuropil.
***Ventral = motor
***Dorsal = sensory
***Neuropil is anywhere without cell bodies.
*There is white matter:
**Descending and ascending fiber tracts

===PNS===
*Ganglia:
**Cell body collections
**Three types:
***Sensory,
***Autonomic ganglia
*Nerve fibers:
**myelinated and unmyelinated fibers
**Epineurium, perineurium, and endoneurium
***This is just like with muscle (endo / peri / epi myseum).
***A single neuron has myelin around it then the endoneurium.
***Several neurons will be bundled via perineurium.
***A whole nerve bundle will be surrounded by the epineurium.

===Somatic nerves===
*Two major types of nerves: somatic and visceral
*Two types of somatic nerves:
**Sensory
***Dorsal root ganglia
***Very precise as to where the signal came from.
**Motor
***from motor neurons to skeletal muscles
***Use ventral horn
***Fast
***Precise

===Visceral nerves===
*Control smooth muscle, glands, cardiac rhythm, and body homeostasis
*Two tyeps:
**Sensory
***From internal organs to CNS
***Go through DRG
***Difuse and vague
***Generate referred pain because conduction is back to the spinal cord, to the dorsal horn at the same place as the somatic sensory nerves. the brain may interpret the pain as somatic when it is actually visceral?
Can it be interpretted in the opposite way?
**Motor
***There is a sympathetic system
****The thoracolumbar division uses ach and sympathetic ganglia to control heart, glands, and smooth muscle
****Has short pregangliotic fibers and long post-gangliotic fibers.
****Functions to increase awareness and survival
***There is a parasympathetic system:
****the Craniosacral division uses ach and parasympathetic ganglia to control heart, gland, smooth muscle etc.
****The preganglionic fibers are relatively long; the postganglionic fibers are relatively short.
****Function to conserve energy.

==Lab==

===PERIPHERAL NERVE===

====Slide 9 sciatic nerve dog====
*Osmium tetroxide was used to fix these nerves.
**This preserves lipids and stains them brown or black.
**Adiposites in this slide show up as black.
**Myelin on this slide shows up as brown.
*The organization of the nerve fibers are seen:
**All three fibers are collagenous connective tissue.
**Epineurium is the outer layer:
***Coursest of the three layers
***Surrounds an entire '''nerve bundle'''
**Perineurium
***Surrounds the entire nerve bundle and projects deep into the bundle of axons to merge with the endoneurium.
***Easiest to identify it at the very outside edge of the axon.
***Seems a little more wavy and less collagenous than the epineurium.
**Endoneurium is the inner layer:
***Most delicate
***Immediately surrounds the myelinated axons.

*Myelin can be identified around each axon by it's brownish color that is circular in a cross-section and wide-spread in longitudinal cut.
**The myelin will surround the delicate endoneurium which is stained pink.
**Around the dark band of myelin, there is a small gap and then another, thinner dark band representing the outside edge of the schwann cells.
***This gap is larger than in real life as there is shrinkage of the myelin away from the schwann cell body.
*There is also shrinkage between the myelin and the cytoplasm of the axon which in this slide appears pink.

====Slide 15 Peripheral nerve====
*This slide is stained with Masson's trichrome
**Connective tissue will be a blue-green
**Nuclei will be a purple.
**Myelin is blotch white
*The schwann cell is wrapped around the axon so its nuclei stain is purple and arched around the axon like one expects the myelin to be.
*The nuclei of the distributed fibroblasts are slight better defined (sharper edges), are elongated, not arched, and are found in the midst of connective tissue (blue-green) as opposed to the blotchy whiteness of myelin.

*Unmyelinated axons can be seen on slide 15 and 9.
*These axons are tucked into invaginations of the cell membrane of schwann cells.
**These invaginations form channels for each axon.
**These will generally occur at very small axons.
**Recall that unmyelinated neurons will occur in the peripheral nervous system.
**These neurons will be to parasympathetic things like smooth muscle control because we don't need things to happen quickly.
*One cannot be sure that a neuron doesn't have myelin simply by light microscope so we are not responsible for determining if a neuron has myelin or not.

====Nodes of Ranvier====
*Nodes of Ranvier are generated by the end of one myelin covering and the beginning of another meet.
*The nodes can be identified in slide nine by the pinching of the pink endoneurium at a sharp point
**These nodes are very small in distance so with light microscope it is not possible to see the separation of the two myelin sheaths.
*Perpendicular to the pinched area will be a shriveled axon, much thinner than the distance between the layers of the endometrium on the sides of the axon.

====Slides 10, 82, and 25===
*"Other Examples of Peripheral Nerve: Several slides in the collection contain peripheral nerves. The nerves in slide 10 (mesentery) are easy to find. These are unmyelinated nerves. If you have time, take a look at slide 82 (spermatic cord) where most of the nerves are unmyelinated, and slide 25 (lymph node), which also contains unmyelinated fibers."
Need help finding neurons on slide 82.

===SPINAL CORD AND GANGLIA===
*Peripheral nerve fibers can contain somatic motor, visceral motor, and sensory neurons.
*The cell bodies of each neuron type is located in a specific area (either the spinal cord of the CNS or ganglia of the PNS):
*To understand why nervous tissues appear the way they do, it is helpful to understand where neuronal cell bodies reside.
*Be familiar with the following:
**Pseudounipolar (somatic or visceral) sensory neurons.
**Multipolar somatic motor neurons.
**Multipolar visceral preganglionic motor neurons.
**Multipolar visceral postganglionic motor neurons.

====Spinal Cord====

=====Slide 6 Spinal cord, cervical, monkey=====
*This slide uses a Nissl stain:
**Recall that rER in neurons is also called '''Nissl bodies'''
**Causes rER to be a deep blue
*In the ventral horn, multipolar visceral motor neurons can be identified by their heavy blue / purple staining of rER.
*

=====Slide 17 Spinal cord ganglion, mammal=====
*This is an H&E stain:
**Basophilic structures like the rER will be stained blue because of hematoxylin.
*One can identify the dorsal horn, the ventral horn, multipolar motor neurons in the ventral horn, and the dorsal root ganglion.
**Recall that the horns are grey matter, surrounded by white.
*The dorsal root sends afferent ("at" the CNS) fibers from the dorsal root ganglion to the dorsal horn of the spinal cord grey matter.
*The ventral root carries efferent ("exit" the CNS) fibers from the spinal cord to to visceral motor effectors.
*The ventral horn contains cell bodies of somatic motor neurons.
**These cells have much euchromatin and large nucleoli -- both signs of high metabolism.
*Multipolar cells will have several processes shooting off.
**There is however, only one axon.
**The axon may not be the largest process.
**The axon can be identified by the presence of the axon hillock.
**The axon hillock will stain lighter than rest of the cell because it has many MTs but little rER and few mt.

*"Neurons dispersed within tissue that has almost no intercellular space. Nuclei of the surrounding cells are easily visible, but cell boundaries are hard to see. There are many capillaries present, but most of the nuclei in the surrounding tissue belong to glial cells. The material surrounding the cell bodies is composed of processes of neurons and other glial cells, and is called the neuropil (a feature of the CNS)."

*The white matter has much smaller nuclei and a more homogenous speckled look (probably because the cells are running into and out of the cross-section instead of branching in parallel with the cross-section cut).
*Is there a name for the cells that bridge the grey and white matter?

*stopped here on 01/05/11 at 6PM.
*started here on 01/07/11 at 12:45PM.

*The lateral horn houses cell bodies of autonomic motor neurons that innervate smooth muscle and glands.
*Somatic motor neuron axons run through the ventral root and bypass the DRG.
*Visceral motor neurons have cell bodies in the ventral horn; axons travel through the ventral root, bypass the dorsal root ganglion, follow nerves that lead to peripheral ganglia.
But they don't synapse in the peripheral ganglia?
They just synapse directly on the motor cells?
**Note that this is a one-cell communication between the CNS (spinal cord) and the effector cell (skeletal muscle).
*The autonomic nervous system takes two cells for CNS-to-effector communication.
**Here there are preganglionic cells and post ganglionic cells with ganglia as their point of synapse.
**The cell body of the preganglionic cells is in the spinal cord.
**The cell body of the postganglionic cells is in the respective ganglia.
*There are two divisions to the autonomic nervous system: parasympathetic and sympathetic.
**The sympathetic system is characterized by short pre-ganglionic axons that synapse in ganglia that is very near to the spinal cord (think "sympathetic chain ganglion", etc.).
***Subsequently, the post-ganglionic fibers are much longer as they run to their effector cells.
**The parasympathetic system is characterized by long pre-ganglionic fibers that run to ganglia that are far from the spinal cord.
***Subsequently, the post-ganglionic fibers of parasympathetics are short fibers that run to effector cells that are close to their ganglia.

=====Structures=====
*Be able to find:
**White matter
**Grey matter
**Dorsal, ventra, and lateral horn
**Ventral root
**Dorsal root
**DRG
**Multipolar motor neurons (ventral horn)
**Axon hillock
**Nissl bodies
**Neuroglia
**Neurophil

====Dorsal Root Ganglion====

=====Slide 17=====
*In slide 17 one can see a dorsal root ganglion attached to the spinal cord.
*The dorsal root ganglion holds cell bodies of sensory neurons.
*These sensory neurons give off only one process, but it quickly splits into two.
**This is called '''pseudounipolar'''.
**One process heads to the spinal cord via the dorsal root, then horn.
***This process will synapse in the spinal cord with a neuron that will transduce the signal up the spinal cord.
**One process heads to the effector sensory cell.
*These sensory cells can be carrying either somatic or visceral sensory input.
*Sensory cells of the dorsal root ganglia are highly active and therefore have large nuclei, lots of euchromatin, and prominent nucleoli.
**Furthermore, they have lots of supporting cells surrounding them: '''satellite cells'''.
Look also for myelinated nerve fibers within the ganglion.

*Be able to identify:
**Dorsal Root Ganglion
***pseudounipolar somatic and visceral afferent ("at" the CNS) fibers.
**Ventral horn
***Multipolar somatic efferent ("exit" the CNS) fibers.
**Lateral horn
***Multipolar visceral efferent ("exit" the CNS) preganglionic fibers
***Multipolar visceral efferent ("exit" the CNS) postganglionic fibers
**Vertebral ganglion.
**Prevertebral ganglion.

====Autonomic Ganglion====

=====Slide 12=====
*This slide is of the sympathetic ganglia, which is part of the autonomic nervous system.
*Nissl stain and lipofuscin were used:
**Nissl causes rER to stain pink
**Lipofuscin gives cells a brown color
*Recall that ganglia are where post-synaptic cell bodies reside and synapse between pre-syn and post-syn neurons occurs.
**More specifically, because this is a sympathetic ganglia, short pre-synaptic fibers are synapsing upon bodies of long post-synaptic cells.
**And because this is a sympathetic ganglion, these neurons are visceral motor neurons.
***These will be efferent ("exit" the CNS) fibers.
*Sympathetic, visceral, post-synaptic motor neurons are:
**Multipolar
***But it is harder to see their processes than with the somatic motor neuron bodies of the ventral horn (which are also multipolar).
*Neurons in the sympathetic ganglion are surrounded by satellite cells.
**However, these satellite cells are not as numerous or tightly packed as those that we saw surrounding the neurons in the DRG (slide 17).
*One should also be able to identify myelinated and unmyelinated axons passing through the sympathetic ganglion.

====Miscellaneous====
*Osmium tetroxide preverves lipids (like those of myelin).
**Makes adiposites dark black because of all the lipids they hold.
**Makes myelin brownish around the axon of neuron.
*The three-neuriums are all connective tissue.
**Endoneurium is the most delicate.
**Epineurium is coarse connective tissue.
**Perineurium surrounds the nerve and projects deep into the bundle of axons where it blends with the endoneurium.

*stopped here on 01/07/11 at 2:15PM

20110103 01 notes.txt

Admin — Thu, 03 Feb 2011 21:33:26 GMT

Admin: moved 20110103 01 notes.txt to 20110103 01 muscle notes.txt

#REDIRECT [[20110103 01 muscle notes.txt]]

20110103 01 muscle notes.txt

Admin — Thu, 03 Feb 2011 21:33:26 GMT

Admin: moved 20110103 01 notes.txt to 20110103 01 muscle notes.txt

*started here on 01/03/2011 at 2PM

===What is this course===
*Structure-function correlation
*Structural foundation for physiology and pathology.
*Mescher writes the text book; he's at the Bloomington campus.

===Communication===
*Lecture slides posted on ANGEL
*Only 21 or 22 lectures.
*Three unit exams.
**Very thorough assessment.
**Exams are not cummulative.
*Last exam is NBME.
**Usually pretty reasonable.

===Lab===
*109-116
*Good place for studying
*Leo Thompson (MS 108)
**Fixes microscopes
*Alphabet starts in 114-116: A-O'Banner, then 109-110.
*Find your name in the lab, find your drawer, find your paper, key, and slides.
**Key on drawer goes on key ring; the other one stays in the drawer and opens the microscope cabinet.
*Ability to learn is a function of how well you use your microscope, so let them help you learn.

==Lecture==

===Classes of Tissue in Histo===
*Muscle (for contraction), nearve (for conduction), epithelium (for barriers, for glands), connective tissue (for holding things together and up).

===Slide ===
*

===Muscle===
*Skeletal muscle
*cardiac muscle
*Smooth muscle

===Skeletal muscle===
*Long
*A form of striated muscle (like cardiac)
*Have more than one nucleus
**Located at periphery
*Each muscle cell = a muscle fiber; interchangable.
*Myofibril (not a fiber) is an individual contractile intracellular organelle.
*Myofibrils are surrounded by the sarcoplasmic reticulum.
**Sarco from greek Sarcs = flesh.
*Cytoplasm = sarcoplasm.
*Sarcolemma = cell membrane

===Image===
*Striations are clear in longitudinal cut of striated muscle.
*Nucleus is at the periphery.
*Myofibrils can separate a bit within a cell.
*Human RBC = 7 micrometers across.
*Sections are 5-7 microns thick and are cut with a knife.
**This means there are some artifacts.

===Myofibrils===
*They are surrounded by sarcoplasmic reticulum.
*Skeletal muscle cells have a basement membrane on the outside of the sarcolemma, too.

===Muscle cuts===
*Fasicles are bundles of many muscle cells.
*Within a whole muscle lies individual cells which are held together by '''endomyseum'''.
*Bundles are defined by perimyseium.
*The epimyseum lies around an entire muscle.

===Myofiber in detail===
*Myofibrils are visible.
*The sarcomere is the contractile unit that is repeated to generate myofibrils.
*Thick and thin filaments make up the sarcomere and generate the striations.
*There is area where there is no thick filaments: called I bands because they don't change the orientation of polarized light.
*A bands are where thick filaments exist; they do change orientation of light.
*Z lines are where the thing filaments are anchored.
*The M line (may or may not be visible in EM) is where thick filaments are anchored.
*The H zone is where thick filaments don't overlap; surrounds M line.
*We should be able to identify all of these on an EM (electron micrograph).

===EM of Muscle===

===Myofilaments in detail===
*Thin filaments made of globular actin (which polymerizes to form filamentous actin).
*Thin filaments also have troponin complex and tropomyosin.
*Thick filaments are made of myosin.
*Thick filaments have a sort of long tail with two heads that come off like pineapple fruit.
*Myosin walks along the thin filament, pulling the thick filaments along the thin.

===Contraction in detail===
*Myosin has an ATPase site in each head which burns ATP down to ADP and Pi.
**The units are not released immediately after burn, though.
*If Ca+ is low, then tropomyosin will inhibit myosin to bind to thin filament.
**So ADP and Pi will be held on myosin but bind and contraction are not occurring.
*If Ca+ rises to 1 micromolar or greater, then Ca binds to TnC (troponin subunit of thin filament).
*TnI and TnT (parts of troponin) then are involved in conformational change.
**TnI binds actin.
**TnT binds tropomyosin.
*Calcium binding on troponin changes the conformation of troponin such that TnI comes up off actin which allows tropomyosin to move about 5 minutes around the clock face of the actin.
*This allows the head of myosin to bind in on the thing filament.
*Upon binding to actin, the Pi is released from myosin. This causes a conformational change--the '''power stroke'''.
*After the conformational change, the ADP is released.
*Release of ADP and Pi makes myosin high affinity for ATP such that it binds and gets burned causing a release of myosin from actin (hence ''rigor mortis'').

===Sarcoplasmic reticulum and calcium transport===
*Rise in Ca+ causes contraction.
*But these cells are huge, so how do we cause such an increase in an ion?
**In a normal cell we could just open the calcium channels and let it flow in, but it muscles it would take a long time for calcium to diffuse throughout.
**So we have a sarcoplasmic reticulum to deliver the Ca+ throughout the cell.
*The nerve signal comes from the outside the cell and depolarizes the membrane. But how does it talk to the sarcoplasmic reticulum?
**Via transverse tubules (T tubules)
**These stretch from cell membrane into the cell to touch the Sarcoplasmic reticulum via terminal cisternae.
**Two terminal cisternae with a A-I junction in between is called the triad.
*T tubules have a bit of basememnt membrane that dives into the cell along with the T cell.
*Note that mammals have T tuble going to A-I jxn whereas in others it goes to the Z line.

===Getting signal to muscle cell===
*Motor neuron brings the signal.
*Neuron and muscle jxn = synapse = nerve plate.
*One axon may innervate one myofiber or dozens.
*A motor unit is a single neuron and all the muscles it innervates.
**Motor units are either all or none; all cells contract when signaled.
**In the eye, we get fine motion and control becuase we have one nerve axon per myofiber.
**In the back, we have many myofibers per neuron because we don't need fine movement.

===Cardiac Muscle===
*Striated like skeletal muscle with some unique structures.
*Cardiac has branched cells; ;which are joined physically and electrically.
**Skeletal cells may be connected physically but not electrically.
**Skeletal don't pick up signal to fire from neighbors, but cardiac cells do, via electrical connection.
*Cardiac muslce have centrally located nuclei and only 1 or 2 nuclei.
*Something different about sarcolemma, too.
*Cardiac structures have intercalated disks which connect them to one another.
*Cardiac muscle is highly vascular but skeletal is much more limited.

===Intercalated disks===
*Allo cardiac cells to bind end to end.
*Have three junctions:
**Facial adherens
***Where thin filaments are joined together.
***A bit like zonula adherens.
***Where thin filaments joined to function as one between cells.
**Macula adherens
***Just a desmosome
***Where thick filaments pass between cells (?).
**Gap juctions
***Electrical connections.
***membranes come together very close at gap jucntions
***Don't physically hold cells together because they don't affect cytoskeleton.
***Occur along the longitudinal axis of the muscle cells, generally.
*Diads occur in cardiac cells...don't see one of the things of the triad; don't know what it was.
*ANP atrial naturetic peptid is released by what?

===Smooth muscle===
*All the cells are spindle shaped--a rod with tapered ends.
*Central nuclei.
*Much smaller than cardiac cells.
*In a cross section the cells are cut at different levels because of their tapering.
What is a "typical HNE cut"?
*Smooth muscles have thick and thin filaments but they are not organized into sarcomeres.
**They are also attached to intermediate filaments made of desmin and vimentin.
*Thin and intermediate filaments are linked by cytoplasmic '''dense bodies''' and membrane by '''membrane dense bodies'''.
**These cause dark bodies on the membrane and out in the cytoplasma.
**Dense bodies are where contractile skeleton connects to cytoskeleton.

===Contraction===
*Regulated in part by assembly and disassembly of intermediate filaments.
*Don't need T tubles to stimulate contraction because they are small.
*Stimulation causes phos of myosin which causes them to assemble inot thick filaments, allowing contraction.
*There is more regulation but we won't talk about it.
*Contraction is stopped by activation of phosphatase which cleaves off phosphorous of myosin and depolymerization.
*Smooth muscle contraction scrunches the cell into shorter and fatter, ball-like shape.
**This can cause the nucleus to corkscrew.

===Junctions in Smooth muscles===
*Can have gap jxns which means neighbors act in coordinate fasion: '''unitary smooth muscle'''
*Multi-unit smooth muscle is more tightly controlled by individual neruons.

===Regeneration of skeletal muscle===
*Because of satellite cells, we can regnerate some skeletal cells.
*Most smooth muscle can dedifferentiate and generate new cells.
*Cardiac cells cannot regenerate, only form fibrotic tissue.
*Process of skeletal regen:
**Satellite cells -> myoblasts -> myotubles (long, multiple cells bound together) -> myofibrillogenesis (fusion of cells) -> myofiber
**Satellite cells
***Reside just below basement membrane next to skeletal cells.
***May look like peripheral nucleus or fibroblast in our slides.
**Myoblasts
***Don't look like muscle cells but have similar expressiokn patterns.
***Can fuse to other myoblasts.
**Myotubes
***A syncitium of myoblasts.
**Myofibrillogenesis
***Formation of myofibrils of myotubes.
***Pushes nuclei outward
***Elongates cell.
**Myofiber

==Lab==

===Staining===
*H&E = hematoxylin and eosin
**Hematoxylin stains blue
***Hemotoxylin binds to acidic particles because it is basic.
***Stains upon reaction with Fe and Al.
***Stains chromatin, ribosomes,
**Eosin stains red / orange.
***Stains acidic particles.
***Stains connective tissue, cytoplasm, collagen, muscle fibers, and mt.

===Miscellaneous===
*Fats are dissolved away in fixation process leaving some areas vacant of tissue.
*Because these specimens were "immersion fixed" there may be RBCs floating around.
**RBCs are around 7 micrometers in diameter but around 10 micrometers when found in their normal environment--the vessel.
*Is the dark spot within the nucleus the nucleolus or the heterochromatin?
**It is the nucleolus.
**The difference between heterochromatin and euchromatin is a darkness thing; heterochromatin will be darker because it is condensed. The size of the nucleus will not necessarily change with the difference in hetero and euchromatin.
*Liver cells are typically 20-30 micrometers.
**So a 6-8 micrometer slice will not capture it all.
*Don't rely on color for identification.
*Nuclei of all types of muscle may corkscrew upon fixation.

===Smooth muscle===
*Uterus, appendix, bladder.
*The appendix (and the rest of the GI tract) has an inner circumferential and outer longitudinal layer of smooth muscle.
**The stomach is the opposite, though.
*The uterus has interlaced bundles of smooth muscle.
*The bladder has disparate bundles separated by connective tissue.
*Connective tissue is often stained an intense red (from eosin) and has few (fibroblast) nuclei present.

===Skeletal muscle===
*Soft palate, tongue,
*The soft palate showed glandular tissue, too, I think.
*There are transverse striations visible in skeletal muscle.
*Nuclei are many and on the periphery.
Is there connective tissue at the angular connections of differently oriented striations?
*Myofibrils appear as longitudinal striations in a longitudinal cut and as stippling in a cross-sectional cut.
*Myofibers are surrounded by endomysium; muscle cell bundles are surrounded by perimysium; gross muscles are surrounded by epimysium.

===Cardiac muscle===
*Striated
*Heart
*One or two nuclei per cell, centrally located.
*Cardiac muscle has intercalated disks and branched muscle cells.

*stopped here on 01/03/2011 at 5:35PM

20110110 03 epithelium notes.txt

Admin — Wed, 12 Jan 2011 12:39:12 GMT

Admin: Created page with '*started here on 01/10/2011 at 2PM. ==Intro to visual exam== *They will be in MS326. *Given via power point. *Pointer on the slide will indicate what we are supposed to be iden…'

*started here on 01/10/2011 at 2PM.

==Intro to visual exam==
*They will be in MS326.
*Given via power point.
*Pointer on the slide will indicate what we are supposed to be identifying.
*There will be a multiple choice answer sheet.
*The questions can also be about the object, not just the identity of the object.
*There is about 1 minute per question.
**There are 50 questions per exam.
*There is a review session before the exam.
**Wednesday the 2nd of February.

==Epithelium lecture==

===Objectives===
*Understand the division oftissues into four classes, describing the characteristics of each.
*List the types ofjunctions found between epithelial cells and their unique characteristics. Which ofthese are also found in other tissue types?
*List the surface specializations of epithelial cells and their unique characteristics. Which of these are also found in other tissue types?
*Describe what is meant by epithelial polarity and how apical and basolateral membranes generally differ. Describe how separation oftransporters on an epithelial cell could enable secretion of a substance from the blood into the lumen of an organ.
*Distinguish among merocrine, apocrine, and holocrine modes of secretion. Which is used by serous cells? by mucous cells? by neuroendocrine cells? Can secretion of steroids be said to result from any ofthe three modes of secretion? Explain.
*Describe myoepithelial cells, their function and location.
*Describe the location, composition, and functions of basement membranes. Why is study of basement membranes so interesting with regard to cancer?
*Be able to draw and label all ofthe kinds of epithelia described in Table 4-2 ofyour text.
*Describe the development and classification of glands, as on pp. 76-80 of your text.

===Introduction===
*We classify everything in to four basic tissue groups.
**We've done muscle and nerve.
**Next week is the connective tissue.
*Epithelium is hard to describes but convers many of the functional tissues of the body.
*Epithelium has two general calsses:
**Cells that line a fluid filled space with tissue underneath.
**Chords or ropes of cells
***have lots of blood associated with their surface

===General characteristics===
*Closely spaced cells, not much space in between.
*Adhere closely to one another.
*Form sheets that line cavities or surfaces of organs (or the whole body, like skin).
*Sheet cells are involved in transport of material between compartments.
*These sheeted cells (and even those not in sheets) are polar.

===Epithelial junctions===
*There are terminal bars
**Composed of two EM structures (tight juxns and zonular adherens).
**shows up as a dark staining line at the connection between adjacent, connected, epithelial cells.
**These occur on the basolateral face of the cells.
*The terminal bar is dark between the tight jxns and zonular adheren proteins absorb the stain.

====Tight jxn====
*Tight jxns = zonula occludins
*Think of the old six-packs with plastic rings and where the ring held the cans (cells) together.
*Recall that these tight jxns are only visible on EM.
*Looks like a quilting in metal-shadowed freez-fracture EM.
*Tight jxns are very complicated.
*These effectively block the passage of fluid between adjacent cells.
*The tight jxns has two functions:
**as a fence: proteins on the basolateral side of the cell cannot pass onto the apical side and ''vice versa''.
**as a gate: can allow ions or molecules through,
***Depends on their selectivity, the signaling state of the epithelium, etc.
***Epithelium can be signaled to open their tight jxns to certain molecules.
*There are several protein components:
**ZO1 and ZO2 (zonulin occludin)
**Claudin
**Occludin
*These are important in structure and regulation.

===The belt desomosome===
*Called a desomosome because it looks a bit like a spot desomosome but is really different.
*At the top of the cell, below the zonula occludin.
*The zonula adheren is an important part of connecting the two cells and integrating the cytoskeletons, especially the terminal web.

===Maculla adherens===
*Not just epithelium but many cells have macula adherens.
*These are like spot welds between cells.
*Macula = spot
**Immacula = spotless
What's the difference between a macula densa and a desomosome?

*At the desomsoem, there is a plaque of prteoins in either cytoplasm, there are membraneous proteins and there are proteins that bridge between the two cells
**This is an important part of the strength of the skin surface.

===Hemi-desmosome===
*Half of a desomsome.
*These occur ont he base of the cells, to connect them to ECM (connective tissue).
*They have a plaque of cells in the cytoplasm, membraneous proteins.

*Intermediate filaments are important for hemi and full desomsoems.
**These are made of keratin.

*There is a large network of actin filaments called the terminal web.
**The actin filaments from the network can rup apically to generate the microvilli
**When we look at cancers, we sometimes look at their intermediate filaments; if they are made of keratins we usually call the tumor a carcinoma.

===Gap jxn===
*A connection between neighboring cells.
*Not a strong physical connection.
*Important functional connection.
*Membranes are head together with a fixed, narrow gap.
*Freeze fracture will help us see this.
*There are pores between one cell and it's neighbor allowing small molecules to pass through.
*Connexons make up these pores.
*One connexon from each cell alighn their channels to form a pore.
**There are many of these per gap jxn.
*The pore size is less than 1500 MW so signaling molecules like cAMP can get through but things like proteins cannot.
*Gap jxns are regulated in most cells by cytoplasmic Ca+ levels.
**If one cell gets injured, the ca+ rises and the neighbors shut their gap jxns so they don't get injured, too.
**It's the connexons that close.
*The connexon is the name of the structure, the protein is a connexin.

===Cells specializations===
*Microvilli are found on most cells of the lumen of the gut.
**They can generate a brush border if long enough and packed close enough.
**We also called them striated borders.
*The glycocalyx is sugar residues hainging off of glycoproteins and glycolipds of the cells.
**Can be stained by puriotic reactive sschiff reagent.
**made by actin
*Microplicae
**These are ridges that come up off the cell.
**Only seen via EM.
**Made by actin
*Steriocilia
**Made by actin
**Giatn microvili
**Called cilia because they can be seen individually with LM.
**There are steriocilia in the kidney and hair cells.
*Basal foldings
**"highly amnplified" basolateral surface means that there are lots of foldings to increase the surface area.
*Cilia and flagella
**Cilia are at the surface of epithelial structures.
**Flagella are generally singular.
**These have Microtubules to make up the axonea.
**This is a complex structure with many proteins.
**Genetic diseases in any of these proteins can cause defective cilia.
**We generally are thinking of '''motile cilia''' when we think of cilia.
**There are also '''primary cilia'''.
***These are important for epithelia cilia.
***These can be important for sensing the throw through the tubule, even, like in the kidney.

===Epithelial polarity===
*The apex is the part that faces the lumen or outside.
**AKA lumenal membrane
**AKA mucosal membrane
*Other side is the basolateral membrane
**AKA serosal membrane--closest to the serum or blood
**AKA Abluminal membrane.

===Secretion===
*Epithelial secretion:
**This is ambiguous.
**Often means from the blood side to the lumen; like absorption means from lumen to blood.
**More general is just release from the cell.
**In a glandular context: secretion means into lumen or blood, or ... not specific.
*Glandular secretion occurs in three ways:
**Merocrine: what we usually think of
***Material iin the cell, in a vesicle, which gets merged with the plasma membrane, material is released.
***Secretion of a product that is packaged int he cell.
***Hard to do this with things like fats.
**Apocrine:
***Move fat covered in proteoins to the inner membrane then wrap it in a very small amoutn of membrane and dump it into the ECF.
***This happens in arm pit and groin sweat glands; this gives us our special odor.
**Holocrine:
***When the entire epithelial cell is sloughed off to provide the secretion.
*Secretion can be constitutive or regulated.
**For example albumin is secreted constitutively.

====Protien secretion====
*There are two types of protein secretion:
**Serious cells:
***Cytoplasm stains well with H+E
***Ex: salivary gland
***Proteins being released in a watery fluid
***This is mericrine section.
**Neuroendocrine cells:
***Scattered throughout epithelia
***Have secretory granules on the blood side.
***This is mericrine section.

====Mucous secrtion====
*A special type of protein secretion.
*The proteins are covered withs ugars.
*Goblet cells are usually by themselves.
**CAlled this because the mucins get packaged together at the top (apical) of the cell and make it look like a goblet.
*Mucin is the protein.
**it has lots of sugars.
**sugars make it stay hydrated well
*In neuroendocrine cells we can concentrate the proteins in the vesicle into a small bundle.
**Mucin won't do this because it needs so much water.
*Also, mucin secreting cells won't stain well with H+E.
*Goblet cells have lots of ER
*They assume we know about the txn and txln and packaging of protines for secretion.

====Steroid secretion====
*STeoird are produced in special epithelial cells.
*Not packaged for secretion because it can pass through membranes.
*They can hardly hold the steroid in; perhaps by protein steric binding.
*These cells have ltos of:
**sER
**mt
***have shelf-like cristae instead of tube like cristae
**fat droplets (a precursor for many steroids)
Something here to study on our own.

===Basement membrane===
*The old literature calls basement membrane the basal lamina.
*This is an extra cellular structure.
*Has a lamina densa and one or two lamina rara (lamina lucida)
**Remnantas of dehydration.
**Used in pathoglogy to distinguish between disease states, especially in the kidney.
**Two if both cell layers adjacent to the bm are epithelial.
*Lamina reticularis:
**Set of fibrilar protins connected to the bm.
**not officially part of the bm.
*Basement membrane is at the basal surfave of most epithelial cells.
**Most neurve cells and msucle cells have their own bm.
*BM formed by type 4 collagen.
**This type does not form fibrils.
**Produces a felt-like structure in bm.
***Felt is a fabric that is made by gluing small fibers together, essentially. It is not woven like cotton.
*There are lots of glycoproteins in bm:
**laminin
***very large
*proteoglycans, too
**
*These molecules are really big.

====BM fxn====
*BM is an anchoring substrate for the epithelium.
**Some blistering disease states are from poor anchoring of skin epithelium to the bm.
*BM is a Signal template for differentiation
**Interfaces with regenerating cells to tell them what kind of cell to be and when and where to grow.
*BM is a filter for molecules
**Like in the kidney, removing proteins from filtrate.
*BM is a "filter" for cells
**it keeps cells where they are supposed to be.
**Most epithelial cells cannot get up and move (diapedesis), unless they have been altered, like in cancer.

===Epithelium types===
*We should be able to classify epithelium types and glands.
*Epithelium is named by shape of the cells at the surface:
**Squamous: flat like fried egg
***Often so flat that we cannot see cytoplasm in LM.
**Columnar: tall
**Cuboidal: like a cube
*Simple: one layer of cells
*Stratified epithelium have more than one layer of cells.
**Still named by cells at the surface.
**Most common is stratified squamous epithelium, which have fried eggs at the top but columnar at the bottom.
*Transitional epithelium
**Lines urinary passages, especially bladder.
**Armor plated cells at the surface (really acidic urine)
**Can withstand lots of stretch as a group
**Has "umbrella" cells at the surface that aren't quite cuboidal.
*Pseudostratified colunnar epithelium
**line ?
**have a jumble of nuclei
**All cells touch the bm, so it is falsly stratified.

==Laboratory 4: Epithelium==

===TYPES OF EPITHELIUM===
*Epithelial cells that form sheets are best viewed when the section is perpendicular to the plane of the epithelial sheet, so you will have to pay careful attention to the plane of section in each specimen.

====Simple sguamous epithelium====
*Cytoplasm is very thin and may not be visible.
*The nuclei may be flattened or rounded.

=====Slides 91 and 88: Bowman's capsule=====
*The bowman's capsule is a classic example of a squamous '''epithelium'''.
*The outer layer of the kidney is the cortex.
*Renal corpuscles are scattered throughout the kidney.
**The corpuscle looks like an empty space with a hemorrhage of cells filling it.
**The simple squamous epithelial cells surround the empty space.
*See Wheater, Fig. 16.6-16.17).
*The nuclei of the simple squamous epithelial cells are often close together.
**Though, often squamous cells are wide and therefore the nuclei are far apart.

*We can also find '''endothelium''' in slide 91.
**This is found lining the blood vessels of the kidney.
**Often the nucleus will be visible but all the cytoplasm will not.

*The last -elium is the mesothelium which is found on the outside of organs that face a space in the body, like the outside of the small intestine or the liver.
**We'll see the mesothelium when we look at cardiac tissue.
**Can be seen on slides 19, 54, and 10.
What is mesothelioma

====Simple cuboidal epithelium====

=====Slides 91 and 88=====
*Simple cuboidal epithelium make up most of the tubes in the kidney.
*These cells are nearly as tall as they are wide.
*The nucleus of simple cuboidal epithelium are slightly flattened or fully round.
*The cytoplasm is generally easily seen.
*These are informally called "high" or "low" if they are slightly tall or slightly wide.

=====Slide 87: Thyroid=====
*This slide of the thyroid has lots of cuboidal simple epithelium.
*The thyroid has follicles that are filled with colloid (a mixture with properties between those of a solution and fine suspension per wordnet).
*As colloid accumulates in the follicles, surrounding epithelial cells can be compressed.

====Simple columnar epithelium====
*Simple columnar epithelium are much taller than they are wide.
*The nuclei often elongate along the long axis in order to fit in the cell.

=====Slide 58: jejunum of monkey=====
*Note that the brush border can be seen as a sometimes-fuzzy-sometimes-defined layer on the apical surface of the columnar simple epithelial cells.
**It sometimes even looks like a cell membrane, with darker areas with a lighter middle--like longitudinal stripes.
**Compare with electron micrographs in Wheater (Fig. 14.25a&b) and
Basic Histology (Figs. 15-25, 15-28, 15-29).
*Note the goblet cells scattered individually in this epithelium.
Can you see a basement membrane? (probably not)

=====Slide 63: gallbladder=====
*Note that there is no goblet cells in the gallbladder as there are in the jejunum.
*Also, there is very little fuzziness or longitudinal striation because the microvilli are much smaller than in the jejunum.
**Note that mucus adhering to the apical surface of the gallbladder cells can look a bit like microvilli.

====Pseudostratified (ciliated) columnar epithelium====

=====Slide 48: Trachea=====
*This is the trachea.
*There are cilia present here in order to move mucus up the airway with trapped pathogen.
*Note that the mucins of the treacheal goblet cells stain more readily than those of the small intestine.
**Therefore, instead of appearing as a complete lack of stain, they give a granular, light pink-to-blue color.
*The basement membrane is clearly visible in the trachea as a thick pink band.
*Recall that pseudostratified columnar epithelium is not stratified because all the cells reach the basement membrane.
*Recall that basal cells are those epithelial cells that are the closest to the basement membrane.

====Stratified squamous epithelium====
*Stratifed squamous epithelium come in two flavors: keratinized and unkeratinized.
*In keratinized cells, the amount of keratinization will generally increase as the cells reach the lumem and this can change the appearance.
**They become lighter stained, wider, and have fewer and fewer nuclei.
*'''Note that to correctly identify stratified squamous epithelium, one must clarify wehther it is keratinized or non-keratinized'''.
**Keratinization seems to give the cell morphology a very irregular shape, to cause light staining, and to be associated with very few nuclei.
**The esophagus (non-keratinized) has a much more regular, flat shape, has many nuclei and still stains pretty well.

=====Slide 48: Esophagus=====
*The esophagus provides a good example of a non-keratinized stratified squamous cells.

=====Slide 30: Skin=====
*Here we see the layers of skin.
*Highly keratinized upper layers may be missing as it is hard to section them because they are so tough.

====Stratified cuboidal and columnar epithelium====
*We will see examples of cuboidal and columna stratified epithelium later.
*For now, examine these in Fig. 5.8 in Wheater.

====Transitional epithelium====

=====Slide 69: Urinary bladder=====
*The bladder is a good example of transitional epithelium whcih makes sense as it needs to be able to be very compact or very very distended.
**Transitional epithelium is known for its ability to stretch.
*The surface-lining cells are often called '''umbrella''' cells.
*The umbrella shapes give the greatest difference between distended and compact.
**In the distended state, the cells form a smooth layer with few bumps.
**In the compact state, the umbrella cells form baking-cookie shapes lying next to one another.
*Another difference in the distended and compact state is the concentratin of nuclei near the bm: lower density in the distended state.

====Epithelial transitions====
*Where two different types of epithelia meet, the tissue is often weak.
**This is often the site of lymphocyte accumulation.

=====Slide 81: Cervix=====
*The cervix has stratified squamous non-keratinizing (as we saw in the esophagus) and simple columnar cells.
**Note that there is also the endothelial cells of the blood vessels.
**Compare to Wheater 19.23.

===GLANDS===
*We will study glands more closely in each organ system.
*This lab will introduce us to glands.
*We should know the major classifications of glands as described in Basic Histology, Chapter 4, pages 77-79.
**These classes have, in part, to do with the ductal construction of the gland.
*It is hard to characterize the class of a gland by any single slide, so we will not be expected to classify glands based on their ductal architecture.
*All exocrine glands are considered complex.

*Gland objectives:
**At the completion of this portion of the lab you should be able to:
***distinguish between ducts and secretory units,
***distinguish between tubular and acinar secretory units, and
***distinguish between serous and mucous secretory cells

====Unicellular glands====
*Unicellular glands are individual cells scattered throughout a tissue.
*Unicellular glands have no duct at all.
*Examples include goblet cells, ween in slide 58 (small intestine) and slide 48 (epithelium of the trachea).
**Recall that the small intestine was a simple columnar epithelium and the trachea was a pseudostratified columnar epithelium.
Why does it make sense that the trachea is pseudostratified?
What's the special function of a pseudostratified epithelium?

====Multicellular glands====
*Multicellular glands have...multiple cells combining to form the gland.
*Only the very simplest multicellular glands lack ducts; most have some sort of epithelium-lined duct.
*There are two categories of multicelluarl glands:
**Simple: which have a single duct that is unbranched.
**Compound: which have a branched ductal system.
***All major exocrine glands have compound duct structures, but this can be hard to see in histological slides.

=====Exocrine glands=====
*The secretory unit of exocrine glands can be described as:
**elongated or tubular
**rounded or acinar.

====Slide 45: submandibular gland====
*In this slide we can see both serous and mucous cells.
**Serous cells are basophilic and therefore stain with eosin and are a deep pink.
**Mucous cells stain faintly
*Serous cells produce a watery, protein-rich secretion.
*Mucous cells produce glycoprotein-rich secretions.
*The submandibular gland is considerd compound, so it will have branched ducts.
*The gland is also considered tubuloacinar so it demonstrates both elongated ducts and rounded dcuts.

*stopped here

Note the arrangement
of ducts within the gland. Going from small to large, the ducts tend to be composed of simple
cuboidal, stratified cuboidal, or stratified columnar epithelium (learning the specific names of
these ducts will come later!). This gland is also called a "mixed" gland (mixed-function gland)
because it consists of both serous and mucous secretory components. Note the difference in
staining with H&E of the cytoplasm of serous (blue/reddish-purple) and mucous (unstained)
22
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secretory cells. Relate this difference to ultrastructure of the cells and the composition of the
secretory products. On demonstration is a slide of the submandibular gland stained with
PAS for carbohydrate-containing components. Note that the mucus content of the
mucous-secreting cells is deeply stained compared to the contents of other cells. (See also PAS
staining of basement membranes, below).
Both of the secretory cell types in this gland release their products by a merocrine
mechanism. This means that the product is packaged in secretory vesicles, which subsequently
fuse with the plasma membrane to release their contents (with no loss of cytoplasm). Be sure to
read in your text to distinguish merocrine secretion from apocrine secretion (some loss of apical
cytoplasm) and holocrine secretion (entire cell is shed). You cannot tell the mode of secretion of
a gland by looking at histologic sections, but you will be expected to know what mode is used by
a particular gland. Most glandular cells employ merocrine secretion, but we will see examples of
glands that are known to use apocrine or holocrine secretion in later laboratory sessions.
b) Endocrine glands release their secretion directly into the blood. Take a quick
look at the adrenal gland, slide 89. This organ exhibits a feature characteristic of all endocrine
glands-- there are no ducts. Small blood vessels should be visible among the numerous
endocrine secretory cells.
C. SPECIALIZED EPITHELIAL STRUCTURES.
1. Basement Membrane. Visualization of basement membranes in most epithelia
can be enhanced by PAS staining. Study the slide of a submandibular gland stained with PAS
(on demonstration). The basement membrane beneath the epithelium of the ducts and the
secretory acini, not readily distinguishable with H&E staining, stains a deep magenta (mucous
cells also stain heavily, so that the basement membranes of the secretory tubules will not be
distinguishable). What chemical substance is responsible for the positive PAS reaction?
(glycoproteins)
2. Cell surface specializations. Make certain you can identify - and distinguish
between- cilia (e.g. slide 48 trachea) and microvilli (e.g. slides 58 jejunum and 63 gallbladder).
Review the structure of microvilli and cilia at the ultrastructural level.
23

*stopped here on 01/10/2011

Main Page

Admin — Wed, 12 Jan 2011 12:39:00 GMT

Admin:

===Exam 1===
*[[exam_1_flashcards.txt]] (tdf)
*[[20110110_03_notes.txt]]
*[[20110105_02_notes.txt]]
*[[20110103_01_notes.txt]]

20110103 notes.txt

Admin — Wed, 12 Jan 2011 12:38:23 GMT

Admin: moved 20110103 notes.txt to 20110103 01 notes.txt

#REDIRECT [[20110103 01 notes.txt]]

20110103 01 muscle notes.txt

Admin — Wed, 12 Jan 2011 12:38:23 GMT

Admin: moved 20110103 notes.txt to 20110103 01 notes.txt

*started here on 01/03/2011 at 2PM

===What is this course===
*Structure-function correlation
*Structural foundation for physiology and pathology.
*Mescher writes the text book; he's at the Bloomington campus.

===Communication===
*Lecture slides posted on ANGEL
*Only 21 or 22 lectures.
*Three unit exams.
**Very thorough assessment.
**Exams are not cummulative.
*Last exam is NBME.
**Usually pretty reasonable.

===Lab===
*109-116
*Good place for studying
*Leo Thompson (MS 108)
**Fixes microscopes
*Alphabet starts in 114-116: A-O'Banner, then 109-110.
*Find your name in the lab, find your drawer, find your paper, key, and slides.
**Key on drawer goes on key ring; the other one stays in the drawer and opens the microscope cabinet.
*Ability to learn is a function of how well you use your microscope, so let them help you learn.

==Lecture==

===Classes of Tissue in Histo===
*Muscle (for contraction), nearve (for conduction), epithelium (for barriers, for glands), connective tissue (for holding things together and up).

===Slide ===
*

===Muscle===
*Skeletal muscle
*cardiac muscle
*Smooth muscle

===Skeletal muscle===
*Long
*A form of striated muscle (like cardiac)
*Have more than one nucleus
**Located at periphery
*Each muscle cell = a muscle fiber; interchangable.
*Myofibril (not a fiber) is an individual contractile intracellular organelle.
*Myofibrils are surrounded by the sarcoplasmic reticulum.
**Sarco from greek Sarcs = flesh.
*Cytoplasm = sarcoplasm.
*Sarcolemma = ?

===Image===
*Striations are clear in longitudinal cut of striated muscle.
*Nucleus is at the periphery.
*Myofibrils can separate a bit within a cell.
*Human RBC = 7 micrometers across.
*Sections are 5-7 microns thick and are cut with a knife.
**This means there are some artifacts.

===Myofibrils===
*They are surrounded by sarcoplasmic reticulum.
*Skeletal muscle cells have a basement membrane on the outside of the sarcolemma, too.

===Muscle cuts===
*Fasicles are bundles of many muscle cells.
*Within a whole muscle lies individual cells which are held together by '''endomyseum'''.
*Bundles are defined by perimyseium.
*The epimyseum lies around an entire muscle.

===Myofiber in detail===
*Myofibrils are visible.
*The sarcomere is the contractile unit that is repeated to generate myofibrils.
*Thick and thin filaments make up the sarcomere and generate the striations.
*There is area where there is no thick filaments: called I bands because they don't change the orientation of polarized light.
*A bands are where thick filaments exist; they do change orientation of light.
*Z lines are where the thing filaments are anchored.
*The M line (may or may not be visible in EM) is where thick filaments are anchored.
*The H zone is where thick filaments don't overlap; surrounds M line.
*We should be able to identify all of these on an EM (electron micrograph).

===EM of Muscle===

===Myofilaments in detail===
*Thin filaments made of globular actin (which polymerizes to form filamentous actin).
*Thin filaments also have troponin complex and tropomyosin.
*Thick filaments are made of myosin.
*Thick filaments have a sort of long tail with two heads that come off like pineapple fruit.
*Myosin walks along the thin filament, pulling the thick filaments along the thin.

===Contraction in detail===
*Myosin has an ATPase site in each head which burns ATP down to ADP and Pi.
**The units are not released immediately after burn, though.
*If Ca+ is low, then tropomyosin will inhibit myosin to bind to thin filament.
**So ADP and Pi will be held on myosin but bind and contraction are not occurring.
*If Ca+ rises to 1 micromolar or greater, then myosing binds to TnC (troponin subunit of thin filament).
*TnI and TnT (parts of myosin) then are involved in conformational change.
**TnI binds actin.
**TnT binds tropomyosin.
*Calcium binding on troponin changes the conformation of troponin such that TnI comes up off actin which allows tropomyosin to move about 5 minutes around the clock face of the actin.
*This allows the head of myosin to bind in on the thing filament.
*Upon binding to actin, the Pi is released from myosin. This causes a conformational change--the '''power stroke'''.
*After the conformational change, the ADP is released.
*Release of ADP and Pi makes myosin high affinity for ATP such that it binds and gets burned causing a release of myosin from actin (hence ''rigor mortis'').

===Sarcoplasmic reticulum and calcium transport===
*Rise in Ca+ causes contraction.
*But these cells are huge, so how do we cause such an increase in an ion?
**In a normal cell we could just open the calcium channels and let it flow in, but it muscles it would take a long time for calcium to diffuse throughout.
**So we have a sarcoplasmic reticulum to deliver the Ca+ throughout the cell.
*The nerve signal comes from the outside the cell and depolarizes the membrane. But how does it talk to the sarcoplasmic reticulum?
**Via transverse tubules (T tubules)
**These stretch from cell membrane into the cell to touch the Sarcoplasmic reticulum via terminal cisternae.
**Two terminal cisternae with a A-I junction in between is called the triad.
*T tubules have a bit of basememnt membrane that dives into the cell along with the T cell.
*Note that mammals have T tuble going to A-I jxn whereas in others it goes to the Z line.

===Getting signal to muscle cell===
*Motor neuron brings the signal.
*Neuron and muscle jxn = synapse = nerve plate.
*One axon may innervate one myofiber or dozens.
*A motor unit is a single neuron and all the muscles it innervates.
**Motor units are either all or none; all cells contract when signaled.
**In the eye, we get fine motion and control becuase we have one nerve axon per myofiber.
**In the back, we have many myofibers per neuron because we don't need fine movement.

===Cardiac Muscle===
*Striated like skeletal muscle with some unique structures.
*Cardiac has branched cells; ;which are joined physically and electrically.
**Skeletal cells may be connected physically but not electrically.
**Skeletal don't pick up signal to fire from neighbors, but cardiac cells do, via electrical connection.
*Cardiac muslce have centrally located nuclei and only 1 or 2 nuclei.
*Something different about sarcolemma, too.
*Cardiac structures have intercalated disks which connect them to one another.
*Cardiac muscle is highly vascular but skeletal is much more limited.

===Intercalated disks===
*Allo cardiac cells to bind end to end.
*Have three junctions:
**Facial adherens
***Where thin filaments are joined together.
***A bit like zonula adherens.
***Where thin filaments joined to function as one between cells.
**Macula adherens
***Just a desmosome
***Where thick filaments pass between cells (?).
**Gap juctions
***Electrical connections.
***membranes come together very close at gap jucntions
***Don't physically hold cells together because they don't affect cytoskeleton.
***Occur along the longitudinal axis of the muscle cells, generally.
*Diads occur in cardiac cells...don't see one of the things of the triad; don't know what it was.
*ANP atrial naturetic peptid is released by what?

===Smooth muscle===
*All the cells are spindle shaped--a rod with tapered ends.
*Central nuclei.
*Much smaller than cardiac cells.
*In a cross section the cells are cut at different levels because of their tapering.
What is a "typical HNE cut"?
*Smooth muscles have thick and thin filaments but they are not organized into sarcomeres.
**They are also attached to intermediate filaments made of desmin and vimentin.
*Thin and intermediate filaments are linked by cytoplasmic '''dense bodies''' and membrane by '''membrane dense bodies'''.
**These cause dark bodies on the membrane and out in the cytoplasma.
**Dense bodies are where contractile skeleton connects to cytoskeleton.

===Contraction===
*Regulated in part by assembly and disassembly of intermediate filaments.
*Don't need T tubles to stimulate contraction because they are small.
*Stimulation causes phos of myosin which causes them to assemble inot thick filaments, allowing contraction.
*There is more regulation but we won't talk about it.
*Contraction is stopped by activation of phosphatase which cleaves off phosphorous of myosin and depolymerization.
*Smooth muscle contraction scrunches the cell into shorter and fatter, ball-like shape.
**This can cause the nucleus to corkscrew.

===Junctions in Smooth muscles===
*Can have gap jxns which means neighbors act in coordinate fasion: '''unitary smooth muscle'''
*Multi-unit smooth muscle is more tightly controlled by individual neruons.

===Regeneration of skeletal muscle===
*Because of satellite cells, we can regnerate some skeletal cells.
*Most smooth muscle can dedifferentiate and generate new cells.
*Cardiac cells cannot regenerate, only form fibrotic tissue.
*Process of skeletal regen:
**Satellite cells -> myoblasts -> myotubles (long, multiple cells bound together) -> myofibrillogenesis (fusion of cells) -> myofiber
**Satellite cells
***Reside just below basement membrane next to skeletal cells.
***May look like peripheral nucleus or fibroblast in our slides.
**Myoblasts
***Don't look like muscle cells but have similar expressiokn patterns.
***Can fuse to other myoblasts.
**Myotubes
***A syncitium of myoblasts.
**Myofibrillogenesis
***Formation of myofibrils of myotubes.
***Pushes nuclei outward
***Elongates cell.
**Myofiber

==Lab==

===Staining===
*H&E = hematoxylin and eosin
**Hematoxylin stains blue
***Hemotoxylin binds to acidic particles because it is basic.
***Stains upon reaction with Fe and Al.
***Stains chromatin, ribosomes,
**Eosin stains red / orange.
***Stains acidic particles.
***Stains connective tissue, cytoplasm, collagen, muscle fibers, and mt.

===Miscellaneous===
*Fats are dissolved away in fixation process leaving some areas vacant of tissue.
*Because these specimens were "immersion fixed" there may be RBCs floating around.
**RBCs are around 7 micrometers in diameter but around 10 micrometers when found in their normal environment--the vessel.
*Is the dark spot within the nucleus the nucleolus or the heterochromatin?
**It is the nucleolus.
**The difference between heterochromatin and euchromatin is a darkness thing; heterochromatin will be darker because it is condensed. The size of the nucleus will not necessarily change with the difference in hetero and euchromatin.
*Liver cells are typically 20-30 micrometers.
**So a 6-8 micrometer slice will not capture it all.
*Don't rely on color for identification.
*Nuclei of all types of muscle may corkscrew upon fixation.

===Smooth muscle===
*Uterus, appendix, bladder.
*The appendix (and the rest of the GI tract) has an inner circumferential and outer longitudinal layer of smooth muscle.
**The stomach is the opposite, though.
*The uterus has interlaced bundles of smooth muscle.
*The bladder has disparate bundles separated by connective tissue.
*Connective tissue is often stained an intense red (from eosin) and has few (fibroblast) nuclei present.

===Skeletal muscle===
*Soft palate, tongue,
*The soft palate showed glandular tissue, too, I think.
*There are transverse striations visible in skeletal muscle.
*Nuclei are many and on the periphery.
Is there connective tissue at the angular connections of differently oriented striations?
*Myofibrils appear as longitudinal striations in a longitudinal cut and as stippling in a cross-sectional cut.
*Myofibers are surrounded by endomysium; muscle cell bundles are surrounded by perimysium; gross muscles are surrounded by epimysium.

===Cardiac muscle===
*Striated
*Heart
*One or two nuclei per cell, centrally located.
*Cardiac muscle has intercalated disks and branched muscle cells.

*stopped here on 01/03/2011 at 5:35PM

20110105 notes.txt

Admin — Wed, 12 Jan 2011 12:38:09 GMT

Admin: moved 20110105 notes.txt to 20110105 02 notes.txt

#REDIRECT [[20110105 02 notes.txt]]

20110105 02 nervous notes.txt

Admin — Wed, 12 Jan 2011 12:38:09 GMT

Admin: moved 20110105 notes.txt to 20110105 02 notes.txt

Main Page

Admin — Sat, 08 Jan 2011 17:14:10 GMT

Admin:

===Exam 1===
*[[exam_1_flashcards.txt]] (tdf)
*[[20110105_notes.txt]]
*[[20110103_notes.txt]]

Flashcards.txt

Admin — Sat, 08 Jan 2011 17:13:52 GMT

Admin: moved Flashcards.txt to Exam 1 flashcards.txt

#REDIRECT [[Exam 1 flashcards.txt]]

Exam 1 flashcards.txt

Admin — Sat, 08 Jan 2011 17:13:52 GMT

Admin: moved Flashcards.txt to Exam 1 flashcards.txt

red stain eosin

blue stain hematoxylin

Exam 1 flashcards.txt

Admin — Sat, 08 Jan 2011 17:05:49 GMT

Admin:

red stain eosin

blue stain hematoxylin

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