gastrohistology

Question 1

liver

Answer 1

2.5% body weight

glissons capsule- simple squamous epithelium from peritoneum

Question 2

liver synthesizes

Answer 2

albumin, prothrombin, fibrinogen, a and b globulins, glucose, fatty acids, triglycerides, choslesterol, phospholipids, lipoproteins

Question 3

venous flow

Answer 3

portal v -> interlobar v -> interlobular v -> distribuiting v (perilobular v) -> inlet veule -> sinusoids -> central v -> sublobular -> collecting v -> hepatic v -> IVC

Question 4

arterial flow

Answer 4

interlobar a -> interlobular a -> distributing a -> inlet a -> sinusoids -> central a _> sublobular v -> collecting v -> hepatic v -> IVC

Question 5

lymph vessel

Answer 5

derived from the space of Disse

conveyed by periportal tissue space of Mall

Question 6

lobule

Answer 6

1x10^6
hepatocytes form a muralium 
radiate in polyhedron from central v
bloos enters at periphery 
percolates via sinusoids
leaves via central v
bile travels counter current leavinga at periphery

Question 7

hepatocytes

Answer 7

lifespan 150 days
large cells, most mononuclear
some binucleate
most cells polyploid
form a simple muralium: 2 cells thick in infants by 2 only 1 cell thick

Question 8

3 surfaces of hepatocytes

Answer 8

sinusoidal
basolateral
canalicular (within basolateral)

Question 9

sinusoids

Answer 9

10 um in diameter
space of disse 1-2 um where sinusoidal wall discontinuous w/ supporting reticular fibers
facilitates access of blood to hepatocytes
acellular gap

Question 10

other sinusoids

Answer 10

kupffer cells
endotheliual cells (non-fenestrated)
fibroblasts
lipocyts (Ito cell)
hematopoetic cells during early fetal life

Question 11

liver stoma

Answer 11

two overlapping CT trees: central vv, portal triad

sinusoids supported by reticular fibers, stroma altered by disease

Question 12

liver lobule types

Answer 12

classic lobule -> based on endocrine nature
portal lobule -> based on exocrine nature
portal acinus -> based on metabolic zonation

Question 13

classic lobule

Answer 13

polygonal in shape
portal canals at periphery and v in center
emphasizes endocrine function of gland (fibrinogen, albumin, glucose)
distinct CT capsule poorly developed in humans

Question 14

portal lobule

Answer 14

triangular in shape
portal canal in center
central v at periperhal apex
exocrine function (bile)

Question 15

portal acinus

Answer 15

rappaports lobule
portal tirads and CV lie at periphery, with long axis inbtwn
reflects gradient of metabolic activity
useful in describing hepatic regeneration, development of cirrhosis, centro-lobular necrosis

Question 16

zones of portal acinus

Answer 16

1- periportal zone, receives blood w/highest concentration of nutrients and oxygen, last to die, first to regenerate
2- mid-region, intermediate quality
3- centrolobular zone, lowest nutrients and oxygen content, first cells to die in centrolobular necrosis

Question 17

zonations

Answer 17

reflects differences in 
carbohydrate metabolism
protein metabolism
lipid metabolism
drug metabolism

Question 18

mitochondria

Answer 18

1000-2000/cell
half life 10.5 days
self replicating
oxidative phos, urea and TCA cycles, lipid ox

Question 19

lysosomes

Answer 19

catabolism- internal structures (autophagy) and exteral structures (heterophagy)
low internal pH for lysozyme activity
40-50 enzymes present

Question 20

tay-sachs disease

Answer 20

aka sphingolipidosis

absense of beta-hexoaminidase A which degrases acididc fatty gangliosides

Question 21

metachromatic leukidystrophy

Answer 21

aka sulfatidosis

absence of aryisulfatase causes accumulation of sulfates cerbrosides

Question 22

type II glycogenosis

Answer 22

acid maltase absent

Question 23

rER and golgi

Answer 23

plasma proteins (albumin, prothrombin, fibrinogen)
secreted in small clear vesicles (not granules)

Question 24

VLDL

Answer 24

transport apoproteins for lipoproteins is synthesized in rER
requires sER as well
converted to chylomicrons (not in hepatocytes) requires LPL

Question 25

sER

Answer 25

synthesis of cholesterol and phospholipids esterification of FFA to TGs dehaloginase converts T4-> T3 biotransformation of drugs, metabolites, and xenobiotics synthesis of cholic acid conjugation w/glycine and taurine to from bile acids Ca storage and release

Question 26

glycogen

Answer 26

polymeric storage of glucose -> glycogen rosettes gluconeogenesis storage to periportal area glucose to perivenous area rosettes associate w/SER

Question 27

peroxisomes

Answer 27

``` aka microbodies about 400/cell membrane bound purine catabolism produces uric acid oxidizes substrates peroxisome biogenesis; can bud from existing peroxisome or from rER ```

Question 28

microtubules

Answer 28

vesicular transport

Question 29

mircofiliments

Answer 29

submembranous and pericannilicular location | may be important in bile flow

Question 30

intermediate filiments

Answer 30

submembranous and pericannilicular location found in mallory bodies seen in variety of hepatic diseases

Question 31

endothelial cells

Answer 31

``` 48% of cells fenestrated and w/o diaphragm no pericytes basal lamina indistinct type IV collagen and laminin detectable ```

Question 32

fibroblasts

Answer 32

reticular fiber synthesis | type III collagen

Question 33

kupffer cells

Answer 33

fixed macrophage of the sinusoids (40% of cells) have Fc and C' receptors phagocytose bind and degrade hemoglobin to nbilirubin shared function w/splenic phagocytes highly toxic in high unbound concentrations transported to heptocyte for further processing can take over RBC degradation function of spleen

Question 34

Ito cells

Answer 34

aka hepatic lipocyte (fat cell) comprise 10% of non-haptocyte cells lipid droplets characteristic feature vitamin A rapidly taken up and stored in lipid droplet take up lipophylic/membranolytic milecules which damage lysosomes

Question 35

biliary space

Answer 35

intrahepatic channels | extrahepatic ducts

Question 36

intrahepatic channels

Answer 36

bile canniculus terminal ductules interlobar bile ducts

Question 37

extrahepatic ducts

Answer 37

``` right and left hepatic ducts proper hepatic duct cystic duct common bile duct collumnar w/occasional mucous cells general plan similar to gut ```

Question 38

bile canaliculus

Answer 38

.5-1.5um diameter channels sealed by zonula occludens and desmosomes golgi and sER oriented toward bile canaliculus

Question 39

terminal ductules

Answer 39

transition from cnaliculus to interlobular bile ducts basal surface attached to hepatocytes flattened to cuboidal epithelium bicarbonate-secreting pinocytotic vesicles modify bile

Question 40

interlobular bile ducts

Answer 40

cuboidal to columnar epithelium surrounded by elastic and collagen CT may modify bile by additional bicarb secretion surrounded by smooth m @ porta hepatis -> narrowing of ducts can be see in cholangiograms

Question 41

cystic duct

Answer 41

spiral folds in mucosa due to twist of gallbladder neck

Question 42

common bile duct

Answer 42

circumfrential smoth m sphincter present | sphincter of Boyden located prior to jnx w/pancreatic duct

Question 43

gallbladder

Answer 43

30-50cc | filled surface is even, empty folds or rugae

Question 44

gallbladder mucosa

Answer 44

simple columnar epi w/microvilli lateral junctional complexes (desmosomes) capable of extracting water, inorganic salts, other electrolytes Rokintansky-Aschoff crypts- invaginations of surface epi mucous glands- appear at neck of gallbladder

Question 45

gallbladder lamina propria

Answer 45

thin layer of dense irregular CT numerous small blood and lymph vessels NO muscularis mucosa

Question 46

submucosa

Answer 46

None in gallbladder

Question 47

gallbladder serosa

Answer 47

thick layer of dense irregular CT abundant aa, vv, and lymph mesothelium covers underlying CT