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Flashcards in gastrohistology Deck (47):
1

liver

2.5% body weight
glissons capsule- simple squamous epithelium from peritoneum

2

liver synthesizes

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

3

venous flow

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

4

arterial flow

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

5

lymph vessel

derived from the space of Disse
conveyed by periportal tissue space of Mall

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lobule

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

7

hepatocytes

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

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3 surfaces of hepatocytes

sinusoidal
basolateral
canalicular (within basolateral)

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sinusoids

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

10

other sinusoids

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

11

liver stoma

two overlapping CT trees: central vv, portal triad
sinusoids supported by reticular fibers, stroma altered by disease

12

liver lobule types

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

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classic lobule

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

14

portal lobule

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

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portal acinus

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

16

zones of portal acinus

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

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zonations

reflects differences in
carbohydrate metabolism
protein metabolism
lipid metabolism
drug metabolism

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mitochondria

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

19

lysosomes

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

20

tay-sachs disease

aka sphingolipidosis
absense of beta-hexoaminidase A which degrases acididc fatty gangliosides

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metachromatic leukidystrophy

aka sulfatidosis
absence of aryisulfatase causes accumulation of sulfates cerbrosides

22

type II glycogenosis

acid maltase absent

23

rER and golgi

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

24

VLDL

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

25

sER

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

26

glycogen

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

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peroxisomes

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

28

microtubules

vesicular transport

29

mircofiliments

submembranous and pericannilicular location
may be important in bile flow

30

intermediate filiments

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

31

endothelial cells

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

32

fibroblasts

reticular fiber synthesis
type III collagen

33

kupffer cells

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

34

Ito cells

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

35

biliary space

intrahepatic channels
extrahepatic ducts

36

intrahepatic channels

bile canniculus
terminal ductules
interlobar bile ducts

37

extrahepatic ducts

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

38

bile canaliculus

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

39

terminal ductules

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

40

interlobular bile ducts

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

41

cystic duct

spiral folds in mucosa due to twist of gallbladder neck

42

common bile duct

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

43

gallbladder

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

44

gallbladder mucosa

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

45

gallbladder lamina propria

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

46

submucosa

None in gallbladder

47

gallbladder serosa

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