Liver Histology and Physiology

Question 1

Portal triad

Answer 1

portal vein
hepatic a.
bile ductule
lymph vessel

Question 2

mauralium

Answer 2

walls of hepatocytes that radiate from the central vein
1 cell layer thick in adults
2 cells thick in infants
contains many bi nucleate cells, many cells are polyploid (4N)
sinusoidal surface
basolateral surface (with bile canalicular)

Question 3

space of disse

Answer 3

gap b/w hepatocyte and endothelium of epithelium

blood cells cannot enter

Question 4

classic lobule

Answer 4

polygonal in shape
portal triads at periphery
central vein at the center
**emphasis on blood flow, therefore ENDOCRINE:fibrinogen, albumin, glucose

Question 5

Portal lobule

Answer 5

triangular shaped
portal canal in center
central vein in peripheral
EXOCRINE: synthesizes and secretes products into the bile duct

Question 6

Portal acinus

Answer 6

poratal triads and central veins lie at periphery
long central axis b.w two classic lobules with central vein at apex of the lobules
reflects gradient (zonation) of metabolic activity
METABOLISM: hepatic regeneration, devo of cirrhosis, centro-lobular necrosis

Question 7

zonation

Answer 7

peripheral to central

gradient of metabolic activity w/in the liver

Question 8

zone 1

Answer 8

nearest to the portal triad
healthiest hepatocytes due to high blood flow
last to die, first to regenerate

where the most metabolism occurs

Question 9

zone 2

Answer 9

mid region

intermediate quality

Question 10

zone 3

Answer 10

centro lobar zone
least healthy
lowest O2 and lowest nutrients
first cells to die in centrolobar necrosis

Question 11

sphincter of boyden

Answer 11

located on the CBD before the merge

Question 12

Rokintansky Aschoff crypts

Answer 12

located in the GB

invaginations of surface epithelium

Question 13

stellate or ito cells

Answer 13

fat or vitamin A storing, found mostly in the Space or disse and within the sinusoidal space

however when irritated by any major disruption in hepatocyte functioning , turn into myofibroblasts—>secrete collagen—>fibrosis—>necrosis—>cirrhosis

Question 14

hepatic cirrhosis

Answer 14

abnormal regeneration occurs in which CT elements don’t cooperate in regeneration

stroma is altered in disease states.
reticular fibers thicken and alters normal function by blocking off the lobule

Question 15

partial hepatectomy

Answer 15

hepatocytes of all zones regenerate

liver recovers to nearly the same mass as pre-surgery

Question 16

zonal damage

Answer 16

seen in pathology
selective regeneration of damaged zones
as opposed to regeneration in all zones

Question 17

lysosomes

Answer 17

create a low pH environment that catabolizes internal and external structures with help of enzymes from the rER
*degrade receptor-ligand complexes
lack of enzymes—>disease (Tay Sachs etc)

Question 18

glycogen rosettes

Answer 18

polymeric storage form of glucose

located near sER and associated with glycogenolysis enzymes on sER

Question 19

Peroxisomes

Answer 19

membrane bound
H2O2 and O2 metabolizes purines, AAs, ETOH, Nitrite, lactate)
bud from previous peroxisomes or the rER

Question 20

Kupffer cells

Answer 20

fixed macrophage of sinusoids (40% of all cells)
have Fc and C’ receptors
phagocytose immune complexes, bacteria, non-immune particles

***degrade Hb—>Br (shared fx with spleen)

Question 21

bile canaliculus

Answer 21

receives bile from the golgi/sER

sealed by zonal occludens and desmosomes

Question 22

terminal ductules

Answer 22

transition from canaliculus to interlobular bile ducts
basal surface attached to hepatocytes
flattened to cuboidal epi
*secrete bicarb and water which modify the bile produced in the hepatocytes
**stimulated by secretin

Question 23

interlobular bile ducts

Answer 23

cuboidal-->columnar epithelium 
surrounded by elastic and collagen CT
more bicarb
surrounded by smooth muscle at porta hepatis--->narrowed ducts 
last stop before extraheptic bile ducts

Question 24

gall bladder histology

Answer 24

mucosa= simple columnar epi with microvilli that is capable of extracting water, salts and electrolytes. held together by lateral junctional complexes (desmosomes)
Rokitansky Aschoff crypts
mucus glands may appear in the neck
**NO submucosa

Question 25

Sphincter of oddi

Answer 25

located in the ampulla of vater | regulates flow out of the CBD and pancreatic duct

Question 26

3 steps to bile formation

Answer 26

1) Hepatocytes actively secrete bile into the canaliculi 2) intra and extrahepatic bile duct epithelium secrete bicarb and water (creates dilute "hepatic" bile) 3) Half the hepatic bile is diverted into the the GB where the bile is iso-osmotically removes salts and water --->concentrated GB bile **the bile that eventually reaches the duodenum is a mix of concentrated GB bile and dilute hepatic bile

Question 27

4 components of bile

Answer 27

1) Bile salts (from chol metabolism): act as detergents for fat metabolism 2) Cholesterol and phospholipids 3) Bilirubin: comprises only .3% of bile, from RBC metabolism, causes jaundice 4) proteins, misc, Bicarb * bile is reabsorbed in the SI

Question 28

Canalicular flow

Answer 28

from hepatocytes--->canaliculi Independent+ dependent Total bile flow= canalicular + ductular

Question 29

Ductular flow

Answer 29

Constant (independent)

Question 30

Independent flow

Answer 30

depends on presence of organics and osmotic force | i.e. increase glutathione=increased osmotic driving force= increased bile formation

Question 31

dependent flow

Answer 31

depends of negatively charged bile salts in micellar form and out of solution which has a low osmotic force

Question 32

Things that increase bile secretion

Answer 32

Secretin, glucagon, VIP

Question 33

things that inhibit bile flow

Answer 33

somatostatin | via enhancing fluid reabs by bile ducts

Question 34

enterhepatic circulation

Answer 34

the majority of bile salts are reabsorbed via active transport in the distal ilium and transported back to the liver via hepatic portal vein

Question 35

Cholestasis

Answer 35

suppression of bile secretion: 1) regurg of bile components into the circulation (jaundice) 2) damage to hepatocytes (elevated ALP) 3) impaired lipid digestion and abs caused by either obstruction of extrahepatic ducts or impaired flow in intrahepatic ducts

Question 36

Cholelithiasis

Answer 36

formation of stones w/in the GB or biliary duct system | can cause cholecystitis (inflam of GB) and cholangitis (inflam of biliary ducts)

Question 37

Factors causing the formation of gall stones

Answer 37

1) too much abs of water from bile 2) too much abs of bile acids from bile 3) too much cholesterol in bile 4) inflammation of epi