lecture 11: liver structure/fxn Flashcards Preview

GI > lecture 11: liver structure/fxn > Flashcards

Flashcards in lecture 11: liver structure/fxn Deck (27):
1

what are the central metabolic functions of the liver?

carbohydrate metabolism
fat metabolism
protein metabolism + synthesis

2

describe carbohydrate metabolism

gluconeogenesis
synthesis + storage of glycogen
conversion of galactose and fructose into glucose

3

describe fat metabolism

fatty acid oxidation
lipid synthesis
alcohol

4

describe protein metabolism/synthesis

plasma protein synthesis (albumin, clotting factors)
amino acid synthesis
urea formation

5

what are other key liver functions?

bile formation
waste formation + excretion into bile
immune functions
storage/modification of vitamins + iron

6

what does the portal triad contain?

portal vein
bile duct
hepatic artery

+ lymphatic vessels + branches of vagus nerve

7

where does blood flow from hepatic portal vein and the branch of hepatic artery in the portal triad?

both flow into liver

8

what are the functional units of the liver?

classic hepatic lobule
portal lobule
liver acinus

9

how frequently is each functional unit of the liver used?

classic hepatic lobule = most common
portal lobule = rarely used
liver acinus = sometimes used

10

Describe functional units of liver

classic hepatic lobule: drains blood from portal vein + hepatic artery to hepatic or central vein
portal lobule: drains bile from hepatocytes to the bile duct
liver acinus: supplies oxygenated blood to hepatocytes

11

compare the centers and fluids of each functional unit of the liver

classic hepatic lobule:
center = outflow; fluid = venous blood

portal lobule:
center = outflow; fluid = bile

liver acinus:
center = inflow; fluid = portal + arterial blood

12

what is the liver acinus supplied by?

branches of hepatic artery

13

which zone of liver acinus are hepatocytes least oxygenated?

zone III (closest to central/hepatic vein)

14

What are the major cell types in the liver? what is their function?

hepatocytes = multiple metabolic/biosynthetic functions
endothelial cells = barrier b/w blood + hepatocytes, CL of macromolecules
stellate (ito) cells = retinoid storage, release; liver growth, regeneration, cirrhosis
Kuupffer cells: resident macrophages
biliary epithelial cells

15

describe localization of liver cell types relative to sinusoids

sinusoids are lined by endothelial cells.
kupffer cells flow through sinusoids, while stellate cells sit between endothelial cell and hepatocytes

16

describe the polarization of hepatocytes

3 functional sides:
1) basal area exposed to perisinusoidal space
2) lateral contact w/ other liver cells
3) apical area exposed to biliary canaliculi

17

do the endothelial cells have filtration barriers for blood?

no, just for cells

18

what is the perisinusoidal space?

extracellular space between fenestrated sinusoidal endothelium and the basolateral side of hepatocytes

19

where are Ito/hepatic stellate cells (HSC) located?

perisinusoidal space

20

what do activated HSC cells produce?

extracellular matrix which is important for normal liver regeneration (but also cirrhosis development)

21

where are kupffer cells located?

located within sinusoids and in contact with endothelial cells

22

what are functions of the biliary tract?

(1) conduit for bile from liver to small intestine
(2) bile modification and storage

23

describe the functions of biliary tract

(1) efficient lipid digestion and absorption requires bile acids for micelle formation
(2) bile modification: gallbladder inc. [bile] and decreases [Cl, HCO3]; gallbladder will contract with meal ingestion to provide bile for fat digestion/absorption

24

what are the biliary canaliculi formed by?

apical sides (microvilli) of two adjacent hepatocytes

25

what are the name of the biliary duct epithelial cells?

cholangiocytes

26

what is missing from gallbladder histology?

muscularis mucosa and submucosa
villi, goblet and paneth cells

27

what forms the ampulla?

common bile ducts, pancreatic duct and part of sphincter of Oddi