L17: Liver and Pancreas

Question 1

blood flow thru the liver lobule

Answer 1

portal vein 
sinusoids
central vein
hepatic veins
hepatic artery
sinusoids
central vein
heptaic veins

Question 2

sinusoids of the liver are lined w/ ?

Answer 2

endothelial cells

Kupffer cells

Question 3

_________ is found between endothelial cells and hepatocytes

Answer 3

space of disse

Question 4

describe liver vascular supply (flow, resistance, pressure)

Answer 4

high bld flow
low vascular resistance
27% of CO
portal press = 9
press liver to vena cava = 0

Question 5

effect of cirrhosis on blood flow

Answer 5

increases blood resistance to blood flow

Question 6

effect of clot blocking portal vein or a major branch

Answer 6

blockage of return blood from spleen and intestines

increase in capillary pressure in intestinal wall = loss of fluid = death

Question 7

blood volume in liver

Answer 7

normal = 450 ml
10% of body’s blood

high press in R atrium = backpressure on liver = increased bld vol up to 1.5 L in liver

thus liver can store bld in times of excess and supply bld in times of diminished

Question 8

higher than normal pressure in hepatic veins

Answer 8

back press causes fluid to transude into lymph

fluid leaks thru capsule into abdominal cavity

lg vol of fluid = ascites

Question 9

function of liver in carb metabolism

Answer 9

stores glc as glycogen
convert galactose/fructose to glucose
gluconeogenesis

release stored glc into circulation

Question 10

function of liver in fat metabolism

Answer 10

oxidation of fatty acids for nrg

synthesis of cholesterol, phospholipids, lipoproteins

synthesis of fats from protein and carbs

Question 11

functions of liver in protein metabolism

Answer 11

deamination of AA
urea formation
interconversion of AA from other AA

Question 12

functions of liver

Answer 12

vit storage: A, D, B12
forming coagulation factors
–fibrinogen, prothrombin, factors 7,9,10

detoxification

Question 13

function of liver – detoxification

Answer 13

removal of drugs and hormones

excretes them into bile
excretes Ca into bile

Question 14

bile secretion – properties

Answer 14

is secreted continuously by hepatocytes in liver and stored in gall bladder until needed

presence of fatty food in duodenum stim release of bile

Question 15

in the gallbladder, how is bile concentrated ?

Answer 15

by active transport of Na followed by secondary absorption of Cl, water

Question 16

synthesis of bile salts by liver

Answer 16

are amphipathic

orient themselves around lipid droplets = emulsification

Question 17

functions of bile salts

Answer 17

emulsification

form micelles w/ lipids for absorption across intestinal mucosa

Question 18

primary bile acids

Answer 18

hepatocytes use cholesterol to form:

• -cholic acid
• -chenodeoxycholic acid

Question 19

secondary bile salts

Answer 19

bacteria in intestine converts primary bile acids into:
deoxycholic
lithocholic acid

Question 20

bile acid conjugation

Answer 20

conjugated w/ glycine or taurine

electrolytes and water added
cholesterol, phospholipids, pigments and organic molecules

Question 21

what is the major pigment in bile?

Answer 21

bilirubin

Question 22

bilirubin formation – reticuloendothelial system

Answer 22

1. Hb phagocytized by macorphages
2. split into globin and heme
3. heme ring frees iron
4. transferrin transports heme in blood
5. heme converted to biliverdin by heme oxygenase
6. biliverdin converted to free unconjugated bilirubin

Question 23

free bilirubin transport

Answer 23

transported in blood stream attached to plasma albumin

released from albumin w/in liver cells and then conjugated

Question 24

bilirubin formation in liver

Answer 24

1. free bilirubin released from albumin
2. conjugated w/ glucuronic acid 80% via enzyme UDP glucuronyl transferase
   2a. w/ sulfate 10%
   2b. w/ other substances 10%

Question 25

secretion of conjugated bilirubin

Answer 25

via active transport into intestine

or excreted into urine

Question 26

conjugated bilirubin in small intestine

Answer 26

terminal ileum

1. converted to urobilinogen by bacteria
2. oxidated into urobilin stercobilin and secreted in feces

or
2. enters enterohepatic circulation, into the liver and then re-excreted by liver or into urine

Question 27

jaundice

Answer 27

yellowish tint to body tissues

caused by bilirubin in EC fluids

common causes:
increased hemolysis
obstruction of bile ducts
liver damage

Question 28

pancreatic islets

Answer 28

1. alpha
   secretes glucagon
   25%
2. beta
   secrete insulin and amylin
   insulin inhibits glucagon, amylin inhibits insulin secretion
   60%
3. delta
   secrete somatostatin
   –inhibits insulin, glucagon, gastrin

Question 29

communication among islet cells

Answer 29

via gap junctions

• -beta to beta
• -alpha to alpha
• -beta to alpha

via islet portal bld supply
–beta cells to alpha/delta

Question 30

pancreatic digestive enzymes for proteins

Answer 30

trypsin, chymotrypsin, carboxypolypeptidase

trypsin inhibitor is secreted by glandular cells in order to protect pancreas from trypsin

Question 31

pancreatic digestive enzymes for carbs and fat

Answer 31

pancreatic amylase

pancreatic lipase, cholesterol esterase, phospholipase

Question 32

characteristics of pancreatic secretions

Answer 32

high volume, isotonic
high bicarbonate conc
low Cl ions

low flow rates when composed mostly of Na/Cl

high flow rates when composed of Na/bicarb

Question 33

pancreatic acinar cells

Answer 33

produce small volume of pancreatic secretion composed mainly of Na/Cl ions

Question 34

pancreatic ductal cells

Answer 34

secrete bicarbonate
reabsorb Cl
via exchange of the 2

permeable to water, flow of water in makes secretions isotonic