Liver, Pancreas, Gallbladder

Question 1

What structures are included in the hepatic functional unit?

Answer 1

sinusoids, central vein, bile duct, arteriole of hepatic artery, portal venule

Question 2

What is included in the portal triad?

Answer 2

branch of portal vein, branch of hepatic artery, bile duct

Question 3

True/False: sinusoids contain only oxygenated blood from the hepatic artery

Answer 3

false, it contains a mixture of oxygenated and deoxygenated blood from hepatic arteriole and portal venule

Question 4

What are kupffer cells? functions?

Answer 4

macrophages, that play an important role in innate immunity

Question 5

What are stellate cells? functions?

Answer 5

perisinusoidal cells/pericytes that store vit A and produce extracellular matrix in response to liver damage

Question 6

Briefly describe the process of lipid absorption

Answer 6

in the small intestinal lumen, bile salts emulsify the lipids, they are then packaged into micelles and transported across the epithelium

Question 7

Describe the life cycle of bile

Answer 7

1. bile flows out of the liver through bile ducts into the gallbladder for storage
2. in response to fat, CCK is released and causes contraction of the gallbladder which releases bile into the duodenum
3. bile salts do their thing with fat and then are recirculated back to the liver via portal vein
4. extraction of bile salts from portal blood by hepatocytes

Question 8

True/False: bile salts function throughout the length of the small intestine, from duodenum to ileum before they are recirculated back to the liver

Answer 8

true

Question 9

What percent of bile salts end up recycled

Answer 9

95%

Question 10

What is the purpose of bile conjugation

Answer 10

reduces the passive reabsorption through the lipid bilayer of cell membranes, they are more water soluble so they stay in the lumen longer

Question 11

How are bile salts reabsorbed in the ileum

Answer 11

they are actively absorbed by Na2+ dependent secondary active transport

Question 12

What are the two primary bile acids

Answer 12

Cholic acid
chenodeoxycholic acid

Question 13

What are the two secondary bile acids

Answer 13

deoxycholic acid
lithocholic acid

Question 14

Where are water and ions added to bile?

Answer 14

bile duct epithelial cells

Question 15

What is the pH of bile? why?

Answer 15

alkaline due to the addition of HCO3- by bile duct epithelium

Question 16

What are the 3 functions of the gallbladder

Answer 16

1. store bile
2. concentrate bile
3. eject bile

Question 17

Why do horses have no gallbladder and ruminants have gallbladder short retention time

Answer 17

Because they have continuous digestion and have bile flowing into the small intestine continuously

Question 18

What are 7 of the essential proteins produces and released by the liver

Answer 18

-Glutathione
-ALB
-Clotting factors
-C reactive proteins
-Carrier proteins
- hormones and prohormones
-apolipoproteins

Question 19

What are the two phases of toxin neutralization in the liver?

Answer 19

Phase I: conversion rxn catalyzed by enzymes (ie cytochrome P450)
Phase II: conjugation of substances

Question 20

what is first pass metabolism

Answer 20

modification of oral drugs by the liver before entering systemic circulation

Question 21

The liver is the only visceral organ with the capacity for ____

Answer 21

compensatory hyperplasia

Question 22

What are the two functions of pancreatic secretion

Answer 22

-HCO3- neutralizes H+ delivered to the duodenum from the stomach
-Enzymes digest carbs, proteins, and lipids into absorbable molecules

Question 23

What is the sympathetic effect on the exocrine pancreas?parasympathetic?

Answer 23

sympathetic inhibits pancreatic secretion
parasympathetic stimulates pancreatic secretion

Question 24

Pancreatic secretion has an enzymatic part and and aqueous component, where are each secreted?

Answer 24

enzymes are secreted by acinar cells and the aqueous component by centroacinar and ductal cells

Question 25

Which enzymes are secreted already active and which are secreted inactive?

Answer 25

amylase and lipase are already active while proteases are inactive

Question 26

True/False: pancreatic secretion is isotonic to plasma?

Answer 26

true, but ionic composition can change

Question 27

Which cells secrete trypsin inhibitor? why?

Answer 27

pancreatic gland cells, as a safeguard against proteases

Question 28

Describe proenzyme activation

Answer 28

trypsinogen and other inactive proteases are secreted into intestine, trypsinogen is converted to trypsin by enteropeptidases, trypsin stimulates more conversation of trypsinogen as well as activates the other inactive proteases

Question 29

Concentration of which ions in the aqueous component of pancreatic secretion are influenced by flow rate and which do not change

Answer 29

HCO3- and Cl- are influenced by flow rate
Na+ and K+ do not change

Question 30

The cephalic and gastric phase of pancreatic secretion are mediated via ___

Answer 30

the vagal nerve

Question 31

the intestinal phase of pancreatic secretion is mediated by ____

Answer 31

both hormonal and neural mechanisms

Question 32

What phase of digestion is most pancreatic juices secreted?

Answer 32

intestinal

Question 33

True/False: pancreatic secretion has three methods of regulation, hormonal, neural, and enteric

Answer 33

false, there are no enteric reflexes

Question 34

What stimulates the release of CCk by the I cells of the duodenal epithelium?

Answer 34

nutrients in the lumen of the small intestine

Question 35

Acinar cells have receptors for what molecules?

Answer 35

Ach and CCK

Question 36

What stimulates the release of secretin by the S cells of the duodenal epithelium?

Answer 36

acidic contents in the lumen of the small intestine

Question 37

What is the function of secretin

Answer 37

stimulate HCO3- rich secretion

Question 38

When is secretin