Flashcards in disorders of the gallbladder and biliary tract Deck (73)
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1
Which way does blood flow in the liver? Bile?
Blood flows from portal veins-->central vein
Bile flows from the central vein-->bile ducts
2
Which zone is first affected by toxic injury? ischemia?
Zone I: portal area = toxic injury
Zone 3: central vein = ischemia
3
What are sinusoids?
fenestrated capillaries allowing macromolecules in blood to contact hepatocytes through the space of Disse
4
What prevents bile from exiting the bile canaliculus in between the hepatocytes and accessing the sinusoids?
tight gap junctions
5
Bile secretion i an active process. What does it depend on?
1. microvilli
2. cytoskeleton
3. interaction of bile with secretory apparatus
4. Permeability of bile canaliculus
6
What is the only mechanism for cholesterol excretion?
bile
7
What is in bile?
bile salts
phospholipids
cholesterol
bilirubin
ions
8
What is a conjugated bile acid?
Adding an AA (glycine or taurine) to a bile acid which makes is amphiphilic
9
Where does bilirubin come from? How is it conjugated?
80% of bilirubin comes from erythrocytes. Glucoronyl transferase adds a glucoronic acid to conjugate it.
10
What do the ducts and ductules do?
Modify the bile by adding HCO3 and water
11
What is the purpose of the gallbladder?
Concentrates the bile
12
What elements are concentrated in the gallbladder?
Na
Bile acid
pH
13
Why do you need an acidic pH for the gallbladder?
Otherwise, CaCO3 will precipitate
14
What do the bile salts form? Why is this essential?
Micelles. These are essential for digestion, transport, and absorption of fat soluble vitamins (ADEK)
15
What is contained in micelles? Vesicles?
Micelles: bile acid+cholesterol+phospholipids
Vesicles: cholesterol+phospholipids
16
What factors can cause gallstone formation?
1. Increased cholesterol, with decreased bile acids and phospholipids in the gallbladder
2. Decreased contractility of the gallbladder
3. High pH
17
What are the actions of cholescystokinin on the gallbladder?
1. Gb contraction
2. Sphincter relaxation
3. Release of pancreatic enzymes
4. Inhibition of gastric emptying
18
What is the total bile flow/day?
600 ml/day.
450mL=bile salts
150mL=water/salts from the ducts
19
What are the main functions of bile?
Fat digestion
Absorption of fat soluble vitamins
Cholesterol waste elimination
20
Which portion of the digestive system has lots of micelles?
jejunum/ileum
21
Where are most of the bile acids resorbed back into the blood?
Within the ileum (95%)
22
What are the names of the secondary bile acids? What produces them?
deoxycholate
lithocholate
23
How much of bile acids arrive in the colon?
1%
24
What would cause a rise in unconjugated bili (indirect), generally?
1. Overproduction of bili
2. Defective uptake
3. Defective conjugation
25
What would cause a rise in conjugated (direct) bili?
defective excretion of bilirubin (extrahepatic)
26
Gilbert's syndrome
Low levels of glucuronyl transferase (High indirect bili)
27
Crigler-Najar (type I/type II)
Type I: no GT
Type II: Very low GT
-->In both cases, high indirect bili
28
Which hereditary condition results in high direct bili?
Dubin Johnson and Rotor syndrome
29
What is cholestasis?
Blockage in bile flow
30
