Flashcards in disorders of the gallbladder and biliary tract Deck (73)
Which way does blood flow in the liver? Bile?
Blood flows from portal veins-->central vein
Bile flows from the central vein-->bile ducts
Which zone is first affected by toxic injury? ischemia?
Zone I: portal area = toxic injury
Zone 3: central vein = ischemia
What are sinusoids?
fenestrated capillaries allowing macromolecules in blood to contact hepatocytes through the space of Disse
What prevents bile from exiting the bile canaliculus in between the hepatocytes and accessing the sinusoids?
tight gap junctions
Bile secretion i an active process. What does it depend on?
3. interaction of bile with secretory apparatus
4. Permeability of bile canaliculus
What is the only mechanism for cholesterol excretion?
What is in bile?
What is a conjugated bile acid?
Adding an AA (glycine or taurine) to a bile acid which makes is amphiphilic
Where does bilirubin come from? How is it conjugated?
80% of bilirubin comes from erythrocytes. Glucoronyl transferase adds a glucoronic acid to conjugate it.
What do the ducts and ductules do?
Modify the bile by adding HCO3 and water
What is the purpose of the gallbladder?
Concentrates the bile
What elements are concentrated in the gallbladder?
Why do you need an acidic pH for the gallbladder?
Otherwise, CaCO3 will precipitate
What do the bile salts form? Why is this essential?
Micelles. These are essential for digestion, transport, and absorption of fat soluble vitamins (ADEK)
What is contained in micelles? Vesicles?
Micelles: bile acid+cholesterol+phospholipids
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
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
What is the total bile flow/day?
150mL=water/salts from the ducts
What are the main functions of bile?
Absorption of fat soluble vitamins
Cholesterol waste elimination
Which portion of the digestive system has lots of micelles?
Where are most of the bile acids resorbed back into the blood?
Within the ileum (95%)
What are the names of the secondary bile acids? What produces them?
How much of bile acids arrive in the colon?
What would cause a rise in unconjugated bili (indirect), generally?
1. Overproduction of bili
2. Defective uptake
3. Defective conjugation
What would cause a rise in conjugated (direct) bili?
defective excretion of bilirubin (extrahepatic)
Low levels of glucuronyl transferase (High indirect bili)
Crigler-Najar (type I/type II)
Type I: no GT
Type II: Very low GT
-->In both cases, high indirect bili
Which hereditary condition results in high direct bili?
Dubin Johnson and Rotor syndrome
What is cholestasis?
Blockage in bile flow