Jaundice Ebook Flashcards
Where do liver cells first excrete bile?
Into canaliculi
What are canaliculi?
intercellular spaces between the liver cells
Where do canaliculi drain?
right and left hepatic ducts, after which bile travels via the common hepatic and cystic ducts to the gall bladder.
Function of the gallbladder?
concentrate the bile 10 fold by removing water and stores bile until a person eats
Describe the exretion of bile
Bile is discharged from the gallbladder via the cystic duct into the comon bile duct and then into the duodenum, where it begins to dissolve the fat ingested by food
Blood supply (oxygenated blood) to the gallbladder?
cystic artery and is usually a branch of the right hepatic artery. When the cystic artery reaches the neck of the gallbladder, it divides into anterior and posterior divisions
Venous supply (draining) for the gallbladder?
small veins that either directly enter into the liver, or, rarely to a large cystic vein that carries blood back to the portal
What is a HIDA scan (also called hepatobiliary scintigraphy, cholescrintigraphy, hepatobiliary scan)?
A HIDA scan is an imaging procedure that helps track the production and flow of bile from your liver to your small intestine.
Describe process of HIDA scan
Technetium-99m-labeled iinodiacetic acid analogs (new class of organic anion) are taken up and secreted by hepatocyte into hepatic bile by a carrier-mediated organic anion system. The amount of uptake and the rapidity of its elimination from the liver is dependent upon the structural configuration of the agent as well as the function integrity of the hepatocyte and the patency of the biliary system. (essentially you are tracking the movement of a labeled molecule that mimics bile, checking for any obstruction to flow using special imaging)
Can the body metabolize cholesterol to simpler constituent (CO2, H2O, etc.)
Naw
How does the body eliminate cholesterol?
The only mechanism the body possesses to eliminate cholesterol is via the bile acids (and their derivatives, the bile salts) in the feces
What are the primary bile acids?
Cholic acid and chenodeoxycholic acid ; these are the initial products of bile-targeted cholesterol metabolism in the liver
What enzyme is the rate limiting step catalyzed by in bile synthesis?
7-alpha-hydroxylase (CYP7alpha)
How are bile acids different from cholesterol?
24 carbon atoms, amphipathic nature, presence of two or three -OH groups, and negative charge
How are primary bile acids further modified?
The primary bile acids are further modified with amide linkages of glycine or taurine to the ring’s carboxyl group, to produce the primary bile salts, glycocolic acid and taurocholic acid
(Why make these modifications? enhance their hydrophilicity/lower pka)
Which verison of bile salts enter circulation?
The modified primary bile salts (glcocolic and taurocholic acid) enter the enterohepatic circulation
Where are the glycine and taurine residues removed? Why does this matter? How does it?
- in the colon
- allows for passive uptake of bile acids
- bacteria in the gut (specifically the colon)
What is cholelithiasis?
The precipitation or crystallization of cholesterol if more cholesterol enters the bile than can be excreted
What causes cholelithiasis
caused by a decrease of bile acids in the bile
What can cause a decrease in bile acids in bile?
(1) gross malabsorptionof bile acids from the intestine; seen in patients with severe ileal disease
(2) obstruction of the biliary tract
(3) sever hepatic dysfunction, leading to decreased synthesis of bile salts, or other abnormalities in bile production
(4) excessive feedback suppresion of bile acid synthesis as a result of an accelerated rate of recycling of bile acids
Recommend treatment of asymptomatic gallstones?
Surgical treatment of asymptomatic gallstones without medically disease is discourage. Approximately 25% of patients with gallstones develop symptoms within 10 years. The risk of complications arising from interventions is higher than the risk of symptomatic disease.
(I think this is saying to not do anyting if it is asymptomatic).
When is removal of the gallbladder recommended?
Removal of the gallbladder (cholecystectomy) is generally indicated in patients who have experienced symptoms or complications of gallstones, unless the patient’s age and generalhealth make the risk of surgery prohibitive.