Bile Flashcards
What is bile made up of?
bile salts cholesterol xenobiotics (drugs, alcohol) electrolytes (HCO3- mainly) phospholipids (lecithin) bilirubin
What cells is bile secreted by and how often?
in the liver by hepatocytes
continuously
What is bile used to do?
emulsify fats
Where is bile stored and concentrated?
In the gall bladder since NaCl and water are absorbed into the blood
Where does the gall bladder lie?
Lies in the junction of the right mid clavicular line & costal margin
How is the liver connected with the GI tract in regards to veins?
superior mesenteric vein drains into the portal vein to liver
What is the portal triad?
A hepatic portal vein
Hepatic artery
Bile duct
What is in the centre of the hepatic lobule?
Central vein eventually becomes the hepatic vein
Where do substances absorbed from the small intestine end up in the liver?
In the hepatic sinusoid (type of BV, with fenestrated discontinuous endothelium)
Where does majority of the livers blood supply come from?
Portal vein - 80%
Hepatic artery - 20%
What is the pathways of bile?
Bile canaliculi, bile ductules, left & right hepatic duct, common hepatic duct, Cystic duct from gall bladder joins, common bile duct
Where does the common bile duct go to?
Ampulla of vater
Opening into duodenum
What other duct is found at the ampulla of vater?
Pancreatic duct
What sphincter is found at the ampulla of vater and what does it do?
Sphincter of oddi
Regulates entry of bile and pancreatic substances into the duodenum
Where do the 2 ducts enter?
Enter the duodenum at the major duodenal papilla (2nd part of duodenum)
Where does the hepatic bile enter the gallbladder from?
What does the gall bladder do to it?
Via the cystic ducts
Stores and concentrates it
Bile remains in the gall bladder until…. Which is caused by?
Contracts
Under the action of CCK (cholecystokin)
It is released due to the presence of AA and FA in duodenum
What blood vessels supply and drain blood from gall bladder?
Cystic artery, blood to gallbladder
No venous drainage
What % of bile salts are reabsorbed and are excreted?
95% reabsorbed
5% excreted in faeces
Where are bile salts reabsorbed?
In Jejunum (some) and terminal ileum (mostly)
What is the pathway of bile salts going from the terminal ileum to the liver, including channels?
using apical Na+ - bile acid transporter
Into the portal vein
Then into the hepatocytes by 2^ active transport coupled to Na+
The liver synthesis new bile salts from…. To replace the small amount that escaped
Cholesterol
The liver secretes….. extracted from the blood into bile
Cholesterol
Cholesterol homeostasis in the blood is controlled by?
Bile secretion
Excretion of cholesterol in the faeces
