Bile and Biliary system Flashcards
What effect do bile acids in the blood have on the biliary system
Bile acids via blood stimulate parenchymal secretion
What effect does secretin in the blood have on the biliary system?
Causes liver ductal secretion
What effect does cholecystokinin (CCK) in the blood have on the biliary system?
Gall bladder contraction
Relaxation of the sphincter of Oddi
What effect does the vagal stimulation have on the gallbladder
Causes a weak contraction
What is the relationship between bile flow and liver blood flow
They are independent, at high pO2.
Bile flow is an active process requiring energy
How is biliary pressure affected by blood flow
They are independent
What joins to make the common hepatic duct
the right and left hepatic ducts
What do the right and left hepatic duct join to form
the common hepatic duct
What do the common hepatic duct and the cystic duct join to form
the common bile duct
What joins with the common bile dict and where
The pancreatic duct at the sphincter of oddi at the ampulla of vater
Why is water reabsorbed in the gallbladder
so bile salts are concentrated
Describe the physiology of the reabsorption of water in the gallbladder
Paracellular movt of water by osmotic gradient
Grad. produced by movement of ions into interstitial space
Na+:H+ pump in apical membrane moves protons into lumen and Na+ into cell. Then a 3Na+:2K+ ATPase pump in basolateral membrane brings 3Na+ into interstitial space and 2K+ into cell.
K+ then diffuses back into interstitial space through an ion channel
Chloride ions are pumped in to cell by pump in apical membrane in favour of HCO3- which is pumped out of the cell into the lumen. Then Cl- diffuses out of the cell into the interstitial space.
How are glycerol, short and medium chain fatty acids absorbed?
They pass through the enterocyte and enter the blood capillaries due to their small size
What happens to emulsion droplets arriving in the duodenum from the stomach?
Pancreatic lipases, biliary bile salts, lecithin and cholesterol adsorb to their surface.
What effect does bile salts have on multilamellar micelles
Bile salts transform multilamellar micelles into unilamellar micelles and then into mixed micelles which contain bile salts and mixed lipids
Where and how are bile salts reabsorbed?
In the distal ileum by active transport; and passively throughout the small intestine
What happens to lipids after they have been absorbed in enterocytes?
They are reesterified and apoproteins are added producing chylomicrons which are exported via lacteals into the lymph
Where are apoproteins produced and where are they added to a lipid?
Produced in the RER and added in the SER
Where does the lymph flow to get back into circulation after absorption of chylomicrons?
To the thoracic duct to enter the blood via left subclavian vein
Why does bile secretion require oxygen
Active process
Is bile secretion dependent/independant of biliary blood flow
independent
What is the blood conc of bilirubin which may cause jaundice
> 18mg/ml
Why can glycerol pass through enterocyte
Small size
Why do short and medium chain fatty acids diffuse efficiently into enterocytes
Soluble in extracellular water layer
