Flashcards in 9. Liver & Pancreas Deck (19):
Bile from the liver & pancreatic secretions enter the duodenum via a common duct.
True or False?
What happens if the sphincter of Oddi is closed?
Bile is stored in the gall bladder
What is the Ampulla of Vater?
A small bulge where the common duct enters the duodenum.
(important for endoscopy)
Where is gastrin produced and what is its main function?
G-cells in stomach
Stimulates acid secretion
Where is CCK produced and what stimulates its release?
I-cells in small intestine (mainly duodenum)
Lipids & peptides in SI
Where is secretin produced and what stimulates its release?
S-cells in small intestine
Acid in small intestine
What are the main effects of CCK?
1. Stimulates pancreatic secretion.
2. Stimulates emptying of gall bladder
CCK secretion is described as being positive feedback under the control of a negative feedback system.
How does CCK secretion stop?
Once trypsin has finished acting on peptides in food, it breaks down the releasing factor and monitor peptides acting on the I-cells which stops further secretion of CCK
What is the main function of secretin?
Neutralise acid in small intestine by stimulating bicarbonate secretion.
Also slightly inhibits acid production (gastrin) in stomach.
What is the function of bile salts?
Break down big fat droplets by dissolving them
Why does bile have a dark colour?
Breakdown of haemoglobin releases dark pigment
Outline the order of haemoglobin break down and two ways the product can be removed.
Spleen = haemoglobin -> bilirubin
Liver = bilirubin -> conjugated bilirubin
1. Excreted in faeces.
2. Converted to urobilinogen which can either be excreted or removed in urine.
What is special about sinusoids in liver?
Vessel which contains arterial and venous blood is mixed together.
Allows hepatocytes to process food from gut and also have an oxygen supply.
The gall bladder absorbs salt + water from bile so that it can store a high concentration of bile salts in a small volume.
How does the fluid remain isotonic so that this is safe?
Bile components form a precipitate of micelles which has a small effect on water potential.
Where do hepatocytes actively secret bile components into?
How can bile salts be reabsorbed?
Bile salts must be decongugated to be reabsorbed.
1. Some is passively reabsorbed in small intestine.
2. Most is reabsorbed in ileum by co-transporters.
3. Bacteria can deconjugate bile salts allowing passive reabsorption in colon.
Return via portal circulation to liver for recycling.
Proteases secreted by the pancreas are all precursors.
True or False?
What types of enzymes are secreted by the pancreas?
Monitor peptide (CCK production)