9. Liver & Pancreas

Question 1

Bile from the liver & pancreatic secretions enter the duodenum via a common duct.
True or False?

Answer 1

TRUE

Question 2

What happens if the sphincter of Oddi is closed?

Answer 2

Bile is stored in the gall bladder

Question 3

What is the Ampulla of Vater?

Answer 3

A small bulge where the common duct enters the duodenum.

important for endoscopy

Question 4

Where is gastrin produced and what is its main function?

Answer 4

G-cells in stomach

Stimulates acid secretion

Question 5

Where is CCK produced and what stimulates its release?

Answer 5

I-cells in small intestine (mainly duodenum)

Lipids & peptides in SI

Question 6

Where is secretin produced and what stimulates its release?

Answer 6

S-cells in small intestine

Acid in small intestine

Question 7

What are the main effects of CCK?

Answer 7

1. Stimulates pancreatic secretion.

2. Stimulates emptying of gall bladder

Question 8

CCK secretion is described as being positive feedback under the control of a negative feedback system.
How does CCK secretion stop?

Answer 8

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

Question 9

What is the main function of secretin?

Answer 9

Neutralise acid in small intestine by stimulating bicarbonate secretion.
Also slightly inhibits acid production (gastrin) in stomach.

Question 10

What is the function of bile salts?

Answer 10

Break down big fat droplets by dissolving them

Question 11

Why does bile have a dark colour?

Answer 11

Breakdown of haemoglobin releases dark pigment

Question 12

Outline the order of haemoglobin break down and two ways the product can be removed.

Answer 12

Spleen = haemoglobin -> bilirubin
Liver = bilirubin -> conjugated bilirubin

1. Excreted in faeces.
2. Converted to urobilinogen which can either be excreted or removed in urine.

Question 13

What is special about sinusoids in liver?

Answer 13

Vessel which contains arterial and venous blood is mixed together.
Allows hepatocytes to process food from gut and also have an oxygen supply.

Question 14

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?

Answer 14

Bile components form a precipitate of micelles which has a small effect on water potential.

Question 15

Where do hepatocytes actively secret bile components into?

Answer 15

Bile canaliculi

Question 16

How can bile salts be reabsorbed?

Answer 16

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.

Question 17

Proteases secreted by the pancreas are all precursors.

True or False?

Answer 17

TRUE

for safety

Question 18

What types of enzymes are secreted by the pancreas?

Answer 18

Proteases
Pancreatic a-amylase
Lipases
Nucleases
Monitor peptide (CCK production)

Question 19

Why are people with cystic fibrosis more likely to get pancreatitis and pancreatic failure?

Answer 19

CFTR channels do not work, therefore Cl- is not secreted into the pancreatic duct.
This means that Na+ and water do not enter the duct.
Resulting in very thick + sticky secretions which are trapped in pancreas.