Pancreas liver, hormonal control

Question 1

exopeptidase

Answer 1

An exopeptidase is any peptidase that catalyses the cleavage of the terminal peptide bond; the process releases a single amino acid or dipeptide from the peptide chain.
Depending on whether the amino acid is released from the amino or the carboxy terminal.
Aminopeptidase, an enzyme in the brush border of the small intestine, will cleave a single amino acid from the amino terminal
Carboxypeptidase, which is a digestive enzyme present in pancreatic juice, will cleave a single amino acid from the carboxylic end of the peptide.

Question 2

Endopeptidase

Answer 2

break peptide bonds of nonterminal amino acids

Question 3

Functions of liver

Answer 3

Glycogen storage 
Lipid metabolism 
Transamination
Deamination
Detoxification
Lactate removal 
Heat generation
Iron storage
Bile production

Question 4

Label parts of liver

Answer 4

See hand out

Question 5

What happens in the The Ornithine Cycle

Answer 5

Ammonia is converted to less toxic urea

Question 6

What is the equation for the ornithine cycle

Answer 6

2NH3 + CO2 –> CO(NH2)2 + H2O

Question 7

Draw the ornithine cycle

Answer 7

see notes

Question 8

How does it take place

Answer 8

This takes place via a number of reactions partly in cytosol and partly in mitochondria

Question 9

How is ammonia converted

Answer 9

Converted to urea by addition of carbon dioxide in the ornithine cycle

Question 10

What happens after

Answer 10

Urea passed back into the blood and carried to the kidneys where it’s excreted

Question 11

Why can urea be passed into the bloodv

Answer 11

Urea is less soluble and less toxic than ammonia so it can be passed back into the blood to the kidneys

Question 12

What filters the urea? where is it stored and in what form

Answer 12

The kidneys filter out the urea from the blood and store it as urine in the bladder

Question 13

What is the word formula for the ornithien cycle

Answer 13

Ammonia + carbon dioxide –> urea + water

Question 14

Label pancreas

Answer 14

See hand out

Question 15

What are anicar cells

Answer 15

Cells called acinar cells within the pancreas produce digestive enzymes
Found in small groups surrounding tiny tubules
The tubules join up to make the pancreatic duct
Which carries the pancreatic juice to the duodenum
Over 90% of pancreas related to digestive enzyme production
Pancreatic proteases (such as trypsinogen (precursor for), chymotrypsin and carboxypeptidase) - which help to digest proteins.
Pancreatic amylase - which helps to digest carbohydrates (sugars).
Pancreatic lipase - which helps to digest fat.
Hydrogencarbonate ions make the fluid alkaline

Question 16

Name the cells of the pancreas

Answer 16

see handout

Question 17

Describe Gastrin

Answer 17

• Produced by special cells in the lining of the cardiac region of the stomach.
• Produced in response to the physical stimulation due to presence of food as well as to the chemical stimulation by protein .
• Also can be produced by the anticipation (thought) of eating (nervous stimulation).
• When gastrin is released, it stimulates the production of gastric juice by the gastric glands.
• When there is sufficient gastric juice present, the production of gastrin will stop and then so will the secretion of gastric juice

Question 18

Cholecystokinin (CCK)

Answer 18

Produced by special cells in the lining of the duodenum.
Cholecystokinin is produced by the duodenum in response to the physical presence of chyme, as well as to the chemical presence of fat and protein molecules.
This hormone also goes by the name Pancreozymin.
It controls the release of bile from the liver/gallbladder by contraction of the gall bladder
Along with Secretin, it also stimulates the release of pancreatic juice from the pancreas – mainly the release of pancreatic enzymes.
It also controls the emptying of the stomach.

Question 19

Secretin

Answer 19

Produced by special cells in the lining of the duodenum.
Produced in response to the presence of acidic chyme in the duodenum.
When secretin is released it stimulates the production of sodium bicarbonate by the pancreas and secretion of the pancreatic juice
Sodium bicarbonate neutralizes and buffers the acidic chyme so that the pH changes to neutral - 8
When the pH of the chyme in the duodenum reaches ~8, the production of secretin will stop and so will the release of pancreatic juice containing sodium bicarbonate

Question 20

What stimulates release of bile?

Answer 20

Cholecystokinin (CCK)

Question 21

What stimulates release of sodium bicarbonate?

Answer 21

Secretin

Question 22

What stimulate release of gastric juices?

Answer 22

Gastrin