Endocrine action of the Pancreas

Question 1

four types of cells in the endocrine pancreas are

Answer 1

alpha, beta, gamma and theta

Question 2

Distribution of cells in the islets

Answer 2

Beta in the centre while the rest are in the periphery

Question 3

Function of alpha cells

Answer 3

Releases glucagon in response to low glucose to increase BGL

Question 4

Function of beta cells

Answer 4

Releases insulin to decrease blood glucose and restrict lipolysis, gluconeogenesis and promote glycolysis. Also produced amylin which will inhibit glucagon secretion, Delays gastric emptying, Inhibits food intake

Question 5

What is the amylin analgue drug

Answer 5

Pramlitide

Question 6

Function of gamma cells

Answer 6

Releases Somatostatin. Inhibits the release of most proteins, such as insulin/gucagon, acid production and the exocrine pancrease. Thought to prevent overreaction to food intake

Question 7

Function of Theta Cells

Answer 7

Releases Pancreatic Polypeptide which will ○ Inhibits food intake, Increases energy expenditure, restricts gall bladder contraction after a meal.

Question 8

How can the function of the beta cells be enchanced

Answer 8

GLP-1 (from L cells) and GIP (K cells) will be released in response to glucose and Fats in the GIT and will prime beta cells for insulin release

Question 9

Other functions of GLP-1

Answer 9

• Regulates appetite at the CNS
• Inhibits gastric emptying
• Only works if glucose is high
• Will inhibit glucagon secretion
• Promotes Bcells prolif, diff and maturation

Question 10

Other Functions of GIP

Answer 10

• Activates lipoprotein lipase

- Dependent on Glucose levels

Question 11

How is Insulin produced

Answer 11

Translated as one polypeptide chain and cleaved by PC1 and 2 to produe three chains (A,B and C). A and B then connect via sulphur bonds. Then packaged into a vesicle ready to be released

Question 12

What are the mechanisms by which pancreas releases insulin

Answer 12

Glucose enters the cells through Glut2 channels, if levels are higher than usual, then there will be an increased ATP/ADP ratio. This will inhibit K+ channels and consequently open Ca2+ channels. The change in Ca2+ concentration will cause the fusion of vesicles with the membrane and release of insulin

Question 13

What are the different phases in which insulin is released

Answer 13

There is an initial sharp release for 2-5 minutes which is then followed by a sustained release for duration of stimulus

Question 14

How do fats trigger the release of Insulin

Answer 14

Gats are converted to Malonyl Coa and inhibit CPT-1 which leads to insulin secretion. There are also FFA receptors that mediate Insulin release