Endocrinology 20

Question 1

What does Somatostatin do?

Answer 1

Inhibits the release of insulin and glucagon in the pancreas through paracrine action because it acts on itself

Question 2

What do the beta cells do?

Answer 2

Produce, store, and release insulin

Question 3

What happens to the beta cells when there is increased blood glucose level? (Steps)

Answer 3

The glucose enters the beta cell through GLUT channels and is metabolized so it increases the production of ATP and increases the ATP to ADP ratio. This causes a closure of potassium channels causing the level of potassium in the cell to increase causing depolarization of the membrane and depolarization of voltage-gated calcium channels causing an increase in insulin secretion

Question 4

What happens to the beta cells when there is decreased blood glucose level?

Answer 4

Decreased glucose enters the cell which doesn’t get metabolized so it doesn’t increase the ATP/ADP ratio so potassium channels don’t close and lead to depolarization and secretion of insulin

Question 5

What are the four types of stimuli that insulin and glucagon can be controlled by?

Answer 5

• Nutrients in the blood
• Hormones from GIT
• Role of local islet hormones
• Role of nerves

Question 6

What happens to insulin if there is increased levels of glucose in the blood?

Answer 6

Insulin secretion is increased

Question 7

What happens to glucagon if there is increased levels of glucose in the blood?

Answer 7

There are decreased levels of glucagon

Question 8

How do amino acids affect the levels of insulin and glucagon in the blood?

Answer 8

Increased amino acids increase the level of glucagon and insulin in the blood

Question 9

How do incretins secrete from the GI tract affect the secretion of Insulin and Glucagon?

Answer 9

They increase the secretion of insulin and depends on the type of incretin for glucagon

Question 10

What are the islet cell hormones?

Answer 10

Somatostatin
Insulin
Glucagon

Question 11

How does Somatostatin affect insulin and glucagon?

Answer 11

It decreases secretion of insulin and glucagon

Question 12

How does Insulin affect glucagon?

Answer 12

It decreases the levels of glucagon in the blood

Question 13

How does Glucagon affect insulin?

Answer 13

It increases the level of insulin

Question 14

How do parasympathetic nerves affect insulin and glucagon?

Answer 14

They increase insulin and don’t affect glucagon

Question 15

How do sympathetic nerves affect insulin and glucagon?

Answer 15

They increase glucagon and depend on what type of receptor for insulin

Question 16

Why do amino acids increase glucagon secretion?

Answer 16

Because a rise in amino acids increases blood insulin which will decrease blood glucose. This decrease in blood glucose causes an increase in glucagon