Insulin and glucose regulation

Question 1

What are the four types of cells found in the pancreas?

Answer 1

Beta cells, alpha cells, delta cells and PP cells

Question 2

What do delta cells secrete?

Answer 2

Somatosatin

Question 3

What do PP cells secrete?

Answer 3

Pancreatic polypeptides

Question 4

What is the endocrine function of the pancreas?

Answer 4

To produce hormones and transport secreted hormones to the portal vein

Question 5

What is insulin initially produced as?

Answer 5

Proinsulin

Question 6

What are the three domains of proinsulin?

Answer 6

aminoterminal β-chain, carboxyterminal α-chain and
the connecting inactive C-peptide.

Question 7

What kind of bond holds the proinsulin together?

Answer 7

disulphide

Question 8

What is the half life of insulin?

Answer 8

5-8 minutes, it is then metabolised in the liver and kidney

Question 9

What mineral causes insulin secretion?

Answer 9

influx of calcium causes a release of insulin via exocytosis

Question 10

What is the name of the protein that transports glucose?

Answer 10

GLUT

Question 11

What is the first phase of the biphase response?

Answer 11

pre-formed insulin is released (this is very quick)

Question 12

What is the second phase of biphase?

Answer 12

The more prolonged phase due to the synthesis of new insulin

Question 13

What hormone produced in the GIT secretes insulin?

Answer 13

GIP

Question 14

What does an increase in amino acids lead to?

Answer 14

An increase in insulin and therefore an increase in protein synthesis

Question 15

What are that target cells for glucose storage?

Answer 15

hepatocytes, myocytes and adipocytes

Question 16

Why does insulin increase uptake of amino acids

Answer 16

Hepatic gluconeogenesis requires amino acids

Question 17

What is the primary organ of glucagon?

Answer 17

The liver, it metabolises glucose from hepatic glycogen and gluconeogenesis

Question 18

Where is glucagon metabolised?

Answer 18

In the liver and the kidney, it has a half life of 5-6 minutes

Question 19

What is the correlation between increased levels of AA and glucagon

Answer 19

it increases the levels of glucagon

Question 20

What is the anticipatory release of GIP?

Answer 20

Insulin resposne is greater when glucose is ingested orally as there is an anticipatory release of GIP when it knows that food is going to be ingested

Question 21

What is the effect of glucagon on protein metabolism?

Answer 21

Increases the levels of protein degredation into amino acids (which are needed for gluconeogenesis)

Question 22

What is GLUT-4 and where is it found primarily?

Answer 22

insulin-regulated glucose transporter and it is found primarily in adipose tissue and striated muscle

Question 23

What is glucose nadir?

Answer 23

The lowest levels of glucose during a days set point/ the glucose baseline

Question 24

How does GIP work?

Answer 24

after eating, GIP travels through the circulation to the beta cells to increase the release of insulin

Question 24

How does GIP work?

Answer 24

after eating, GIP travels through the circulation to the beta cells to increase the release of insulin

Question 25

What nervous system increases secretion of insulin?

Answer 25

Increased activity in parasympathetic nerve fibres in the vagus nerve (autonomic nervous system)

Question 26

What are the target cells of insulin?

Answer 26

adipocytes, hepatocytes and myocytes

Question 27

What is the exocrine function of the pancreas?

Answer 27

Pancreatic juice

Question 28

What are some of the things that trigger insulin secretion into the blood?

Answer 28

Increased glucose and amino acid levels in the plasma

Question 29

What is a GLUT-4 transporter?

Answer 29

Increases uptake of glucose to skeletal muscle/ striated muscle