Endo 2: 4 Komar - Endocrine Pancreas

Front 1

What are the cells of the islets of langerhans in the pancreas? 4

Back 1

1. alpha cells
2. beta cells
3. delta cells
4. F cells (one of these is not like the others...)

Front 2

What do the alpha cells in the islet of langerhans produce? 3

Back 2

1. glucagon- like peptides
2. glucagon
3. proglucagon

Front 3

What do the beta cells in the islet of langerhans produce? 4

Back 3

1. insulin
2. proinsulin
3. C peptide
4. amylin

Front 4

What do the delta cells in the islet of langerhans produce? 1

Back 4

1. somatostatin

Front 5

What do the F cells in the islet of langerhans produce?1

Back 5

pancreatic polypeptide

Front 6

A little look at the pancreas just for shats and giggles...

Back 6

Front 7

Why do scientists use Laser Scanning Cytometry to study the physiology of the pancreas?

Back 7

to access their viability before transplantation

Front 8

Summarize insulin production. 7

Back 8

1. mRNA from the insulin gene contains: 5’ untranslated region,B, C, and A peptide domains; and a 3’UTR.
2. The leader plus the B, C, and A domains make the preproinsulin.
3. During translation of the mRNA, the leader sequence is cleaved in the lumen of the rough endoplasmic reticulum.
4. What remains is the proinsulin, which consists of the B, C, and A domains.
5. In the trans-Golgi, proteases cleave the proinsulin at two sites, releasing the C peptide as well as the mature insulin molecule, which consists of the B and A chains that are connected by two disulfide bonds.
6. The secretory granule contains insulin and the C peptide, as well as proinsulin.
7. These components all are released into the extracellular space during secretion.

Front 9

How is insulin secreted? Oh look another graph... yippee.

Back 9

Front 10

Is more insulin secreted in response to oral or IV glucose?

Back 10

More insulin is secreted with oral glucose b/c of GI hormones released which facilitate beta cell function and insulin secretion. This is called an incretin effect.

Front 11

What happens when glucose is given by IV?

Back 11

Glucose delivered via IV stimulates a biphasic release in insulin. The initial increase is believed to be the secretion of preformed insulin present in beta cells. Then secretion increases again as the cells synthesizes ‘new’ insulin.

Front 12

What is the incretin effect?

Back 12

When glucose is given orally and the GI hormones facilitate beta cell function and insulin secretion

Front 13

What happens when insulin signals? and what determines the cellular response that will happen? (2)

Back 13

- the binding of insulin to its receptor can result in the activation of multiple second messenger systems.
- The amount of insulin that binds and the second messenger systems that are activated dictate the cellular responses that will ensue.

Front 14

Where are the effects of insulin felt the most? 3

Back 14

1. muscles
2. adipocytes
3. liver

Front 15

What does insulin do to muscle tissue? 3

Back 15

1. inc glucose uptake
2. inc protein synthesis
3. dec the breakdown of proteins

Front 16

What effect does insulin have on adipocytes? 3

Back 16

1. inc glucose uptake
2. inc free fatty acid uptake
3. inc triglyceride production

Front 17

What effect down insulin have on the liver? 4

Back 17

1. inc glucose conversion to glycogen
2. dec glycogenolysis
3. inc glycolysis and triglycerie prouction
4. dec gluconeogenesis

Front 18

What is amylin?

Back 18

a 37 amino acid peptide co-secreted with insulin in response to nutrient load

Front 19

What does amylin inhibit? 3

Back 19

1. gastric emptying and gastric acid secretion (area = postrema hindbrain)
2. glucagon secretion
3. food intake - satiety factor (area = postrema)

Front 20

What peptide hormone's receptor is bound to G alpha s?

Back 20

Glucagon

Front 21

What stimulated the secretion of glucagon? 2

Back 21

1. hypoglycemia
2. amino acids

Front 22

What inhibits the secretion of glucagon? 3

Back 22

1. hyperglycemia
2. somatostatin
3. insulin

Front 23

Hypoglycemia and amino acids stimulate what?

Back 23

the secretion glucagon

Front 24

Hyperglycemia, Somatostatin, and insulin inhibit the secretion of..?

Back 24

glucagon.

Front 25

What effects does glucagon have? and where?

Back 25

1. the liver
2. dec glycolysis
3. inc gluconeogenesis
4. inc glycogenolysis
5. inc lipolysis

Front 26

The physiology in normal ppl and pathophysiology in diabetes.

Back 26

Normally a decrease in plasma glucose causes a decrease in β-cell insulin secretion that signals an increase in α-cell glucagon secretion during hypoglycemia. An increase in plasma glucose, among other nutrients, causes an increase in β-cell insulin secretion that prevents an increase in α-cell glucagon secretion in response to those nutrients after a mixed meal. On the other hand, in the setting of β-cell failure in type 1 diabetes and advanced type 2 diabetes, a decrease in plasma glucose cannot cause a decrease in β-cell insulin secretion, and the absence of that signal results in no increase in pancreatic α-cell glucagon secretion during hypoglycemia. Conversely, in the setting of β-cell failure, an increase in plasma glucose, among other nutrients, cannot cause an increase in β-cell insulin secretion, and the absence of that restraining signal results in an increase in pancreatic α-cell glucagon secretion after a mixed meal.

Front 27

What secretes somatostatin and what stimulates its secretion? (3)

Back 27

1. delta cells

1. Glucose
2. Arginine
3. GI hormones

Front 28

What are the somatostatin receptors?

Back 28

- SSTR 1-5, G-protein coupled receptors
- SSTR 5 responsible for dec insulin secretion
- SSTR 2 responsible for neg glucagon and GH

Front 29

What are the 3 effects of somatostatin?

Back 29

1. Slows gastric emptying
2. Decreases gastric secretions
3. Inhibits insulin and glucagon secretion (and GH

Front 30

Back 30

Same graph as earlier but less confusing...