Endocrine Pancreas

Question 1

True or False. Endocirne cells of the pancreas in the islets of langerhans are innervated by adrenergic, cholinger, peptidergic and neurons.

Answer 1

True.

Question 2

Where on the islets of langerhans are the beta cells mainly located?

Answer 2

In the core

Question 3

What is the predominantly cell type int he islet of hangerhan?

Answer 3

Beta cells. (60-65%)

Question 4

Where are the alpha cells located in the islet of langerhan?

Answer 4

Tend to be located near the periphery of the islet

Question 5

Which cell types have a neuronal appearance and send dendrite-like processes to beta cells.

Answer 5

delta cells

Question 6

How do the cells of the I of L communicate with each other?

Answer 6

gap junctions

Question 7

Incoming blood to the I of L goes where first?

Answer 7

to the center of the islet, to the beta cells.

Question 8

True or false, cells of the I of L have both endocrine and paracrine activitty.

Answer 8

True

Question 9

In the Golgi, insulin is packaged in vesicle with what _

Answer 9

C peptide.

Question 10

In the secretory vesicle when insulin is packaged, is the C peptide attached to the insulin?

Answer 10

No. C peptide gets cleaved in the Golgi and is packaged with insulin.

Question 11

In patients receiving insulin injections, what can be measured to test Beta cell function in type I diabetes?

Answer 11

C peptide

Question 12

In the beta cells, glucose binds to what type of receptor?

Answer 12

GLUT 2

Question 13

What the steps in releasing insulin?

Answer 13

1. Glucose binds to GLUT2 and comes inside the beta cell.
2. Glucose undergoes glycolysis
3. ATP is produced
4. Increased ATP inside the cell closes K+ channels.
5. Cells become depolarized
6. Depolarization causes Ca channels to open.
7. Ca comes into the cell and causes insulin+C peptide vesicles to Fuse.
8. Vesicle is exocytosed, and insulin and C peptides are released.

Question 14

What type of K channels are found on the pancreatic beta cells which closes due to increased intracellular ATP levels.

Answer 14

Inward-rectifier K channels.

Question 15

Pancreatic beta cells also contain sulfonyurea receptor which is an important receptor clinically because _

Answer 15

Sulfonylurea drugs (e.g. tolbutamide, glycburide) promotes the closing of ATP-dependent K channels which increases insulin secretion. This is used as a tx for type II DM

Question 16

C peptide is secreted in equimolar amount of insulin. How does it change before it can get excreted through urine.

Answer 16

It is excreted unchanged in urine; that is why it’s measurement is a good screening test to test the function of endogenous beta cells.

Question 17

CCK, ACh works via which signaling pathway to modulate insulin release?

Answer 17

Gq–>PLC –>IP3 and DAG. IP3 goes to ER and increase Ca. DAG goes to PKC. Both helps to release insulin.

Question 18

somatostain works via what signaling pathway to inhibit insulin secretion.

Answer 18

Gi–> inhibit AC.

Question 19

Glucagon (GLP-1) uses which signaing pathway to secrete insulin.

Answer 19

Gs –> AC –> cAMP–> PKA

Question 20

Insulin receptor works via two pathways: RAS dependent and RAS independent. In the RAS dependent pathway, which effect of insulin is predominant metabolic, or growth effects?

Answer 20

growth effects. Ras independent pathway leads to the metabolic effects.

Question 21

Insulin can self regulator it’s own receptor. what intactivates the IRS?

Answer 21

mTORC1

Question 22

Which organs need GLUT4 to uptake glucose?

Answer 22

adipose tissue and skeletal muscle.

Question 23

Which cells/organ do not need insulin to uptake glucose?

Answer 23

Brain, RBC, Intestine, cornea, kidney, and liver

Question 24

Due to insulin, how to the levels of the following change in the blood?

1. Glu
2. FA
3. KA
4. AA
5. K+

Answer 24

All decreases

Question 25

What are the actions of insulin in the liver?

Answer 25

1. Increase glucokinase activity 2. Increase glycogen synthesis 3. decrease glucose release 4. decrease gluconeogeenesis) 5. Increase Glycolysis (inc. Acetyl CoA and FA synthesis) 6. Increase TG storage and export in VLDL 7. Inc. protein synthesis, and decrease protein degration

Question 26

Do the following increase or decrease in response to insulin in the adipose tissue. 1. GLUT4 transporters, 2. Glycolysis 3. a-glyerol phosphate 4. Acetyl CoA, FA syn 5. TG 6. HPL 7. Lipolysis 8. Lipoprotein lipase, and uptake

Answer 26

1. increase 2. increase 3. increase 4. Increase 5. Increase 6. decrease 7. Decrease 8. Increase

Question 27

How does the following change (increase or decrease) in response to insulin in the muscle? 1. GLUT4 transporter 2. Glycogen synthesis 3. glycolysis 4. Protien synthesis 5. Protein degradation 6. TG

Answer 27

1. Increase 2. Increase 3. Increase 4. Increase 5. Decrease 6. Increase

Question 28

What are some stimulatory factors for insulin secretion?

Answer 28

1. Increased Glucose 2. Increased AA 3. Increased FA and KA 4. Glucagon 5. Cortisol 6. GIP 7. Vagal stimulation;Ach 8. K 9. Sulfonylurea Drugs 10. Obesity

Question 29

What are some factors that inhibit insulin secretion?

Answer 29

1. decreased blood glucose 2. Fasting 3. Exercise 4. Somatostatin 5. alpha adrenergic agonist 6. Diazoxide

Question 30

In diabetes mellitus type 1. do the following increase or decrease: 1. Blood glucose 2. Glucose uptake 3. Glucose utilization 4. Gluconeogenesis 5. Blood FA, and KA 6. FA synthesis 7. TG synthesis 8. TG breakdown 9. level of circulating free FA 10. Conversion of FA to KA 11. blood AA 12. Protein breakdown 13. Protein synthesis 14. Catabolism of AA 15. Ureagenesis

Answer 30

1. increase 2. decrease 3. decrease 4. increases 5. Increases 6. Decreases 7. Decreases 8. Increase 9. Increases 10. Increases 11. Increases 12. Increases 13. Decreases 14. Increases 15. Increases

Question 31

What some causes of obesity-induced insulin resistance as seen in TYPE II DM.

Answer 31

1. decrease GLUT4 uptake of glucose in response to insulin release 2. Decrease ability of insulin to repress hepatic glucose production 3. inability of insulin lipase or increase lipprotien liase in adipose tissue

Question 32

What are some treatment options for DM type II?

Answer 32

1. caloric restriction and weight reduction 2. Insulin secretagogues like sulfonylurea drugs and incretin analog of GLIP-1 (exenatide) 3. Slow absorption of carbohydrates drugs like a-glucosidase inhibitors (acarbose, miglitol); or amylin analogs (pramlintide) 4. Insulin sensitizers: Biguanide drugs (metformin): upregulate insulin receptors on target tisues.

Question 33

Glucagon comes from the same family or hormone that makes what GI hormones?

Answer 33

Secretin and GIP

Question 34

What are the stimulatory factors of glucagon release?

Answer 34

1. Low blood glucose 2. increased AA esp arg and Ala 3. Fasting 4. CCK 5. B-adrenergi agonist 6. ACh

Question 35

What are some inhibitory actions of glucagon?

Answer 35

1. insulin 2. Somatostatin 3. increased FA and Ketoacid concentration

Question 36

What are the actions of Glucagon?

Answer 36

increase blood glucose by: 1. Increase glucogenolysis and inhibit glycogen formation 2. Increase gluconeogenesis by increase the production of fructose 2,6 bisphophate 3. Increase lipolysis and inhibits FA synthesis, which shunts substrate toward gluconeogenesis.

Question 37

Glucagon acts via what signaling pathway?

Answer 37

Gs

Question 38

What is incretin and what are its actions?

Answer 38

It's an intestine derived hormones like GLP, GIP, which are secreted in response to GI glucose and fat. It stimulates insulin secretion, inhibit glucagon secretion and slows gastric emptying

Question 39

In diabetics, would you expect incretin to be inceased or decreased?

Answer 39

decreased