Endocrine Pancreas Flashcards

1
Q

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

A

True.

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2
Q

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

A

In the core

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3
Q

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

A

Beta cells. (60-65%)

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4
Q

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

A

Tend to be located near the periphery of the islet

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5
Q

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

A

delta cells

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6
Q

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

A

gap junctions

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7
Q

Incoming blood to the I of L goes where first?

A

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

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8
Q

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

A

True

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9
Q

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

A

C peptide.

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10
Q

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

A

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

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11
Q

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

A

C peptide

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12
Q

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

A

GLUT 2

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13
Q

What the steps in releasing insulin?

A
  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.
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14
Q

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

A

Inward-rectifier K channels.

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15
Q

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

A

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

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16
Q

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

A

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.

17
Q

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

A

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

18
Q

somatostain works via what signaling pathway to inhibit insulin secretion.

A

Gi–> inhibit AC.

19
Q

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

A

Gs –> AC –> cAMP–> PKA

20
Q

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?

A

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

21
Q

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

A

mTORC1

22
Q

Which organs need GLUT4 to uptake glucose?

A

adipose tissue and skeletal muscle.

23
Q

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

A

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

24
Q

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

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

All decreases

25
Q

What are the actions of insulin in the liver?

A
  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
26
Q

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
A
  1. increase
  2. increase
  3. increase
  4. Increase
  5. Increase
  6. decrease
  7. Decrease
  8. Increase
27
Q

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
A
  1. Increase
  2. Increase
  3. Increase
  4. Increase
  5. Decrease
  6. Increase
28
Q

What are some stimulatory factors for insulin secretion?

A
  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
29
Q

What are some factors that inhibit insulin secretion?

A
  1. decreased blood glucose
  2. Fasting
  3. Exercise
  4. Somatostatin
  5. alpha adrenergic agonist
  6. Diazoxide
30
Q

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
A
  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
31
Q

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

A
  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
32
Q

What are some treatment options for DM type II?

A
  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.
33
Q

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

A

Secretin and GIP

34
Q

What are the stimulatory factors of glucagon release?

A
  1. Low blood glucose
  2. increased AA esp arg and Ala
  3. Fasting
  4. CCK
  5. B-adrenergi agonist
  6. ACh
35
Q

What are some inhibitory actions of glucagon?

A
  1. insulin
  2. Somatostatin
  3. increased FA and Ketoacid concentration
36
Q

What are the actions of Glucagon?

A

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.
37
Q

Glucagon acts via what signaling pathway?

A

Gs

38
Q

What is incretin and what are its actions?

A

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

39
Q

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

A

decreased