Endocrine Pancreas Flashcards Preview

Endo/Repro > Endocrine Pancreas > Flashcards

Flashcards in Endocrine Pancreas Deck (21)
Loading flashcards...
1
Q

Cells of Islets Langerhans communicate with each other> How?

A

Gap junctions-rapid cell to cell communication between a-a, b-b, a-b

2
Q

What is the direction of blood flow in Islets of Langerhans?

A

From center to periphery

3
Q

Paracrine actions of Islets of Langerhans work __ _______ of blood flow.

A

in reverse

4
Q

Insulin is a peptide hormone-two chains connected by ______ brigdes.

A

Didulfide

5
Q

Steps in insulin formation

A

Preproinsulin–>Proinsulin–>Insulin+C peptide

6
Q

Proinsuline

A

No signaling peptide
C peptide still attached to insulin
Packaged into secretory granules
Proteases in the granule cleave proinsulin

7
Q

Insulin and cleaved C peptide packaged together in _______ _________ .

A

Secretory vesicles

8
Q

Insulin and C peptide are secreted in ______ quantities into blood.

A

Equimolar

9
Q

_ _________ can be used as a marker of endogenous insulin secretion.

A

C peptide

10
Q

Where is C peptide typically secreted?

A

In urine

11
Q

How many phases of Insulin release are there?

A

Two (it is biphasic)

12
Q

Which phase of insulin secretion is lost first in diabetic individuals?

A

1st

13
Q

What are other modulators of insulin secretion?

A

CCK (stimulates via Gq)
Somatostatin (Inhibits via Gi)
Ach (stimulates via Gq)
GIP (stimulates)

14
Q

T/F: Insulin downregulates its own receptor.

A

True

15
Q

What is an alternative intracellular pathway for glucose uptake INDEPENDENT of insulin.

A

AMP-kinase results in GLUT4 translocation to plasma membrane.

16
Q

What stimulates AMPK mediated (insulin independent) uptake of glucose?

A

Muscle contractions

17
Q

T/F: Exercise increases insulin sensitivity.

A

True

18
Q

Where are incretins derived from?

A

Intestine

19
Q

What are examples of incretin hormones?

A

GLP-1

GIP

20
Q

Actions of incretin hormones?

A

Stimulate Insulin secretion (glucose dependent)
Inhibit glucagon secretion
Slow gastric emptying

21
Q

Incretin is secreted in response to what?

A

GI glucose and fat