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Endo/Repro Midterm > Endocrine Pancreas > Flashcards

Endocrine Pancreas Flashcards

1
Q

Endocrine cells of the pancreas secrete what?

What role does it play?

Cells arranged in clusters called ____.

What innervated it?

A

Insulin, glucagon, somatostatin

Regulating lipid, CHO, and AA metabolism

Islets of Langerhans

Adrenergic, cholinergic, peptidergic neurons

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2
Q

Cells of the endocrine pancreas and their secretions

A

Beta cells (central): insulin and C peptide

Alpha cells (peripheral): glucagon

Gamma cells (between alpha and beta cells): somatostatin; send dendrite-like processes to beta cells

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3
Q

How do the cells of the Islets of Langerhans communicate with each other?

A

Gap junctions

Blood supply: islets receive 10% of pancreatic blood flow; venous blood from beta cells carries insulin to alpha and gamma cells (center to periphery)

Paracrine actions work in reverse of blood flow

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4
Q

Insulin is a major ____ hormone.

Secreted in response to _____ ingestion.

____ is its major stimulator factor

A

Anabolic

CHO and/or protein

Glucose

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5
Q

Signal peptide with A and B chains connecting peptide (C peptide); no disulfide bonds

A

Preproinsulin

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6
Q

No signal peptide; C peptide still attached to insulin; packaged into secretory granules; proteases cleave proinsulin***

A

Proinsulin

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7
Q

____ is the marker of endogenous insulin secretion ***

A

C peptide

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8
Q

Describe the step to insulin release

A

Glucose enter cell by GLUT-2 (always on membrane); GLUT-4 (inside cell, on membrane when needed)

Glucose is phosphorylated by glucokinase

Glucose-6-phosphate is oxidized promoting ATP generation

ATP closes the INWARD RECTIFYING K channel (increase membrane potential, becoming more positive)

Plasma membrane is depolarized

Activation of VOLTAGE-GATED Ca channels; Ca enters

Initiates mobilization of insulin containing vesicles to plasma membrane and exocytosis

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9
Q

Rise in ATP ____ K channels

____ receptor is associated with ATP-dependent K channels; increase insulin secretion (membrane depolarization, Ca enter, treatment of type 2 DM)

____ secretion measures function of beta cells and endogenous insulin secretion

A

Closes

Sulfonylurea

C peptide

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10
Q

Insulin release is ____.

First phase insulin secretion is ____ first in diabetic pt

Secondary responses ____. ***

A

Biphasic

Lost

Increase

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11
Q

GI peptides, CCK, gastrin, glucagon, phospholipase C, ACh (parasympathetics) ____ insulin secretion.

Somatostatin ____ insulin secretion.

Act independent of ____.

A

Stimulate

Inhibit

Glucose

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12
Q

Insulin binds to a ____ receptor

This receptor autophosphorylates itself and ____.

Insulin-receptor complex is ____ by target cell.

Down Regulation of receptor by ____.

A

Insulin

Other proteins

Internalized

Insulin

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13
Q

Glucose enters cell through GLUT4

A

???? **

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14
Q

Activation of AMP-kinase (AMPK) results in GLUT4 translocation to plasma membrane allowing ____ uptake…acts ____ of insulin.

Stimulated by ____.

A

Glucose

Independent

Muscle contractions

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15
Q

Insulin actions on skeletal muscle

A

Increase glucose uptake (GLUT4)

Increase glycogen synthesis (hexokinase, glucokinase, glycogen synthase)

Increase glycolysis and CHO oxidation (hexokinase, PFK, PDH)

Increased protein synthesis

Decrease protein breakdown

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16
Q

Insulin actions on liver (“put on the break”)

A

Promotes glycogen synthesis (glucokinase, glycogen synthase)

Increases glycolysis and CHO oxidation (glucokinase, PFK, pyruvate kinase)

Decreases gluconeogenesis (PEPCK, fructose-1,6-bisphosphatase, G6P phosphatase)

Increase hexose monophosphate shunt

Increases pyruvate oxidation

Increase lipid storage and decreases lipid oxidation (increase malonyl CoA)

Increases protein synthesis, decrease protein breakdown

17
Q

Insulin actions on adipose tissue

A

Increase glucose uptake (GLUT4)

Increased glycolysis

Decreased lipolysis (inhibits HSL)

Promotes uptake of fatty acids (LPL)

18
Q

Factors that stimulate insulin secretion

A 
Increased blood glucose
Increased blood AA
Increased blood FA and keto acids
Glucagon
Cortisol
Glucose-dependent insulinotropic peptide (GIP)
Vagal stimulation (through ACh)
Potassium
Sulfonylurea drugs
Obesity
19
Q

Factors that inhibit insulin secretion

A 
Decreased blood glucose
Fasting
Exercise
Somatostatin
Alpha-adrenergic agonists
Diazoxide (K channel activator)
20
Q

Coordinated actions of insulin (8)

A

Increased glucose uptake into cells (decrease blood glucose)
Increased glycogen formation
Decreased glycogenolysis
Decreased gluconeogenesis
Increased protein synthesis (decrease blood AA)
Increased fat deposition (decrease blood FA)
Decrease lipolysis (decrease blood keto acids)
Increased K uptake into cells (decreased blood K)

21
Q

BMI

A

Body mass index

Weight (kg)/height (m2)

18.5-24.9 normal
25.0-29.9 overweight
30-39.9 obese
>40

22
Q

This is a fasting blood profile of a pt with type 1 DM

This is a fasting blood profile of a pt with type 2 DM

A

Increase glucose
Decrease insulin
Decrease C peptide
Increase HbA1c

Increase glucose
Increase insulin
Increase C peptide
Increase HbA1c

23
Q

Type 1 DM:

____ insulin secretion.

Destruction of ____ cells.

___ blood glucose, FA, ketoacids, AA

Decreased utilization of ketoacids result in ____.

A

Inadequate

Beta

Increased

Diabetic ketoacidosis (DKA)

Hyperkalemia, osmotic diuresis, glucosuria

24
Q

Hyperkalemia is a shift of ____ out of cells.

A

K *****

25
Q

Treatment of type 1 DM has drawbacks

A

Painful

Lag between glucose measurement and insulin dosing

Delayed absorption of insulin following injections

Poor blood glucose control leads to hyperglycemia

26
Q

Treatment for type 1 DM

A

Beta cell mimetic designer cells (HEK-beta) show glucose-induced insulin release performance comparable to beta cell lines and human islets

27
Q

Type 2 DM:

Insulin resistance

Progressive exhaustion of active ____ cells due to ____ factors.

A

Beta

Environmental

28
Q

Progression of insulin resistance in type 2 DM:

Reactive hyperinsulinemia followed by _____.

Obesity induced insulin resistance includes what?

A

Hypoinsulinemia

Decreased GLUT4 uptake of glucose in response to insulin

Decreased ability of insulin to repress hepatic glucose production

Inability of insulin to repress adipose tissue uptake

29
Q

Insulin resistance of type 2 DM:

Post-receptor signaling results in ____ glucose transporter number and mobilization

A

Decreased

30
Q

Treatment of type 2 DM **

A

Caloric restrictions, exercise

Sulfonylurea drugs

Incretin analog of GLP-1

Slow absorption of CHO

Metformin

31
Q

When you eat a meal a with glucose (oral glucose) you will get ____ insulin response

A

Higher

32
Q

Incretin used to treat ____.

Stimulates ____ secretion.

Inhibits ____ secretion.

A

Type 2 DM

Insulin

Glucagon

33
Q

Glucagon is stored in granules of ____ cells.

Stimulated by a ____ in blood glucose.

Stimulated by ____ in AA, fasting, CCK, beta-adrenergic agonists, ACh

What inhibits glucagon?

A

Alpha

Decrease

Increase

Insulin, somatostatin, FA, ketoacids

34
Q

Actions of glucagon on liver

Other actions

A

Increases blood glucose
Increases gluconeogenesis
Increases glucogenolysis
Inhibits glycogen synthesis

Lipolysis of adipose tissue and skeletal m (increases FA)

Ketoacids produced form FA

Endo/Repro Midterm (11 decks)

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