3. Endocrine Pancreas

Question 1

What do the endocrine cells of the pancreas secrete

Answer 1

Insulin
Glucagon
Somatostatin

Question 2

How are the endocrine cells of the pancreas arranged

Answer 2

Clusters called Islets of Langerhans

Question 3

In the Islets of Langerhans where are alpha and beta cells located and what do they secrete

Answer 3

Beta cells- centrally located and secrete Insulin and C peptide
Alpha cells- peripherally located and secrete glucagon

Question 4

What are the functions of d and f endocrine pancreas cells

Answer 4

d- secrete somatostatin

F- act like a satiety signal

Question 5

How is blood supplied to islets of langerhans

Answer 5

• Islets receive 10% of pancreatic blood flow
• blood flows first to center (for insulin) and then to periphery
• Paracrine actions work in reverse of blood flow

Question 6

What is the major stimulatory factor of insulin secretion

Answer 6

Glucose

Question 7

What is used as an endogenous insulin secretion marker

Answer 7

C peptide

-Insulin and cleaved C peptide are packaged together in secretory vesicles

Question 8

How does Glucose get into the cell in order for insulin to be released

Answer 8

Glut-2

Question 9

What is the target for treatment of Type 2 DM

Answer 9

Sulfonylurea receptors associated with ATP-dependent K+ channels

Question 10

Insulin release is biphasic, how does that relate to patients with DM

Answer 10

Diabetic individuals lose first phase in insulin secretion

Question 11

What does AMP-kinase (AMPK) have to do with uptake of glucose

Answer 11

Activation of AMPK results in GLUT4 translocation to plasma membrane

(muscle contractions stimulate this process)

Question 12

What stimulates insulin secretion

Answer 12

• Increased glucose concentration
• Increased amino acid concentration
• Glucagon
• Cortisol
• Potassium
• Obesity

Question 13

What inhibits insulin secretion

Answer 13

• Decreased blood glucose
• Fasting
• Exercise
• Somatostatin
• Norepinephrine

Question 14

What does insulin do to skeletal muscle

Answer 14

• Increase glucose uptake
• Increase glycogen synthesis
• Increase glycolysis and CHO oxidation
• Increase protein synthesis
• Decrease protein breakdown

Question 15

What does insulin do to the liver

Answer 15

• Promotes glycogen synthesis
• Increases glycolysis and CHO oxidation
• Decreases gluconeogenesis
• Increase in hexose monophosphate shunt and pyruvate oxidation

Question 16

What does insulin do the adipose tissue

Answer 16

• Increase glucose uptake
• Increase glycolysis
• Decrease lipolysis
• Promote uptake of fatty acids

Question 17

How is glucagon synthesized and where is it stored

Answer 17

• Made as preproglucagon

- stored in dense granules of alpha cells

Question 18

What is the major stimulant for secretion of glucagon

Answer 18

Decreased blood glucose

Question 19

What are the major actions of glucagon on the liver

Answer 19

• Increase blood glucose
• Increase gluconeogenesis
• Increase glucogenolysis
• Inhibit glycogen synthesis

Question 20

Describe Type 1 DM (juvenile onset diabetes)

Answer 20

Inadequate Insulin Secretion

• Destruction of B cells
• Decreased utilization of ketoacids results in DKA
• Hyperkalemia (shift of K+ out of cells)(plasma levels may be normal)
• Osmotic Diuresis / Glucosuria

Question 21

What is Insulin Resistance

Answer 21

Progessive exhaustion of active B-cells

sedentary lifestyle, malnutrition or obesity

Question 22

What is Reactive Hyperinsulinemia

Answer 22

• 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 and lipolysis

Question 23

What is the incretin effect

Answer 23

Type 2 diabetics have a reduced incretin effect