Week 8

Question 1

Define polyuria.

Answer 1

Increased urine output

Question 2

What are the hormones produced by the pancreas?

Answer 2

• Insulin
• Glucagon
• Somatostatin
• Pancreatic polypeptide
• Amylin
• Ghrelin

Question 3

What are the cell types that secrete glucagon?

Answer 3

Alpha cells

Question 4

What type of cell secretes insulin and amylin?

Answer 4

Beta cells

Question 5

What regulates glucagon secretion?

Answer 5

Inhibits:

• Ghrelin
• Somatostatin
• Insulin

Question 6

What regulates insulin secretion?

Answer 6

Inhibits:

• Ghrelin
• Somatostatin

Stimulate:
-Glucagon

Question 7

How does insulin circulate in the blood?

Answer 7

Unbound

Question 8

What are the pro hormones of insulin?

Answer 8

• Preproinsulin
• Proinsulin
• Insuin & C-peptide

Question 9

What can measuring the amount of C-peptide tell you?

Answer 9

It can give you a measure of the Beta cell function

Question 10

Describe the mechanism of insulin secretion.

Answer 10

• Glucose is transported into the cell through GLUT 2
• Increased glucose concentration and metabolism in beta cells
• Increased ATP:ADP ratio in the cell
• This causes the ATP-sensitive potassium channels to close
• There is now no movement of K+ which will cause the membrane to depolarise
• The depolarisation will cause the Ca++ channel to open
• This will cause the exocytosis of insulin

Question 11

What are the factors that will increase insulin secretion?

Answer 11

• increased blood glucose
• increased blood free fatty acids
• increased blood amino acids
• GI hormones (CCK, secretin, gastrin)
• glucagon
• beta adrenergic stimulation
• sulfonylurea drugs

Question 12

What are the factors that will decrease insulin secretion?

Answer 12

• decreased blood glucose
• fasting
• somatostatin
• alpha adrenergic activity
• leptin
• K+ depletion

Question 13

What receptor does insulin use?

Answer 13

-tyrosine kinase

Question 14

Describe insulins binding to the receptor?

Answer 14

-it binds with the alpha subunit on the outside of the cell and auto-phosphorylates portions of the beta subunits within the cell

Question 15

Which GLUT transporter is insulin dependent?

Answer 15

GLUT 4

Question 16

What are the immediate effects of insulin?

Answer 16

• increased glucose transport, amino acids and K+ into cells
• stimulates protein synthesis
• inhibits protein degradation
• activates glycogen synthase

Question 17

What are the delayed effects of insulin?

Answer 17

-Increase mRNA’s

Question 18

What is dominant in a fasting state?

Answer 18

-glycogen

Question 19

What hormone work synergistically with insulin?

Answer 19

Growth Hormone

Question 20

What second messenger does glucagon use?

Answer 20

cAMP

Question 21

What are the actions of glucagon?

Answer 21

• Increase glycogenolysis
• increase gluconeogenesis
• increases lipolysis

Question 22

What stimulates glucagon?

Answer 22

• decreased serum glucose
• exercise
• fasting
• some amino acids

Question 23

What inhibits glucagon?

Answer 23

• Fatty acids
• Somatostatin
• Insulin

Question 24

What is glucagon’s mechanism of action?

Answer 24

• activates adenylyl cyclase in the liver
• this forms cAMP
• activates protein kinase regulator protein
• converts into phosphorylase A
• promotes the degradation of glycogen into glucose and release by liver cells

Question 25

What is the action of somatostatin?

Answer 25

- Inhibits insulin, glucagon and pancreatic polypeptide secretion - Decreases gastric motility and secretion

Question 26

What are some of the other hyperglycaemic hormones?

Answer 26

- GH - Cortisol - Thyroid hormones - Epinephrine and norepinephrine

Question 27

What is the cause of diabetes mellitus?

Answer 27

- defect in insulin secretion - defect in insulin action - both of the above

Question 28

What are some of the risk factors for diabetes?

Answer 28

- central obesity - hypertension - low HDL - smoking - family history - inactive lifestyle

Question 29

What is the difference in type 1 and type 2 diabetes mellitus?

Answer 29

Type 1: the beta cell destruction leads to insulin deficiency Type 2: a progressive insulin secretory defect on the background of insulin resistance

Question 30

What is gestational diabetes?

Answer 30

Any degree of glucose intolerance with the onset of first recognition during pregnancy

Question 31

What are some of the symptoms of Type 1 diabetes?

Answer 31

- ketonuria - polyuria - polydipsia - weight loss - young age - family history of autoimmune disease - rapid onset of symptoms

Question 32

Describe what happens to lead to diabetic ketoacidosis?

Answer 32

- increased blood fatty acid and ketoacid concentration from increased lipolysis of fat - this increase in ketoacids can lead to diabetic ketoacidosis (DKA)

Question 33

What can cause insulin resistance?

Answer 33

- obesity - excess cortisol - excess growth hormone - pregnancy - polycystic ovarian syndrome

Question 34

What are the lab test that will confirm a diagnosis of diabetes?

Answer 34

- fasting plasma glucose - oral glucose tolerance test - HbA1c