Pancreas

Question 1

What inhibits insulin secretion?

Answer 1

Adrenaline and somatostatin (pancreatic delta cells).

Question 2

What 2 tissues do insulin act on, and what do they do here?

Answer 2

Liver —> inhibit glycogenolysis (glycogen to glucose), gluconeogenesis (non carbohydrate sources to glucose) and will stimulate glycogen synthesis.
Muscle —> increases facilitated transport of glucose via glut-4 transporters, stimulates glycogen synthesis.

Question 3

What is the step by step process insulin achieves its mechanism of action?

Answer 3

Insulin binds to insulin surface receptors and results in the activation of a tyrosine kinase enzyme.
This results in a phosphorylation cascade resulting in GLUT-4 transporters moving to the surface of the cell (muscle, liver, fat) membrane. Glucose influx.

Question 4

What is an incretin?

Answer 4

A peptide released from the digestive tract in response to food. Will stimulate increased insulin release from pancreatic beta cells.

Question 5

What is diabetic ketoacidosis?

Which type of diabetes?

Answer 5

Ketoacidosis —> type 1.
The greater action of glucagon means that there is a decrease in BGL. This results in other fuel sources being mobilised increasing lipolysis and fatty acid metabolism. This causes ketone body release increasing acidity. Response is increasing ventilation, will dehydrate and risk stupor/coma.

Question 6

What is hyperosmolar coma?

Which type of diabetes?

Answer 6

Hyperosmolar coma —> type 2.
Hyperglycaemia causes increased diuresis and subsequent dehydration leading to stupor/coma.
There is enough insulin present to prevent ketoacidosis however.

Question 7

What are 5 ways of managing diabetes?

Answer 7

Diet —> increase fibre and decrease sugar.
Alcohol —> prevents glycogenesis.
Exercise —> enhances glycaemic control.
Smoking —> will raise BGL.
Glycosylated haemoglobin —> BGL measure.

Question 8

What are the 5 hypoglycaemic agents?

Answer 8

Biguanides, sulfonylureas, glitazones, incretin enhancers, alpha-glucosidase inhibitor

Question 9

What are the mechanisms of action of the 5 oral hypoglycaemic agents?

Answer 9

Biguanides —> increase insulin sensitivity, increasing insulin uptake into skeletal muscle cells.
Sulfonylureas —> depolarise beta pancreatic cells to increase insulin release.
Glitazones —> increase peripheral sensitivity to glucose and alter gene expression of glucose metabolisers.
Incretin enhancers —> self explanatory.
a-glucosidase inhibitor —> delay glucose absorption and distribution.