Pancreas

Question 1

What is somatostatin?

Answer 1

A peptide hormone released by the pancreas to regulate islet cell secretion.

Question 2

Does the brain have stores of glucose?

Answer 2

No

Question 3

What is the renal threshold for glucose?

Answer 3

10mmol/L

Question 4

When and how does the renal threshold for glucose change?

Answer 4

during pregnancy it is lowered

in the elderly it is raised

Question 5

What is the sequence of insulin synthesis?

Answer 5

mRNA translated to form preproinsulin
enters ER and signal removed to form proinsulin
transport to Golgi
exposed to specific endopeptidases which cut off C peptide
packaged into secretory vesicles

Question 6

What is the process of insulin secretion?

Answer 6

increased extracellular glucose
glucose transported into beta cells (GLUT2)
K+ channels close
membrane depolarisation
influx of calcium ions
triggers exocytosis

Question 7

How do insulin receptors work?

Answer 7

alpha chains move to fold around the insulin
beta chains move and activates tyrosine kinase
initiates a phosphorylation cascade resulting in an increase in GLUT4 expression

Question 8

What are the features of glucagon structure?

Answer 8

29 amino acids
1 polypeptide chain
no disulfide bridges
flexible

Question 9

What is diabetes insipidus?

Answer 9

The kidneys are unable to conserve water. Will also cause hyperglycaemia.

Question 10

Where is the pancreas?

Answer 10

nestled in the C curvature of the duodenum