1,362
edits
Changes
Pancreas - Anatomy & Physiology (view source)
Revision as of 09:40, 18 July 2008
, 09:40, 18 July 2008→Endocrine Function
===Insulin===
===Insulin===
[[Image:Pancreatic Beta Cell.jpg|thumb|right|150px|Pancreatic Beta Cell - Copywright RVC 2008]]
*Insulin is stimulated under conditions of hyperglycaemia and inhibited under conditions of hypoglycaemia.
*It has an ''anabolic'' effect on energy sources.
*It is a small polypeptide consisting of two chains; A and B; which are linked by disulphide bonds.
**It is synthesised inactively as a pre-pro-hormone which undergoes cleavage to produce the active form.
*Insulin is released when blood glucose levels are high. The process of insulin release occurs as follows:
**GLUT 2, which only operate at high glucose concentrations, are present in the plasma membranes of β cells.
**After a meal, glucose concentrations in the blood rise and glucose is taken into the cell.
**Glucose is metabolised inside β cell which produces ATP.
**ATP inhibits potassium channels which depolarises the plasma membrane.
**Depolarisation causes calcium signalling, which stimulates insulin to be released.
==Vasculature==
==Vasculature==