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Pancreas - Anatomy & Physiology (view source)
Revision as of 10:00, 18 July 2008
, 10:00, 18 July 2008→Insulin
===Insulin===
===Insulin===
[[Image:Pancreatic Beta Cell.jpg|thumb|right|150px|Pancreatic Beta Cell - Copywright RVC 2008]]
[[Image:Pancreatic Beta Cell.jpg|thumb|right|150px|Pancreatic Beta Cell - Copywright RVC 2008]]
[[Image:Insulin Secretion Pattern.jpg|thumb|right|150px|Insulin Secretion Pattern - Copywright RVC 2008]]
*Insulin is stimulated under conditions of hyperglycaemia and inhibited under conditions of hypoglycaemia.
*Insulin is stimulated under conditions of hyperglycaemia and inhibited under conditions of hypoglycaemia.
*It has an ''anabolic'' effect on energy sources.
*It has an ''anabolic'' effect on energy sources.
**ATP inhibits potassium channels which depolarises the plasma membrane.
**ATP inhibits potassium channels which depolarises the plasma membrane.
**Depolarisation causes calcium signalling, which stimulates insulin to be released.
**Depolarisation causes calcium signalling, which stimulates insulin to be released.
*Pre-formed granules of insulin are release initially, but this supply soon diminishes. This produces a decrease in plasma insulin levels. Insulin levels are restored as de novo insulin is synthesised and secreted.
*Insulin exerts it's anabolic effect on adipocytes and skeletal muscle.
**It binds to receptors on the cell membrane, which triggers an intracellular signalling cascade.
**This causes preformed granules containing GLUT 4 receptors to be transported and expressed at the cell membrane.
**Cells can now take up glucose from the blood and store it as glycogen or fat.
==Vasculature==
==Vasculature==