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| [[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]] | | [[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 secretion 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. |
| *It is a small polypeptide consisting of two chains; A and B; which are linked by disulphide bonds. | | *It is a small polypeptide consisting of two chains; A and B; which are linked by disulphide bonds. |
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| **GLUT 2, which only operate at high glucose concentrations, are present in the plasma membranes of β cells. | | **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. | | **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. | + | **Glucose is metabolised inside the β cell which produces ATP. |
| **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. |
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| *Increased glucose levels inside the cell increases the rate of glyogenesis and an increase in the rate of production of triacylglycerides. | | *Increased glucose levels inside the cell increases the rate of glyogenesis and an increase in the rate of production of triacylglycerides. |
| *There is an increase in basal metabolic rate in other tissues. | | *There is an increase in basal metabolic rate in other tissues. |
− | *Insulin regulates the | + | **Insulin regulates the reaction in glycolysis where PEP is converted into pyruvate. This reaction is regulated by the enzyme pyruvate kinase. Insulin '''activates''' this enzyme by ''dephosphorylation'' via protein phosphatase 1 (PP1). This increases metabolism. |
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| ==Vasculature== | | ==Vasculature== |