Pancreas

The pancreas and endocrine function

The main component of the pancreas, which we need to be aware of, is the B-cell, which is the main endocrine cell component of the islets of Langerhans. B-cells produce insulin and A-cells produce glucagon (D-cells produce somatostatin. The B-cell is designed to synthesize insulin and has a mechanism to regulate the rate of secretion of insulin in response to glucose. Proinsulin is the biosynthesizer of insulin and permits the correct orientation of the interchain disulphide bridges in the insulin structure so that the two polypeptide chains are formed correctly. The proinsulin molecule is then split in the Golgi complex to form insulin. Granular insulin is transported through the cell membrane by exocytosis.

Explanation of the animation.

Fasting

In the fasting state, when blood glucose lowers, there is a concomittant physiological response in each of the major organs involved in glucose regulation.

Pancreas: Alpha cells produce glycogen which is released into the blood stream.

Muscle: The breakdown of glycogen reserves releases energy for muscle action, which releases the by-products of ketones into the bloodstream.

Adipose Tissue: Fat stores are broken down to release energy and acids.

Liver: The fatty acids and ketones initiate glycogen breakdown for energy and by the conversion into glucose.

Brain: The direct cell transfer and usage of glucose by the brain without ennzyme action provides a direct correlation between functionality and glucose levels. Therefore falling glucose levels will result in the symptoms associated with hypoglycaemia.

Feasting

In the feasting state, when blood glucose levels rise, there is a concomittant physiological response in each of the major organs involved in glucose regulation.

Pancreas: Beta cells produce insulin which is released into the blood stream for cell initiation.

Muscle: Insulin action triggers the release of glucose for energy to intiate muscle action.

Adipose Tissue: Glucose is released for energy and acids.

Liver: Glucose is converted for storage as glycogen.

Brain: The direct cell transfer and usage of glucose by the brain without ennzyme action provides a direct correlation between functionality and glucose levels. Therefore falling glucose levels will result in the symptoms associated with hypoglycaemia and rising will result in the symptoms of ketoacidosis.