Answer:
Pancreas- It mainly function as an endocrine gland, secreting a number of digestive enzymes. Along with that it has a very unique function of secretion of hormones which mainly regulate the blood sugar level. The hormones are secreted by the pancreatic islets also known as islet of Langerhans.
These hormones secreted are glucagon, insulin, somatostatin, and pancreatic polypeptide (PP). Mainly the secretion of glucagon and insulin is done for balancing the level of glucose in blood.
Explanation:
The beta cell produces the hormone insulin, as each islet is comprised of 75 percent of beta cells.
Elevated blood glucose levels stimulate the release of insulin. Now, the function of insulin is to balance the blood sugar level.
<u>Secretion of Insulin Step by step:</u>
- It all starts from the presence of food in the intestine which initiates the release of gastrointestinal tract hormones such as glucose-dependent insulinotropic peptide.
- This is in turn the initial trigger for insulin production and secretion by the beta cells of the pancreas.
- Once nutrient absorption occurs, the resulting surge in blood glucose levels further stimulates insulin secretion.
- insulin appears to activate a tyrosine kinase receptor, triggering the phosphorylation of many substrates within the cell.
- These multiple biochemical reactions converge to support the movement of intracellular vesicles containing facilitative glucose transporters to the cell membrane.
- Insulin triggers the rapid movement of a pool of glucose transporter vesicles to the cell membrane, where they fuse and expose the glucose transporters to the extracellular fluid.
- The transporters then move glucose by facilitated diffusion into the cell interior.
Note:However, the red blood cells, as well as cells of the brain, liver, kidneys, and the lining of the small intestine, do not have insulin receptors on their cell membranes and do not require insulin for glucose uptake.
