Islets of Langerhans in the Pancreas

Endocrines : The glands of the body may be divided into those with an external secretion (exocrine glands) and those with an internal secretion (endocrine glands). Example of exocrine glands are the sweat, Lachrymal and mammary glands which pass their secretion along the ducts to the external surface of the body and the glands of the mouth, stomach, and intestine which pass their secretions along ducts into the alimentary tract. The endocrine or ductless gland on the other hand have no ducts or openings to the exterior.

The secretions are passed directly into the blood stream and transmitted to the tissues.

A hormone is a chemical substance produced by the endocrine glands and their overall function is to regulate the activities of various body organs and their functions. The first hormone was discovered by Bayliss in 1903.

The main endocrine glands in the body are :

Thyroid

Parathyroid

Islets of Langerhans

Adrenal gland

Pituitary and

Sex glands

ISLETS OF LANGERHANS IN THE PANCREAS

The Pancreas is both an exocrine gland secreting digestive juice through a duct into the duodenum and an endocrine gland secreting hormone into the blood stream. It consists of head, body and tail. The head fits into the curve of duodenum The body and tail are directed towards the left. The pancreatic islets represents the endocrine part of the pancreas. Most of the islets are located in the tail and only a small number in the head of the pancreas. There are two different types of cells in the islets of langerhans. The alpha cells and beta cells are very important. The alpha cells secrete a hormone Glucagon whereas the beta cells secrete insulin.

Functions of Glucagon

Increases the blood glucose level

Breaks down the liver glycogen into glucose.

Stimulates the break down of lipid in adipose tissue.

Functions of Insulin

Converts glucose into glycogen and accelerates the transport of glucose from the blood into the cells.

Decreases the blood sugar level.

Builds up the glycogen store in the liver.

Deficiency of Insulin

Hyposecretion of insulin results in Diabetes mellitus. It is caused due to elevated blood sugar level. This condition is known as hyperglycemia. This condition leads to the condition 'glycosuria' in which sugar is excreted in the urine. Carbohydrates as well as protein and fat metabolism are affected in the diabetics.

Symptoms of diabetes are:

Excessive thirst, hunger and urination

Loss of weight.

Weakness, restlessness and fatigue.

Decreased resistance to infection.

Itching of the genitals.

Diabetes can be kept under check by taking a high protein and low carbohydrate diet. If Diabetes cannot be controlled by diet alone, insulin must be administered by injection.