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
The main endocrine glands in the body are :
Islets of Langerhans
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
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.