1. Endocrine System – Two hormones are produced by the posterior lobe of pituitary gland. One hormone helps to conserve water in the body according to requirement, and the other has no effect on males but has certain effect in females.
2. Thyroid gland
The thyroid gland is located in the neck and fits closely around the from and side of trachea (wind pipe) just below the organ of voice of larynx. The thyroid receives a lot of blood supply to nourish its cells and to carry away the hormones it produces. It produces two hormones.
1. Thyroxin 2. Calcitonin
The above hormones of thyroid are produced under the influence of TSH from the pituitary gland. The thyroid hormones increase the consumption of oxygen by the body tissues. This increases the rate of metabolism. They also increase the ability of a person the think. Adequate supply of these hormones is also needed for normal growth and skeletal development in children.
Goiter (abnormal enlargement of thyroid) is due to its malfunction. The major cause of this disease is iodine deficiency is iodine deficiency in the food / body.
3. Parathyroid gland
These are very small structures usually four in number embedded in the back side of the thyroid gland. They produce parathyroid hormones which control the amount of calcium and phosphate in the blood serum.
4. Pancreas
Pancreas is present in the abdominal cavity close to the stomach. Pancreas is known as double gland as it has two kinds of glandular tissues. One exocrine and the other endocrine in function. The main bulk of pancreas is exocrine that produces pancreatic juice which helps in the digestion and is carried by the pancreatic duct to the intestine. Distributed at various places in its tissue are groups of cells, known as islets of Langerhans which are endocrine (not having ducts). The islets of Langerhans produce two hormones:
1. Insulin 2. Glucagon
These two hormones have opposite effect in regulating use of glucose in the body. The two hormones therefore counter balance each other. When the amount of glucose in the blood plasma increases the production of insulin is also increased due to which the entry of glucose into muscles and other tissue from blood is made easier. In the absence of insulin the glucose level in the blood is raised resulting in the disease known as diabetes mellitus. (Diabetes =to go through; mellitus = honey)
Another form of diabetes is diabetes insipidness in which there is excessive flow of urine.
Too much insulin in the blood may cause lowering of glucose level to such an extent that it may result in unconsciousness and death. Glucagon, the second hormone in such emergency situations brings about release of stored blood sugar so as to maintain a proper level of glucose in the blood.
5. Adrenal glands
Adrenal glands are paired and lie in abdominal cavity above the kidneys. Adrenal glands produce adrenaline which prepares the body for action in an emergency by raising blood pressure, increasing heart and breathing rate.
6. Gonads
They have two functions, to produce male sex-cells (sperms) and to produce the male hormones androgens e.g. testosterone. These are produced by the interstitial cells of testes. Testosterone helps in the development of male secondary sex characters such as growth of hair on the face and thickness or coarseness of voice in males.