Glandular System

Glands are very important parts of our body. They are made up of special types of secretive cells. They are of two types:

1. Exocrine glands

2. Endocrine glands

Exocrine glands:

Exocrine glands bear special ducts through which they pass their secretions to the site of action. The secretion of exocrine glands is called enzymes. Salivary glands, tear glands and mucous glands are some examples of exocrine glands.

Endocrine glands:

Endocrine glands are ductless glands. They directly pour their secretions into the bloodstream and the blood carries their secretions to the site of action.The secretions are called hormones. The major endocrine glands of our body are as follows:

1. Pineal gland
2. Pituitary gland
3. Thyroid gland
4. Parathyroid gland
5. Adrenal gland
6. Gonads

Functions of a pituitary gland, thyroid gland, parathyroid gland, adrenal gland, and gonads.

1. Pineal gland:

2. Pituitary gland:

It lies below the cerebrum. It is a pea-sized organ which secretes the hormone. This gland controls the other gland. It is also called master gland of our body because it influences all other endocrine glands by releasing stimulating hormones.

3. Thyroid gland:

This gland lies at the both sides of the windpipe in the neck. The thyroid gland secretes thyroxin. Thyroxin which regulates the iodine required for physical and mental growth. In the deficiency of iodine, the gland swells up to form goiter.

4. Parathyroid gland:

There are four parathyroid glands behind the thyroid gland. These secretes parathormone which regulates the calcium and phosphorus in our body. Deficiency of this hormone weakens the muscles. Excess of this hormone weakens the bones by absorbing the calcium. The absorbed calcium in the blood may form stones in the kidneys.

5. Thymus gland:

This gland gets being large till the adolescence and continues to get small with an increase in age. It is located in front of the heart and behind the sternum. It weighs 10 gram at a young age, 30-40 gram at teenage and around 15 gram at an old age. It produces thymosin that helps in producing lymphocytes. Lymphocytes produce antibody.

6. Pancreas:

The pancreas is a glandular organ in the digestive system. It is located in the abdominal cavity behind the stomach. It is an endocrine gland producing insulin, glucagon which circulate in the blood and regulates an amount of glucose (sugar) in the blood. The pancreas is also a digestive organ, secreting pancreatic juice containing digestive enzymes that assist digestion and absorption of nutrients in the small intestine.

7. Adrenal gland:

There is a pair of adrenal glands located just above the each kidney. They produce adrenaline hormone which helps in carbohydrate metabolism and regulation of glucose in the blood. Deficiency of this hormone causes weakness, vomiting, low blood pressure, decrease in sugar level, etc.

8. Gonads :

Gonads are different in male and female. Female have ovaries and male have testes. The hormones that they produce are also different in male and female. Ovaries produce two types of hormones called estrogen and progesterone. Testes produce testosterone and androgen hormones.

1. Ovaries: Ovaries are the female gonads. Ovaries help a female in the growth and development of the body including maturation before and after puberty, growth and development of the reproductive organs including the growth in the size of sex organ, breast and vagina, during pregnancy. It also helps in the production of milk during breastfeeding of a child.
2. Testes: Testes are the male gonads. Testes help in the growth of testicles and muscles in terms of size and in the development of hoarse voice, nightfall and in the production of sperms and semen. A person without testis becomes a eunuch. He will be unable to reproduce.