The endocrine system consists of glands that regulate, control, and co-ordinate body functions by secreting hormones into the bloodstream. Endocrine glands are ductless; i.e. they release the hormones directly into the blood.
Proper functioning of the endocrine system ensures cell growth, metabolism, reproductive system development and those body processes that happen over a period of time. The beauty of the endocrine system is that the hormones released carry messages only to relevant cells. Hormones are recognized by their shape and chemical structure.
The major endocrine organs are pituitary gland, thyroid gland, parathyroid, pancreas, gonads, and pineal glands.
The pituitary is known as the “Master Gland” and can be seen below the lower portion of the brain. It secretes the following hormones –
1. Somatotropin – This is a growth hormone and it also stimulates the release of Growth Factor 1 from the liver.
2. Thyrotropin – Necessary for iodine absorption by the thyroid glands.
3. Beta-endorphin – Suppresses pain.
4. Follicle-stimulating hormone- It stimulates maturation of ovaries in females and seminiferous tubules in males.
5. Prolactin – It stimulates release of milk from mammary glands.
It is interesting to note that endorphins produced by the pituitary gland are opiates and actually related to morphine. These hormones are released when we feel pain. Endorphins are also feel-good hormones that help lift our spirits. Apart from the feeling of pain, activities that make us feel good stimulate the release of endorphins. Exercise is known to lead to an endorphin rush.
The pineal gland is located near the central portion of the human brain. It secretes melatonin which acts as an antioxidant and is related to our sleeping rhythms.
The thyroid gland secretes the following hormones –
1. Thyroxine – This stimulates oxygen use by the body and helps regulate the basal metabolic rate.
2. Calcitonin – It plays a role in bone development.
The thyroid glands are important regulators of body metabolism. If these glands go awry, an individual will suffer from either hypothyroidism or hyperthyroidism. It is a well-known fact that iodine deficiency can lead to thyroid malfunctioning; the thyroid enlarges and a condition known as goiter results.
Gonads release sex hormones. Ovaries in females and testes in males serve as hormone-producing gonads. Testes produce testosterone which spurs the growth of muscle, increases strength, and bone density. It is associated with the development of secondary sexual characteristics in males. The ovaries produce progesterone that plays an important role in the female reproductive cycle. It is related to the development of secondary sexual characteristics in females.
The parathyroid gland located close to the thyroid glands produces parathyroid hormone which increases the level of calcium in blood.