Endocrine Glands

The various endocrine glands in humans are hypothalamus, pituitary gland, thyroid gland, parathyroid glands, pancreas, adrenal glands, ovary (in female) and testis (in males).

• Pituitary gland is also known as 'Master gland' of the body. It is because of the fact that the pituitary gland controls the functioning of most of the endocrine glands.

• Hypothalamus plays an important role in the release of many hormones. For example, when the level of growth hormone is low, the hypothalamus releases growth hormone releasing factor which stimulates the pituitary gland to release growth hormone.

• The gonads i.e., testes and ovary are both endocrine and non-endocrine in function. Their non endocrine function is to produce male and female reproductive cells i.e. sperm and ova respectively.

1.0Endocrine Glands and Their Hormones and Functions

In animals, chemical coordination is achieved through the agency of hormones which function as chemical messengers or informational molecules. Hormones are secreted in very small amounts by specialized tissues in the body called endocrine glands. These glands are ductless and pour their secretions directly into the blood. Blood transports them to the target tissues/organs. Hormones coordinate the activities of living organisms and also their growth. For example, the pancreas secretes two hormones-insulin and glucagon.

2.0Feedback Mechanism

Feedback mechanism is a regulatory mechanism in which presence of certain level of substance promotes or inhibits its further formation. Hormone regulation is mostly done by feedback mechanism. A good example of negative feedback is the release of the hormone insulin. Insulin is a hormone produced by the pancreas. Insulin is released when the amount of glucose in the blood goes up. It stimulates the target cells to take glucose out of the blood which is utilized in cells during respiration or is stored as glycogen. When cells take up glucose from the blood this makes the glucose level reach to normal state.  With the fall in blood glucose level, insulin secretion decreases. This checks the further fall in blood glucose level. So, the negative feedback work to keep the blood glucose level normal.

3.0Also Read