What are hormones? List various characteristics of hormones. Discuss feedback mechanism of hormones.

Hormones:

1. These are the chemical messengers of our body.
2. They are secreted by the endocrine glands and work as control and regulatory mechanism of various processes in our body.
3. They, along with the nervous system, coordinate various organ systems within us.
4. Examples include Insulin, thyroid hormones, corticosteroids, glucagon, etc.

Characteristics of hormones:

1. Hormones are secreted by special glands.
2. They may be proteins, steroids, or amino acids in nature.
3. They are small molecules.
4. They act on tissues away from their source.
5. They reach their target tissues through the bloodstream.
6. Their mode of action is slower than neurons.
7. They control the secretion of other glands as well as regulate different cellular processes.

Feedback mechanism in hormones:

1. There is a peculiar relation between hormones secreted by these endocrine glands.
2. One gland or hormone stimulates the secretion of another hormone.
3. When there is a sufficient amount of this hormone secreted, it suppresses the secretion of its stimulating hormone.
4. This type of dependence is called a feedback mechanism.
5. It is an efficient way of maintaining homeostasis in the body.
6. The pituitary gland secretes the Thyroid-stimulating hormone which stimulates the thyroid to secrete thyroid hormones.
7. When there is enough thyroid hormone, it will, in turn, send signals which tend to stop the secretion of the thyroid stimulating hormone.