Question

What is the classification of hormones based on the proximity of the site of synthesis to the site of action?

Answer 1

Hormones:

1. Hormones are a type of chemical produced by the endocrine glands.
2. They are transported to the target cells with the help of the circulatory system.

Classification of hormones:

Hormones are classified into three types on the basis of their proximity of the site of synthesis to the site of action that is, paracrine hormones, autocrine hormones, and endocrine hormones.

1. Paracrine hormones: These are the hormones that are produced in proximity to their site of action. Estrogen is a type of paracrine hormone.
2. Autocrine hormones: These hormones act on the same cells which synthesize them. Cytokine interlukin-1 is an autocrine hormone.
3. Endocrine hormones: These hormones are synthesized by endocrine glands and passed in the blood to the target cells containing the suitable receptors. Aldosterone is an example of an endocrine hormone.