Brief note on Endocrine gland

These glands are called endocrine glands.

1. Endocrine glands have internal secretion, directly poured into blood stream.

2. These glands are without ducts (ductless glands) and the secretions pass through blood stream directly.

3. The secretions of this type of gland are always harmones.

4. The secretions (hormons) act in a distant target organ or tissue but not local in action.

5. Glands are more complex in structure.

All endocrine glands function independently but are interdependent also. Over activity or under activity of any of them affect all the system. The endocrine glands are profusely supplied with blood vessels and their secretion control and co-ordinate the complex process of metabolism growth, reproduction and maintain homeostasis.

In human beings, the endocrine system consists of endocrine glands, which have been grouped in to four categories.

(A) Pure Endocrine Glands:

These are pituitary, thyroid, parathyroid, Adrenal, thymus, pineal glands.

(B) Exocrine glands containing endocrine tissues are:

(a) A pair of ovaries

(ii) A pair of testiks

(iii) Pancreas (Islet tissue)

(C) The local endocrine tissue is many. Most of them are located in the gastro-intestinal tract.

i) Gastric mucosa

ii) Intestinal mucosa

(D) Temporary Endocrine structures are:

(a) Placenta.

(b) Graflian follicle

(c) Corpus luteum

Besides, a nervous structure called hypothalamus of the brain is integrated with the endocrine system and also secretes hormones.