Define the following :
(a) Exocrine gland (b) Endocrine gland (c ) Hormone.

Explanation

(a) Exocrine glands are the glands which discharge their secretions via ducts onto the body surface or into the cavities in the body.
(b) Endocrine glands are the ductless glands. These pass their secretions into the surrounding blood for transport to the site of action.
( c) Hormones are the informational molecules (chemical mesengers) sectreted by the endocrine glands in one part of the body in response to changes in external or internal environment, and carried by blood to another part where they stimulate or inhibit specific physiological processes.