Define the following:
(a) Exocrine gland
(b) Endocrine gland
(a) Exocrine gland : Glands which pour their secretions through the ducts eg Liver and Pancreas.
(b) Endocrine gland : Endocrine glands are glands of the endocrine system that secrete their products, hormones, directly into the blood rather than through a duct. They are ductless.
(c)Hormone : Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts.