Hormones: These are the chemical messengers secreted in very small amounts by specialized tissues called ductless glands. They act on target tissues/organs usually away from their source. Endocrine System helps in control and coordination through chemical compounds called hormones.

Endocrine Glands 

They are the chemical messengers that are secreted in small quantities. There are two types of glands-endocrine glands and exocrine glands. Endocrine glands do not have ducts to carry the secretion and they produces the hormones.
Exocrine glands do have ducts to carry their secretion. List of different hormones secreted, and their function are given below-