Hormone, a natural substance secreted by plants and animals that functions in the direction of physiological activities and in maintaining homeostasis. Hormones carry out their activities by evoking responses from particular organs or tissues that are acclimated to react to little quantities of them. The conventional view of hormones is that they are sent to their targets in the bloodstream following discharge from the glands that secrete them. This kind of flow (directly into the bloodstream) is called endocrine secretion. The description of the term hormone has been extended beyond the primary description of a blood-borne secretion, but, to add similar regulatory substances that are divided by diffusion across cell membranes rather than a blood system. Hormones may affect many different processes of the human body like:- ●Growth and development  ●Metabolism - how your body gets energy from the foods you eat ●Sexual function  ●Reproduction  ●Mood ...