This term comes from the English "hormone" and this from the Greek "ὁρμῶν" present participle of "ὁρμᾶν" which means "excite" or "produce movement", hence also the word hormonal and pheromone. The hormone or in the plural, hormones are substances secreted by specialized cells, which are found in internal secretion glands or endocrine glands, also by epithelial and interstitial cells whose purpose is to affect the function of other cells. In other words, hormones are the product of a segregation of some glands in the body of animals, plants and people, transported by blood or by sap and regulate the activity of other organs. There are animal hormones and plant hormones such as auxins, cytokinin, abscisic acid, gibberellin, and ethylene.
As mentioned before, these hormones are found in glands of internal or endocrine secretion, in epithelial and interstitial cells, which are secreted by specialized cells and every multicellular organism produces hormones, and the most studied are those produced by the endocrine glands.
There are natural and synthetic hormones, both can be used frequently when treating certain disorders, especially when it is necessary to compensate for their lack or to increase their levels that are lower than normal values. It is important to note that hormones belong to the group of so-called chemical messengers, where neurotransmitters also belong.
Chemically speaking, hormones in humans can be classified as protein, such as oxytocin or insulin; steroids such as androgens and hormones of the adrenal cortex and feolic hormones such as adrenaline or thyroxine.
