Together with the nervous system, the endocrine system, also sometimes referred to as the hormone system, constitutes the primary system overseeing the system’s vital functions. The endocrine system regulates metabolic and cellular activity. It makes contact with the body’s cells via hormones. Hormones are chemical substances which act as carriers of information. Communication by means of using chemical substances is the oldest evolutional method of passing information between cells. Each of the hormones has a separate function and the effects of their action may appear within a few seconds or more slowly, over the course of days, months and even years. The endocrine system transmits hormones via the blood, which constitutes an information channel of its own kind.
The endocrine system is made up of numerous organs with the primary task of secreting hormones. The prefix ‘endo-’ comes from the Greek endon, ‘within’, and these organs are known as endocrine glands or ductless glands.
Discoveries of new hormones secreted by organs apparently unconnected with the endocrine system continue to be made. One of those organs is the heart, which, inter alia, produces oxytocin, referred to colloquially as the ‘love hormone’.
Every hormone performs a separate function. Hormonal activity is particularly vital during times of changes in the body’s functions, such as the period of children’s growth and during pregnancy.