The Endocrine System is the collection of glands that produce hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep and mood among other things. The Endocrine System is made up of glands that secrete chemicals called hormones into the blood Stream or surrounding tissues. The word endocrine derives from the Greek words "endo," meaning within, and "crinis," meaning to secrete.
Although the hormones circulate throughout the body, each type of hormone is targeted toward certain organs and tissues. The endocrine system gets some help from organs such as the kidney, liver, heart and gonads, which have secondary endocrine functions. The kidney, for example, secretes hormones such as erythropoietin and renin. Although we rarely think about the endocrine system, it influences almost every cell, organ, and function of our bodies. The endocrine system plays a role in regulating mood, growth and development, tissue function, metabolism, and sexual function and reproductive processes. The endocrine system is in charge of body processes that happen slowly, such as cell growth. Faster processes like breathing and body movement are controlled by the nervous system. But even though the nervous system and endocrine system are separate systems, they often work together to help the body function properly.