The endocrine system is an integrated system of small organs that involve the release of extracellular signaling molecules known as hormones. It is the second communication system within the body, the first is the nervous system. The endocrine system is instrumental in regulating metabolism, growth, development and puberty, tissue function, and also plays a part in determining mood. The field of medicine that deals with disorders of endocrine glands is endocrinology, a branch of the wider field of internal medicine.
The main difference between the endocrine system and the nervous system is speed. Nervous system acts in miliseconds and endocrine acts in seconds to minutes. But endocrine messages last longer.