[ Endocrine System ]
A collection of [ Gland ] An organ that synthesises and secretes substances. Organs that secrete substances (such as hormones) into the blood are endocrine glands. Those that secrete substances outside the blood (such as milk or sweat) are exocrine glands. More and organs that secrete [ hormone ] A substance that acts as a signal between organs and tissue to regulate physiology and behaviour. Hormones are secreted directly into the circulatory system by specialised cells in glands and other organs. They regulate metabolic activities, growth More into the circulatory system. Those hormones act as regulatory signals.