Gland

A gland is an organ in the body which synthesizes substances. Sort of like a tiny production plant, it creates anything from milk to adrenaline and all things in between. Substances are then released by the gland into the bloodstream, or sometimes through ducts to the exterior of the body, or to other places depending on the type of gland it is. The two basic types of glands are endocrine and exocrine. Endocrine glands secrete their substance directly onto a surface whereas exocrine glands secrete their substance via a duct. There are various sub-types of gland within the two types.