A gland's an organ in an animal's body that synthesizes a substance for release such as hormones or breast milk, often into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Types Glands can be divided into 2 groups: Endocrine glands — are glands that secrete their product directly onto a surface rather than through a duct. Exocrine glands — secrete their products via a duct, the glands in this group can be divided into thr… (More on Gland)