Glands Glands of the body are classified as either exocrine or endocrine types.
Exocrine glands are glands that retain ducts to body surfaces.
Endocrine and exocrine glands secrete various products. These include hormones, enzymes, metabolites, and other molecules. In exocrine glands, products of these cells collect in the duct of the gland and flow toward the surface to which the duct is in contact. Since endocrine glands lack ducts, the product is released across the cell membrane into interstitial spaces around the cells. Diffusion of the product into capillaries follows.