The layer of cells that covers the outer, and lines the inner, body surfaces is designated as epithelium. In general, many of these cells have a free surface, which is actually or potentially exposed to the external environment (skin, and the respiratory tract), or to a moist environment continuous with the external environment (digestive, reproductive, and urinary tracts). Other epithelial cells, comprising glands found in underlying connective tissue, are in continuity with the surface epithelium by epithelial duct cells. The glandular epithelium secretes diverse products, which are carried to the external surface. The products of these glands include sweat, bile, urine, reproductive cells and associated glandular secretions, mucus, milk, digestive enzymes, hydrochloric acid, and so on. Some epithelial cells have migrated away and have lost contact with the free surface. These cells form distinctive cellular masses, which are termed endocrine glands.

It is important to remember that everything that enters or leaves the body is either modified or synthesized by epithelial cells or has diffused or has been transported through this tissue. The various functions of epithelium include protection, secretion, excretion, digestion, absorption, lubrication, sensory reception, and reproduction.

We offer the following Standard Process® supplements for support of the epithelium and skin.