The term "epithelium" refers to layers of cells that line hollow organs and glands. It is also those cells that make up the outer surface of the body.
Epithelial cells help to protect or enclose organs. Most produce mucus or other secretions.
Certain types of epithelial cells have tiny hairs called cilia, which help remove foreign substances.
Epithelial cells are arranged in single, or multiple layers, depending on the organ and location.
Kierszenbaum AL, Tres LL. Epithelium. In: Kierszenbaum AL, Tres LL, eds. Histology and Cell Biology: An Introduction to Pathology. 4th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 1.
Review Date 10/8/2018
Updated by: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.