Epithelium

Epithelium is a collective biological-medical term for covering tissue and glandular tissue. The epithelium is a covering tissue consisting of one or more layers of epithelial cells arranged almost without gaps, with little intercellular substance and containing no vessels.

Along with muscle tissue, nerve tissue and connective tissue, the epithelium is one of the four basic tissue types.

The epithelium is a protective organ and metabolic organ with the ability to resorb (e.g. alveolar epithelium) and secrete (gland), which covers the outer body surface (epidermis) or lines the hollow organs and body cavities (tunica mucosa, mesothelium, ependyma), as well as the highly differentiated sensory epithelium. They are distinguished by their shape as:

• monolayer squamous epithelium
• cubic and prismatic epithelium or also as
• multilayered or multilayered epithelium, i.e. consisting of several layers of cells of different heights, e.g. as multilayered squamous epithelium, as in the oral cavity.