lépithélium

Lépithélium is not a standard anatomical term in most languages. In French, the correct term is épithélium; in English, epithelium. When lépithélium appears in texts, it is usually a misspelling or variant of épithélium. The article below describes epithelial tissue, which is the concept behind the term.

Epithelial tissue lines all external and internal surfaces, forms the parenchyma of glands, and covers the body. It consists of closely packed cells with minimal extracellular matrix, shows apical-basal polarity, sits on a basement membrane, is avascular, and regenerates readily after injury.

Classification is based on several criteria: by number of cell layers (simple, stratified, pseudostratified); by shape (squamous, cuboidal, columnar); and by function (glandular, ciliated, sensory epithelia). Each type has characteristic features suited to its role in protection, secretion, absorption, and filtration.

Functions include protection from mechanical and chemical stress, selective permeability, absorption of nutrients, secretion of mucus and enzymes, and, in certain cases, sensation. Epithelial cells are joined by junctional complexes such as tight junctions, adherens junctions, desmosomes, and gap junctions, and they rest on a basement membrane that anchors the tissue to underlying connective tissue.

Common locations include the skin epidermis (stratified squamous), the lining of the intestine (simple columnar), the respiratory tract (pseudostratified ciliated columnar), and ducts of various glands. Clinically, epithelial tissues can undergo metaplasia and dysplasia and may give rise to carcinomas, such as squamous cell carcinoma and adenocarcinoma.

See also: epithelium, mucosa, basement membrane.