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epithelium[ep″ĭ-the´le-um] (pl. epithe´lia) (Gr.)
the cellular covering of internal and external surfaces of the body, including the lining of vessels and other small cavities. It consists of cells joined by small amounts of cementing substances. Epithelium is classified into types on the basis of the number of layers deep and the shape of the superficial cells.
ciliated epithelium epithelium bearing vibratile, hairlike processes (cilia) on its free surface.
columnar epithelium epithelium whose cells are of much greater height than width.
cuboidal epithelium epithelium whose cells are of approximately the same height and width, and appear square in transverse section.
germinal epithelium thickened peritoneal epithelium covering the gonad from earliest development; formerly thought to give rise to germ cells.
glandular epithelium that composed of secreting cells.
pigmentary epithelium (pigmented epithelium) that made of cells containing granules of pigment.
sense epithelium (sensory epithelium) neuroepithelium (def. 1).
simple epithelium that composed of a single layer of cells.
squamous epithelium that composed of flattened platelike cells.
stratified epithelium epithelium made up of cells arranged in layers.
transitional epithelium a type characteristically found lining hollow organs, such as the urinary bladder, that are subject to great mechanical change due to contraction and distention; originally thought to represent a transition between stratified squamous and columnar epithelium.
epithelium formed of a single layer of prismatic cells taller than they are wide.
Synonym(s): cylindric epithelium
Epithelium consisting of one or more cell layers, the most superficial of which is composed of elongated and somewhat cylindrical cells projecting toward the surface.
Etymology: L, columna, column; Gk, epi, upon, thele, nipple
a type of epithelial cell that resembles a hexagonal prism.
co·lum·nar ep·i·the·li·um(kō-lŭm'năr ep'i-thē'lē-ŭm)
Epithelium formed of a single layer of prismatic cells taller than they are wide.