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DictionarySeeepitheliumCiliated Epithelium
ciliated epithelium[′sil·ē‚ād·əd ep·ə′thēl·ē·əm] (histology) Epithelium composed of cells bearing cilia on their free surfaces. Ciliated Epithelium in animals and man, epithelial tissue whose cells are furnished with cilia. The movements of the cilia of each epithelial cell and of the epithelial layer as a whole are closely coordinated. Each cilium is ahead of the next in its phase of movement by a certain length of time, so that the movement of the surface of the layer as a whole appears wavelike. Ciliated epithelium lines the respiratory passages, part of the genitourinary tract, the eustachian tube, part of the tympanic cavity, the central canal of the spinal cord, and the ventricles of the brain. In some animals it is found in the integuments (for locomotion) and in the alimentary canal. The motion of the cilia moves the liquid medium and the solid particles in it. Thus, for example, the cilia help remove dust from the respiratory passages. On the basis of electron microscopy, scientists have advanced hypotheses suggesting a link between the coordinated movement of the cilia and the breakdown of adenosine triphosphate (ATP). However, the phase of the movement (contraction or relaxation) at which the ATP is utilized has not yet been determined. REFERENCESShmagina, A. P. Mertsatel’noe dvizhenie. Moscow, 1948.
Arronet, N. I. Myshechnye i kletochnye sokratitel’nye (dvigatel’nye) modeli. Leningrad, 1971.M. E. ASPIZ ciliated epithelium
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.cil·i·at·ed ep·i·the·li·umany epithelium having motile cilia on the free surface.cil·i·at·ed ep·i·the·li·um (sil'ē-ā-tĕd ep'i-thē'lē-ŭm) Any epithelium having motile cilia on the free surface (e.g., bronchial epithelium). ciliated epithelium a sheet of cells (see EPITHELIUM) that carry cilia (see CILIUM) on the exposed surface. These cilia exhibit METACHRONAL RHYTHM and commonly move fluids about the bodies of animals, for example, in the respiratory passages of terrestrial vertebrates expelling dust or other foreign matter in microphagous animals. Ciliated epithelium is usually columnar and contains GOBLET CELLS for mucus production. |