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epithelial
ep·i·the·li·um E0184100 (ĕp′ə-thē′lē-əm)n. pl. ep·i·the·li·a (-lē-ə) or ep·i·the·li·ums Membranous tissue composed of one or more layers of cells separated by very little intercellular substance and forming the covering of most internal and external surfaces of the body and its organs.
[New Latin epithēlium : epi- + Greek thēlē, nipple; see dhē(i)- in Indo-European roots.]
ep′i·the′li·al adj.ep•i•the•li•al (ˌɛp əˈθi li əl)
adj. of the epithelium. [1840–50] Thesaurus| Adj. | 1. | epithelial - of or belonging to the epithelium; "epithelial layer" |
TranslationsEncyclopediaSeeepitheliumepithelial
epithelial [ep″ĭ-the´le-al] pertaining to or composed of epithelium.ep·i·the·li·al (ep'i-thē'lē-ăl), Relating to or consisting of epithelium.epithelial adjective Referring to epithelium, which lines internal and external surfaces of the body.ep·i·the·li·al (ep'i-thē'lē-ăl) Relating to or consisting of epithelium. epithelium (ep?i-the'le-um) ('le-a) plural.epithelia [ epi- + Gr. thele, nipple, teat + -ium (2)]  GLANDULAR EPITHELIUM: (Orig. mag. ×430)The layer of cells forming the epidermis of the skin and the surface layer of mucous and serous membranes. The cells rest on a basement membrane and lie in close approximation with little intercellular material between them. They are devoid of blood vessels. The epithelium may be simple, consisting of a single layer, or stratified, consisting of several layers. Cells making up the epithelium may be flat (squamous), cube-shaped (cuboidal), or cylindrical (columnar). Modified forms of epithelium include ciliated, pseudostratified, glandular, and neuroepithelium. The epithelium may include goblet cells, which secrete mucus. Stratified squamous epithelium may be keratinized for a protective function or abnormally keratinized in pathological response. Squamous epithelium is classified as endothelium, which lines the blood vessels and the heart, and mesothelium, which lines the serous cavities. Epithelium serves the general functions of protection, absorption, and secretion, and specialized functions such as movement of substances through ducts, production of germ cells, and reception of stimuli. Its ability to regenerate is excellent; it may replace itself as frequently as every 24 hr. See: illustration; skinepithelial (-al), adjectiveciliated epitheliumEpithelium with hairlike processes on the surface that wave actively only in one direction. This type is present in the respiratory tract and fallopian tubes. columnar epitheliumEpithelium composed of cylindrical cells. cuboidal epitheliumEpithelium consisting of cube-shaped or prismatic cells with height about equal to their width.germinal epithelium1. Epithelium that covers the surface of the genital ridge of the urogenital folds of an embryo. It gives rise to the seminiferous tubules of the testes and the surface layer of the ovary. It was once thought to produce the germ cells (spermatozoa and ova). 2. The epithelium that covers the surface of a mature mammalian ovary.glandular epitheliumEpithelium consisting of secretory cells. junctional epitheliumA band of nonkeratinized stratified squamous epithelium that attaches both to the gingiva (on one side) and the crown of the tooth (on the other). Synonym: epithelial attachment; gingival cufflaminated epitheliumStratified epithelium.mesenchymal epitheliumSquamous epithelium that lines the subarachnoid and subdural cavities, the chambers of the eye, and the perilymphatic spaces of the ear.pavement epitheliumEpithelium consisting of flat, platelike cells in a single layer.pigmented epitheliumEpithelium containing pigment granules. pseudostratified epitheliumEpithelium in which the bases of cells rest on the basement membrane but the distal ends of some do not reach the surface. Their nuclei lie at different levels, giving the appearance of stratification. reduced enamel epitheliumCombined epithelial layers of the enamel organ, which form a protective layer over the enamel crown as it erupts and then become the primary epithelial attachment surrounding the tooth.squamous epitheliumThe flat form of epithelial cells. stratified epitheliumEpithelium with the cells in layers; mitosis takes place in the lowest layer. Synonym: laminated epitheliumsulcular epitheliumThe nonkeratinized epithelium that lines the gingival sulcus.transitional epitheliumA form of stratified epithelium in which the cuboidal cells adjust to mechanical changes such as stretching and recoiling. This type of tissue is found only in the urinary system (renal pelvis, ureter, bladder, and a part of the urethra). ep·i·the·li·al (ep'i-thē'lē-ăl) Relating to or consisting of epithelium. |