epithelium /ep·i·the·li·um/ (-the´le-um) pl. epithe´lia [Gr.] the cellular covering of internal and external body surfaces, including the lining of vessels and small cavities. It consists of cells joined by small amounts of cementing substances and is classified according to the number of layers and the shape of the cells.
Epithelium
epithelium
epithelium (ep´ithē´lē
m),
ciliated epithelium that bearing vibratile cilia on the free surface.
columnar epithelium that composed of columnar cells.
cuboidal epithelium that composed of cuboidal cells.
glandular epithelium that composed of secreting cells.
olfactory epithelium pseudostratified epithelium lining the olfactory region of the nasal cavity and containing the receptors for the sense of smell. 
)
Schematic diagram of the receptors in the olfactory epithelium.
pseudostratified epithelium a type that looks stratified but is not, because its cells are arranged with their nuclei at different levels.
seminiferous epithelium stratified epithelium lining the seminiferous tubules of the testis.
simple epithelium that composed of a single layer of cells.
squamous epithelium that composed of squamous cells.
stratified epithelium that composed of cells arranged in layers.
transitional epithelium that characteristically found lining hollow organs that are subject to great mechanical change due to contraction and distention; originally thought to represent a transition between stratified squamous and columnar epithelium.
ep·i·the·li·um ( p  -th  l-m)n. pl. ep·i·the·li·a (-l -) 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. ep i·theli·al adj. |
Epithelium
Cells composing the lining of an organ.
Mentioned in: Colon Cancer, Rectal Cancer
epithelium
[-thē′lē·əm]
Etymology: Gk, epi + thele, nipple
the covering of the internal and external organs of the body and the lining of vessels, body cavities, glands, and organs. It consists of cells bound together by connective material and varies in the number of layers and the kinds of cells. The stratified squamous epithelium of the epidermis comprises five different cellular layers. epithelial, adj.
epithelium (ep´ithē´lē
m),n the layer of cells that lines a body cavity; cells may be ciliated or unciliated, and may be squamous (flat, scalelike), cuboidal (cube-shaped), or columnar (column-shaped).
epithelium, basement membrane of,
n See membrane, basement.
epithelium, desmosomes of
(dez´mosōmz´),
n an electronmicroscopic finding of intercellular bridges that serve to attach adjacent epithelial cells to each other.
n an electronmicroscopic finding of intercellular bridges that serve to attach adjacent epithelial cells to each other.
epithelium, enamel, inner,
n the innermost layer of cells (ameloblasts) of the enamel organ that deposit the organic matrix of the enamel on the crown of the developing tooth. Also the innermost layer of Hertwig's epithelial root sheath.
epithelium, enamel, outer,
n the outermost layer of cells of the enamel organ. It is separated from the inner enamel epithelium in the area of the developing crown by the stratum intermedium and stellate reticulum and lies immediately adjacent to the inner enamel epithelium in the area of the developing root.
epithelium, enamel, reduced,
n combined enamel epithelium; the remains of the enamel organ after enamel formation is complete. After eruption of the tip of the crown, that part of the combined epithelium remaining on the enamel surface is called the
epithelial attachment.
epithelial attachment.
epithelium, gingival,
n a stratified squamous epithelium consisting of a basal layer; it is keratinized or parakeratinized.
epithelium, hyperplastic,
n an increase in thickness, with alterations in structure, produced by proliferation of cellular elements of epithelium.
epithelium, oral,
n the epithelial covering of the oral mucosa. Composed of stratified squamous epithelium of varying thickness and varying degrees of keratinization.
epithelium, pocket,
n the epithelium that lines the periodontal pocket. Its most prominent characteristics are the presence of hyperplasia and ulceration.
epithelium, pseudostratified
(soo´dōstrat´ifīd),
n a type of epithelium in which there appears to be several layers (or strata) of cells, but all cells actually are resting on the base layer. Often ciliated and occurs only in mucosa.
n a type of epithelium in which there appears to be several layers (or strata) of cells, but all cells actually are resting on the base layer. Often ciliated and occurs only in mucosa.
epithelium, squamous
n a type of epithelium consisting of flat, scalelike cells.
epithelium, stratified squamous,
n the variety of epithelium covering the oral mucosa and dermal surfaces; composed of layers of cells oriented parallel to the surface. The various layers of cells in order from basement membrane to surface are stratum germinativum, stratum spinosum (prickle cell layer), and stratum lucidum (in dermal epithelium). The gingival epithelium generally exhibits some degree of keratinization, variable from parakeratinization to orthokeratinization within the layers of the stratum granulosum (granular layer) and stratum corneum (keratin layer).
epithelium, sulcal,
n the stratified squamous epithelium forming the covering of the soft tissue wall of the gingival sulcus, or crevice. Extends from the gingival margin to the line of attachment of the epithelium to the tooth surface.
epithelium
pl. epithelia [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. Standard classifications include ciliated (cilia attached), columnar (taller than wide), cuboidal (same height as width), pseudostratified (single layer but because of varying cell height appears to be more than one), simple (one cell layer), squamous (flattened, plate-like cells), stratified (more than one layer), transitional (variable number of layers apparent). Other types are listed below.
anterior epithelium
the thin layer of stratified squamous cells that form the outermost layer of the cornea.
corneal epithelium
see anterior epithelium (above).
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.
lens epithelium
cuboidal epithelium covering the lens.
pigmentary epithelium, pigmented epithelium
that made of cells containing granules of pigment.
posterior epithelium
the single layer of epithelial cells on the back of the cornea, between stroma and aqueous humour; the corneal endothelium.
retinal pigment epithelium
see retina.
sense epithelium, sensory epithelium
see neuroepithelium (1).
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