epithelia


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Related to epithelia: epithelial tissue, connective tissue

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.

ep·i·the·li·a

(ep'i-thē'lē-ă),
Plural of epithelium.

epithelia

(ĕp′ə-thē′lē-ə)
n.
A plural of epithelium.

ep·i·the·li·a

(ep'i-thē'lē-ă)
Plural of epithelium.

epithelium

(ep?i-the'le-um) ('le-a) plural.epithelia [ epi- + Gr. thele, nipple, teat + -ium (2)]
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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), adjective

ciliated epithelium

Epithelium 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 epithelium

Epithelium composed of cylindrical cells.

cuboidal epithelium

Epithelium consisting of cube-shaped or prismatic cells with height about equal to their width.

germinal epithelium

1. 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 epithelium

Epithelium consisting of secretory cells.

junctional epithelium

A 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 cuff

laminated epithelium

Stratified epithelium.

mesenchymal epithelium

Squamous epithelium that lines the subarachnoid and subdural cavities, the chambers of the eye, and the perilymphatic spaces of the ear.

pavement epithelium

Epithelium consisting of flat, platelike cells in a single layer.

pigmented epithelium

Epithelium containing pigment granules.

pseudostratified epithelium

Epithelium 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 epithelium

Combined 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 epithelium

The flat form of epithelial cells.

stratified epithelium

Epithelium with the cells in layers; mitosis takes place in the lowest layer. Synonym: laminated epithelium

sulcular epithelium

The nonkeratinized epithelium that lines the gingival sulcus.

transitional epithelium

A 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).
References in periodicals archive ?
The p63 nuclear transcription factor, a p53 homologue, was proposed as a marker for limbal stem cells; in fact, it represents an essential determinant of the proliferative potential of stem cells in stratified epithelia [28, 41, 46-49].
The lining epithelia showed a negative expression pattern for CK18.
Different types of junctions in metazoan epithelia are specialized to adhere cells together, to mediate communication between them, and to impede passage of solutes between cells (Farquhar and Palade, 1963; Miller et al, 2013).
Such ultrastructural features are commonly exhibited by epithelia that specialize in ion and water transport from dilute media (Berridge & Oschman 1972).
Interestingly, epithelial tissues which are predominantly exposed to [H.sub.2]S, such as colon epithelia, have a particular high metabolic, [H.sub.2]S-detoxifying capacity [29, 30].
Relationship of cell formation and cell migration in the renewal of stratified squamous epithelia. Adv Biol Skin 2014; 5: 39-57.
The coexistence of both larval and adult epithelia was evident at stage 63 (Figure 4(g)).
To grow the artificial skin, the researchers the new type of epithelia covering and a biomaterial made of fibrin and agarose, already designed and developed by the team.
Keratins are defined as intermediate filament forming proteins with specific physicochemical properties produced in any vertebrate epithelia. (4) They are multigene family of proteins constituting 85% of the total cellular protein in the cornified cells of the epidermis and encoded by a family of approximately 30 proteins.
Since the corneal epithelium is of the stratified squamous type, autologous epithelial cells such as oral, conjunctival, nasal and oesophageal epithelia, all having a similar morphology, could be considered as an alternative to allogenous limbal transplants.
Brown said during the presentation, which was sponsored by the American Society for Microbiology, that there is reason to suspect protection might be different because the male and female epithelia are quite different, especially when comparing penile and cervical lesions.
The University of Iowa Research Foundation (Iowa City, IA) has patented a method for targeted delivery of a delivery vehicle construct which specifically binds to and stimulates endocytosis into cells expressing the urokinase plasminogen activator receptor (uPAR), and particularly human airway epithelia. The delivery vehicle construct comprises a portion of uPA and a cargo linked thereto and is useful for the targeted delivery of the cargo to a cell.