epidermis


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epidermis

 [ep″ĭ-der´mis] (pl. epider´mides) (Gr.)
the outermost and nonvascular layer of the skin, derived from the embryonic ectoderm, varying in thickness from 0.07 to 1.4 mm. On the palmar and plantar surfaces it comprises, from within outward, five layers: (1) basal layer (stratum basale), composed of columnar cells arranged perpendicularly; (2) prickle-cell or spinous layer (stratum spinosum), composed of flattened polyhedral cells with short processes or spines; (3) granular layer (stratum granulosum), composed of flattened granular cells; (4) clear layer (stratum lucidum), composed of several layers of clear, transparent cells in which the nuclei are indistinct or absent; and (5) horny layer (stratum corneum), composed of flattened, cornified, non-nucleated cells. In the epidermis of the general body surface, the clear layer is usually absent. adj., adj epider´mal, epider´mic.
Section of epidermis. From Dorland's, 2000.

ep·i·der·mis

, pl.

ep·i·derm·i·des

(ep'i-dĕrm'is, -derm'i-dēz), [TA]
1. The superficial epithelial portion of the skin (cutis). The thick epidermis of the palms and soles contains the following strata, from the surface: stratum corneum (keratin layer), stratum lucidum (clear layer), stratum granulosum (granular layer), stratum spinosum (prickle cell layer), and stratum basale (basal cell layer); in other parts of the body, the stratum lucidum and stratum granulosum may be absent.
2. In botany, the outermost layer of cells in leaves and the young parts of plants.
Synonym(s): cuticle (3) , cuticula (2) , epiderm, epiderma
[G. epidermis, the outer skin, fr. epi, on, + derma, skin]

epidermis

/epi·der·mis/ (-der´mis) pl. epider´mides   the outermost and nonvascular layer of the skin, derived from the embryonic ectoderm, varying in thickness from 0.07–1.4 mm. On the palmar and plantar surfaces it comprises, from within outward, five layers: (1) basal layer (stratum basale), composed of columnar cells arranged perpendicularly; (2) prickle cell or spinous layer (stratum spinosum), composed of flattened polyhedral cells with short processes or spines; (3) granular layer (stratum granulosum) composed of flattened granular cells; (4) clear layer (stratum lucidum), composed of several layers of clear, transparent cells in which the nuclei are indistinct or absent; and (5) horny layer (stratum corneum), composed of flattened, cornified, non-nucleated cells. In the epidermis of the general body surface, the clear layer is usually absent.epider´malepider´mic

epidermis

(ĕp′ĭ-dûr′mĭs)
n.
1. The outer, protective, nonvascular layer of the skin of vertebrates, covering the dermis.
2. An integument or outer layer of various invertebrates.
3. The outermost layer of cells covering the leaves and young parts of a plant.

ep′i·der′mal (-məl), ep′i·der′mic adj.

epidermis

[ep′idur′mis]
Etymology: Gk, epi + derma, skin
the superficial avascular layers of the skin, made up of an outer dead, cornified part and a deeper living, cellular part. Each layer is named for its unique function, texture, or position. The deepest layer is the stratum basale. It anchors the more superficial layers to the underlying tissues, and it provides new cells to replace those lost by abrasion from the outermost layer. The cells of each layer migrate upward as they mature. Above the stratum basale lies the stratum spinosum. As the cells migrate to the next layer, the stratum granulosum, they become flat, lying parallel with the surface of the skin. Over this layer lies a clear, thin band of homogenous tissue called the stratum lucidum. The outermost layer, the stratum corneum, is composed of scaly, squamous plaques of dead cells that contain keratin, a waterproofing protein that hardens over several days. This horny layer is thick over areas of the body subject to abrasion, such as the palms of the hands, and thin over other more protected areas. Altogether these layers are between 0.5 and 1.1 mm in thickness. Also called cuticle. See also skin. epidermal, epidermoid, adj.

ep·i·der·mis

, pl. epidermides (epi-dĕrmis, -mi-dēz)
1. The superficial epithelial portion of the skin (cutis). The epidermis of the palms and soles has the following strata: stratum corneum (horny layer), stratum lucidum (clear layer), stratum granulosum (granular layer), stratum spinosum (prickle cell layer), and stratum basale (basal cell layer); in other parts of the body, the stratum lucidum may be absent.
2. botany The outermost layer of cells in leaves and the young parts of plants.
Synonym(s): cuticle (3) , cuticula (2) .
[G. epidermis, the outer skin, fr. epi, on, + derma, skin]

epidermis

The structurally simple outermost layer of the skin, containing no nerves, blood vessels, or hair follicles, and acting as a rapidly replaceable surface. The deepest layer of the epidermis is the basal cell layer. Above this is the ‘prickle cell’ layer. The epidermis is ‘stratified’, the layers of cells becoming flatter towards the surface. The outermost cells of the epidermis are dead and are continuously shed.

epidermis

  1. (in plants) the thin tissue, usually one cell thick, that surrounds young roots, stems and leaves. In stems and leaves the epidermal cells secrete a CUTICLE (1), in roots they do not. In older roots and stems the epidermis is often replaced by CORK tissue.
  2. (in animals) the outer layer of the skin derived from embryonic ECTODERM. In vertebrates, the epidermal layer is usually made up of stratified EPITHELIUM with an outer layer of dead cells which become ‘keratinized’ (see KERATIN forming a protective layer. The invertebrate epidermis is normally one cell thick and often forms a protective cuticle.

Epidermis

The outer layer of skin, consisting of a layer of dead cells that perform a protective function and a second layer of dividing cells.

epidermis

stratified outer layer of skin (strata are named from deep to superficial as germinativum [or basale], granulosum, spinosum, lucidum and corneum), formed of ectoderm-derived cells, and giving rise to epidermal appendages (see gland, apocrine; gland, eccrine; hair follicle; nail)

ep·i·der·mis

, pl. epidermides (epi-dĕrmis, -mi-dēz)
[TA] The superficial epithelial portion of the skin (cutis).
[G. epidermis, the outer skin, fr. epi, on, + derma, skin]

epidermis

(ep´ider´mis),
n the superficial, avascular layers of the skin.

epidermis

the outermost and nonvascular layer of the skin, derived from the embryonic ectoderm, the thickness varying between species and in different locations on the body. There are generally five layers, from within outward: (1) basal layer (stratum basale), composed of columnar cells arranged perpendicularly; (2) prickle-cell or spinous layer (stratum spinosum), composed of flattened polyhedral cells with short processes or spines; (3) granular layer (stratum granulosum), composed of flattened granular cells; (4) clear layer (stratum lucidum), composed of several layers of clear, transparent cells in which the nuclei are indistinct or absent; and (5) horny layer (stratum corneum), composed of flattened, cornified, non-nucleated cells. The clear layer is only present in certain areas such as the footpads of dogs and cats and the planum nasale.

limbic epidermis
transitional epithelium between limb skin and hoof horn; covers the limbic corium.
perioplic epidermis
see limbic epidermis (above).
tubular epidermis
covering of the corium of the hoof coronet; produces the tubular horn of the hoof wall.
References in periodicals archive ?
The Effect of Topical SOP on the Epidermis Bax Proteins after UVB Irradiation.
Reconstructed human epidermis infected with Trichophyton rubrum conidia
All cases of atrophic LP had hyperkeratosis with an atrophic epidermis and focal basal cell destruction.
Mature leaves in the studied species are hypostomatic (Figure 2d) and present a unisseriate epidermis, with few tector and secretory trichomes.
Emollients, often called moisturisers have a number of functions; they soften and raise the moisture content within the epidermis, increase the skins resistance to irritation from outside irritants and improve pliability (Lorden, M.
The ratio of polar and equatorial diameters on the adaxial epidermis indicated greater functionality in the stomatal control of aperture mechanisms.
In regeneration-competent animals, the newly formed epidermis, which is termed the wound epidermis, is distinguishable from the surrounding epidermis by its thick morphology (Santos-Ruiz et al, 2002).
Garrod and his team used chemical cross-linking to study cells of the epidermis and found what they believe to be the principal mechanism by which the glue molecules of desmosomes of skin cells bind to each other.
The surface epidermis is frequently ulcerated or crusted, sometimes showing excoriation if the lesion has been manipulated, scratched, or traumatized prior to biopsy (figure 1).
The granular layer moves the dead keratin cells to the surface of the epidermis.
It's true we constantly form skin cells but mainly in the epidermis, the topmost layer.