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
epidermis
epidermis [ep″ĭ-der´mis] (pl. epider´mides) (Gr.)
ep·i·der·mis ( p  -dûr ms)n. The nonvascular outer protective layer of the skin, covering the dermis. ep i·dermal (-m l), epi·dermic adj. |
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.
Mentioned in: Burns, Epidermolysis Bullosa, Malignant Melanoma, Skin Grafting, Staphylococcal Scalded Skin Syndrome, Toxic Epidermal Necrolysis, Warts
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.
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.
epidermis
(ep´ider´mis),
n the superficial, avascular layers of the skin.
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.
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