stratum (redirected from Strata (geology))

stratum /stra·tum/ (strat´um) (stra´tum) pl. stra´ta   [L.] a layer or lamina.

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stratum basa´le  basal layer: the deepest layer, as of the endometrium or epidermis.

stratum compac´tum  compact layer of endometrium: the sublayer of the stratum functionale facing the interior of the uterus and containing the necks of the uterine glands.

stratum cor´neum  horny layer: the outermost layer of the epidermis, consisting of dead and desquamating cells.

stratum functiona´le  functional layer of endometrium: the layer of endometrium facing the uterine lumen, overlying the stratum basale; subdivided into the stratum compactum and stratum spongiosum. Its cells are cast off at menstruation and parturition. It is called the decidua during pregnancy.

stratum germinati´vum  germinative layer: the stratum basale and stratum spinosum of the epidermis considered as a single layer; the term is sometimes used to denote only the stratum basale.

stratum granulo´sum  granular layer.

1. the layer of epidermis between the stratum lucidum and stratum spinosum.

2. the layer of follicle cells lining the theca of the vesicular ovarian follicles.

stratum lu´cidum  clear layer: in the epidermis, the clear translucent layer just beneath the stratum corneum.

stratum spino´sum  spinous or prickle cell layer: in the epidermis, the layer between the stratum granulosum and stratum basale, characterized by the presence of prickle cells.

stratum spongio´sum  spongy layer of endometrium: the sublayer of the stratum functionale underlying the stratum compactum; it contains the tortuous portions of the uterine glands.

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stra·tum (strtm, strtm)

n. pl. stra·tums or stra·ta (-t)

1. A horizontal layer of material, especially one of several parallel layers arranged one on top of another.

2. Any of the layers of differentiated tissue forming an anatomical structure.

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stratal (-tl) adj.

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stratum

[strā′təm, strat′əm] pl. strata

Etymology: L, layer

a uniformly thick sheet or layer, usually associated with other layers, such as the stratum basale of the epidermis.

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stratum, (strat´m),

n.pl (
pl
strata) a layer of the epidermis or the epithelium of the oral mucosa.

stratum basale,

n the deepest of the five layers of the epidermis or epithelium of the oral mucosa, composed of a single layer of tall cylindrical cells or cubodial cells, respectively. This layer provides new cells by mitotic cell division. Also called the
basal layer or
germative layer.

stratum corneum,

n the tough, outermost layer of the epidermis or epithelium of keratinized oral mucosa, composed of flat, closely packed, dead cells converted to keratin that continually flake away. Also called the
keratin layer or
corneal layer.

stratum granulosum,

n one of the layers of the epidermis or the epithelium of the keratinized oral mucosa, situated just inferior to the stratum corneum in keratinized tissues except in the palms of the hands and the soles of the feet, where it lies just inferior to the stratum lucidum (transparent layer). Also called the
granular layer.

stratum intermedium,

n one of the two layers between the outer and inner enamel epithelium of the enamel organ that consists of a compressed layer of flat to cubodial cells.

stratum lucidum

n one of the layers of the epidermis situated just beneath the stratum corneum and present only in the thick skin of the palms of the hands and the soles of the feet. Also called the
transparent layer.

stratum spinosum,

n one of the layers of the epidermis or epithelium of oral mucosa, composed of several layers of polygonal cells. It lies on superior to the stratum basale. Also called the
prickle cell layer.

stratum spongiosum,

n one of the three layers of the endometrium of the uterus.

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stratum

pl. strata [L.] a sheetlike mass of tissue of fairly uniform thickness; distinct layers making up various tissues or organs, as of the skin, brain, retina.

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stratum avasculosum

the avascular stratum in the margin of the iris.

stratum basale

the mitotically active, basal layer of the epidermis, consisting of columnar to cuboidal keratinocytes on a basement membrane.

stratum corneum

the outer horny layer of the epidermis, consisting of cells that are non-nucleated, keratinized and desquamating.

stratum germinativum

in the epidermis, located between the stratum basale and the stratum granulosum. Together with the basal layer, called the malpighian layer. Called also germinative layer.

stratum granulosum

1. the layer of cells between the stratum lucidum and the stratum spinosum of the skin, very thin and not always present. Called also the granular layer.

2. the deep layer of the cortex of the cerebellum.

3. the layer of follicle cells lining the theca of the vesicular ovarian follicle. Called also granular layer.

stratum lamellatum

laminae of the hoof corium.

stratum lucidum

the translucent layer of the skin just beneath the stratum corneum. Called also clear layer. Present in the epidermis of the planum nasale of several species and footpads of carnivores.

stratum spinosum

the layer of the epidermis between the stratum granulosum and the stratum basale, marked by the presence of prickle cells; called also spinous layer and prickle-cell layer.

stratum tectorium

the layer of horny scales claimed to exist on the surface of the horse's hoof that gives it the smooth glossy appearance.