basal layer

strat·um ba·sa·'le

1. the outermost layer of the endometrium that undergoes only minimal changes during the menstrual cycle; Synonym(s): basal layer

2. Synonym(s): stratum basale epidermidis

basal layer

See stratum basale.

basal layer

(1) Bruch’s membrane, basal complex (of choroid); complexus basalis (choroideae) [NA6]; basal lamina of choroid; lamina basalis choroideae [NA6].
(2) Basement membrane; membrana basalis [NH3]. 
(3) Endometrial basal layer; stratum basale endometriale [NH3].

stra·tum ba·sa·le

(strā'tŭm bā-sā'lē)

1. The outermost layer of the endometrium, which undergoes only minimal changes during the menstrual cycle.
Synonym(s): basal layer.

2. Synonym(s): stratum basale epidermidis.

stratum basale

; stratum germinativum; germinal layer; basal layer deepest layer of the epidermis lying at dermoepidermal junction, keratinocytes and melanosomes Table 1

Table 1: Constituents of skin

Constituent	Components
Epidermis	Stratified squamous epithelium formed from keratinocytes Basal layer: keratinocytes linked by desmosomal and hemidesmosomal and filamentous connections (cytoskeleton; prevents shear) Spinous layer: keratinocytes shrink, retaining contact only at desmosomes and hemidesmosomes Granular layer: keratinocytes secrete complex lipids which act as a semipermeable skin barrier Corneal layer: cell and contents have become keratin to form squames moved towards the exterior
Epidermal cells	Keratinocytes Melanocytes: lie between keratinocytes; secrete pigment and protect keratinocyte nuclei from ultraviolet radiation Merkel cells: sensory cells Langerhans cells: within spinous layer; antigen-presenting cells
Basement membrane zone	Collagen, hemidesmosomes, laminin which aid adhesion of epidermis to dermis; dysfunctional in disease such as epidermolysis bullosa
Dermis	Mesodermal tissue containing blood vessels, nerve, muscle, skin appendages (sweat glands, sebaceous glands, hair follicles), immune cells (histamine-releasing mast cells) in a matrix of collagen, elastin and hyaluronic acid
Subcutaneous layer	Adipose tissue, blood vessels and nerves, acting as an insulating layer

stra·tum ba·sa·le

(strā'tŭm bā-sā'lē)

1. The outermost layer of the endometrium that undergoes only minimal changes during the menstrual cycle;
Synonym(s): basal layer.

2. Synonym(s): stratum basale epidermidis.

basal

pertaining to or situated near a base; in physiology, pertaining to the lowest possible level.

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basal body

the structure that acts as a template for the characteristic 9 + 2 arrangement of the microtubules of eukaryotic cilia and flagella.

basal cell tumors

neoplasms of the multipotential cells within the stratum germinativum of the skin. They are common in dogs and cats, are locally expansive and do not metastasize.

basal energy requirements (BER)

see energy requirements.

basal ganglia

a collection of masses of gray matter at the base of the cerebral hemispheres, subthalamus and midbrain which are responsible for much of the organization of the activity of somatic muscles. The individual nuclei are the caudate nucleus, putamen, globus pallidus, endopeduncular nucleus, subthalamic nucleus and the substantia nigra. Other nuclei which have a similar function but are usually not included in the group are the amygdaloid nuclei and the red nucleus.

basal layer

see stratum basale.

basal membrane

the deepest layer of the epidermis in the avian skin. Called also dermoepidermal junction.

basal metabolic rate

see metabolic rate.

basal metabolism

the minimal energy expended for the maintenance of respiration, circulation, peristalsis, muscle tonus, body temperature, glandular activity and the other vegetative functions of the body. See also metabolic rate.

basal metabolism test

a method of measuring the body's expenditure of energy by recording its rate of oxygen intake and consumption. Once a major test of thyroid gland function, it is being replaced by diagnostic tests requiring less extensive preparation and capable of producing more accurate test results, e.g. the determination of the levels of thyroid hormones in the blood and the radioiodine uptake test.

basal nuclei

see basal ganglion.

basal plate

the ventral plate of the developing neural tube of the embryo; associated with motor output from the CNS.

basal tone

degree of contractile tension remaining in blood vessels after complete elimination of all external excitatory influences.

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layer

1. stratum; a sheetlike mass of tissue of nearly uniform thickness, several of which may be superimposed, one above the other, as in the epidermis.

2. a commercial fowl which is laying eggs, i.e. a female of more than about 5 months of age, up to the stage of being a 'spent hen' suitable only for slaughter.

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basal layer

1. the deepest layer of the epidermis. See also stratum basale.

2. the deepest layer of the uterine mucosa.

blastodermic layer

germ layer (see below).

clear layer

stratum lucidum; the clear translucent layer of the epidermis, just beneath the horny layer.

columnar layer

1. layer of rods and cones.

2. mantle layer.

compact layer

the layer of the endometrium nearest the surface, containing the necks of the uterine glands.

functional layer

the compact and spongy layers of the endometrium considered together.

cerebellar ganglionic layer

the thin middle gray layer of the cortex of the cerebellum, consisting of a single layer of Purkinje cells.

germ layer

any of the three primary layers of cells formed in the early development of the embryo (ectoderm, entoderm and mesoderm), from which the organs and tissues develop.

germinative layer

any proliferative layer such as the basal layer of the epidermis or the lower layer of the claw, from which the claw grows.

granular layer

1. the layer of epidermis between the clear and prickle-cell layers; called also stratum granulosum.

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

3. the layer of follicle cells lining the theca of the vesicular ovarian follicle.

horny layer

1. stratum corneum; the outermost layer of the epidermis, consisting of dead and desquamating cells.

2. the outer, compact layer of the claw, etc.

keratohyaline layer

granular layer (1).

mantle layer

the middle layer of the wall of the primitive neural tube, containing primitive nerve cells and later forming the gray matter of the central nervous system.

nervous layer

all of the retina except the pigment layer; the inner layer of the optic cup.

prickle-cell layer

stratum spinosum; the layer of the epidermis between the granular and basal layers, marked by the presence of prickle cells.

layer of rods and cones

a layer of the retina immediately beneath the pigment epithelium, between it and the external limiting membrane, containing the rods and cones.

spinous layer

prickle-cell layer.

spongy layer

the middle layer of the endometrium, containing the tortuous portions of the uterine glands.

subendocardial layer

the layer of loose fibrous tissue uniting the endocardium and myocardium.

zonal layer of thalamus

a layer of myelinated fibers covering the dorsal surface of the thalamus.