| basal cell nevus | A hereditary disease noted in infancy or adolescence, characterised by lesions of the eyelids, nose, cheeks, neck, and axillae, appearing as uneroded flesh-coloured papules, some becoming pedunculated, and histologically indistinguishable from basal cell epithelioma; also noted are punctate keratotic lesions of the palms and soles; the lesions usually remain benign, but in some cases ulceration and invasion occur and are evidence of malignant change; autosomal dominant inheritance. (05 Mar 2000) |
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| basal cell nevus syndrome | <syndrome> An inherited group of defects which involve abnormalities of the skin, eyes, nervous system, endocrine, glands and bones. The condition is characterised by an unusual facial appearance and a predisposition for skin cancer. (27 Sep 1997) |
| basal cell papilloma | A benign skin lesion resulting from excessive growth of the top layer of skin cells. It usually is found in persons over 30 years old and may be few or numerous. (12 Dec 1998) |
| basal cells | Small, round cells found in the lower part, or base, of the epidermis, the outer layer of the skin. (12 Dec 1998) |
| basal cistern | A dilation of the subarachnoid space in front of the pons, where the arachnoid membrane stretches across between the two temporal lobes over the base of the diencephalon. See: interpeduncular fossa. Synonym: cisterna interpeduncularis, basal cistern, cisterna basalis, cisterna cruralis, Tarin's space. (05 Mar 2000) |
| basal corpuscle | <cell biology> Structure found at the base of eukaryotic cilia and flagella consisting of a continuation of the nine outer sets of axonemal microtubules but with the addition of a C tubule to form a triplet (like the centriole). May be self replicating and serves as a nucleating centre for axonemal assembly. Anchored in the cytoplasm by rootlets. Synonymous with kinetosome. (18 Nov 1997) |
| basal diet | A diet having a caloric value equal to the basal heat production and sufficient quanties of essential nutrients to meet basic needs, in experiments in nutrition, a diet from which a given constituent (e.g., a vitamin, mineral, or amino acid), the nutritional value of which is to be determined, is omitted for a period and the effects observed; the subject is observed for a second period during which the ingredient being studied is added to the diet. (05 Mar 2000) |
| basal ganglia | <anatomy> Three large subcortical nuclei of the vertebrate brain: the putamen, the caudate nucleus and the globus pallidus. They participate in the control of movement along with the cerebellum, the corticospinal system and other descending motor systems. Lesions of the basal ganglia occur in a variety of motor disorders including Parkinson's disease and Huntingdon's chorea. (15 Nov 1997) |
| basal ganglia calcification | <radiology> Idiopathic: normal variant (50%), abnormal calcium metabolism, hyperparathyroidism, hypo-, pseudohypo-, and pseudo-pseudohypoparathyroidism, ToRCHS infection (especially CMV, toxo), tuberous sclerosis, Cockayne syndrome, Fahr syndrome (ferrocalcinosis), lipoid proteinosis (hyalinosis cutis) (12 Dec 1998) |
| basal gland | pituitary gland |
| basal granule | <cell biology> Structure found at the base of eukaryotic cilia and flagella consisting of a continuation of the nine outer sets of axonemal microtubules but with the addition of a C tubule to form a triplet (like the centriole). May be self replicating and serves as a nucleating centre for axonemal assembly. Anchored in the cytoplasm by rootlets. Synonymous with kinetosome. (18 Nov 1997) |
| basal joint reflex | Opposition and adduction of the thumb with flexion at its metacarpophalangeal joint and extension at its interphalangeal joint, when firm passive flexion of the third, fourth, or fifth finger is made; the reflex is present normally but is absent in pyramidal lesions. Synonym: finger-thumb reflex, Mayer's reflex. (05 Mar 2000) |
| basal lamina | <cell biology> Extracellular matrix characteristically found under epithelial cells. There are two distinct layers: the basal lamina, immediately adjacent to the cells, is a product of the epithelial cells themselves and contains collagen type IV and the reticular lamina is produced by fibroblasts of the underlying connective tissue and contains fibrillar collagen. (15 Nov 1997) |
| basal lamina of choroid | The transparent, nearly structureless inner layer of the choroid in contact with the pigmented layer of the retina. Synonym: basal lamina of choroid, basal layer of choroid, Bruch's membrane, Henle's membrane, lamina vitrea, vitreous lamella, vitreous membrane. (05 Mar 2000) |
| basal lamina of ciliary body | The inner layer of the ciliary body, continuous with the basal layer of the choroid and supporting the pigment epithelium of the ciliary retina. Synonym: lamina basalis corporis ciliaris, basal layer of ciliary body. (05 Mar 2000) |