| peritubular zone | The dentinal matrix surrounding the odontoblastic process; it is more highly calcified and contains finer collagen fibres than does the rest of the dentinal matrix. (05 Mar 2000) |
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| grenz zone | In histopathology, a narrow layer beneath the epidermis that is not infiltrated or involved in the same way as are the lower layers of the dermis. Origin: Ger. Grenze, borderline, boundary (05 Mar 2000) |
| choroidal vascular atrophy | Atrophy affecting either all choroidal vessels or only the choriocapillaris, occurring either diffusely or confined to the posterior pole of the eye. (05 Mar 2000) |
| ciliary zone | The outer, wider zone of the anterior surface of the iris, separated from the pupillary zone by the collarette. Synonym: zona ciliaris. (05 Mar 2000) |
| collagen-vascular diseases | A group of generalised disease's affecting connective tissue and frequently characterised by fibrinoid necrosis or vasculitis; in some collagen disease's, auto-immunization, particularly antinuclear antibodies, has been shown and circulating immune complexes are found. The term is not entirely acceptable because there is no evidence that collagen is primarily involved; "collagen" was once synonymous with "connective tissue" rather than describing a specific fibrinous protein in that tissue. See: connective-tissue diseases. (05 Mar 2000) |
| Weil's basal zone | The layer beneath the odontoblasts of the tooth; it contains reticular fibres but few if any cells. Synonym: Weil's basal zone. (05 Mar 2000) |
| Wernicke's zone | The region of the cerebral cortex thought to be essential for understanding and formulating coherent, propositional speech; it encompasses a large region of the parietal and temporal lobes near the lateral sulcus of the left cerebral hemisphere; corresponding approximately to Brodmann's areas 40, 39, and 22. Synonym: sensory speech centre, Wernicke's area, Wernicke's field, Wernicke's region, Wernicke's zone. (05 Mar 2000) |
| comfort zone | The temperature range between 28캜 and 30캜 at which the naked body is able to maintain the heat balance without either shivering or sweating; in the clothed body the range is from 13캜 to 21캜. (05 Mar 2000) |
| motor zone | That portion of the cerebral cortex, primarily the posterior region of the frontal lobe, near the central sulcus, which when stimulated produces a movement and when injured produces spasticity or paralysis. (05 Mar 2000) |
| muscle, smooth, vascular | The nonstriated, involuntary muscle tissue of blood vessels. (12 Dec 1998) |
| polar zone | The region in the vicinity of an electrode applied to the body. See: electrotonus. (05 Mar 2000) |
| haemorrhoidal zone | The part of the anal canal that contains the rectal venous plexus. Synonym: annulus haemorrhoidalis, zona haemorrhoidalis. (05 Mar 2000) |
| Haller's vascular tissue | <anatomy> The outer portion of the choroid of the eye containing the largest blood vessels. Synonym: lamina vasculosa choroideae, Haller's vascular tissue, uvaeformis, vascular layer of choroid coat of eye, vascular layer. (05 Mar 2000) |
| pregnancy zone proteins | Glycoproteins with the electrophoretic mobility of an alpha 2-globulin. They are found in small amounts in normal human plasma but in much larger volume in the plasma of pregnant women. These proteins have also been found in increased amounts in individuals undergoing oestrogen therapy and are sometimes produced ectopically by tumours of non-placental origin. Pregnancy zone proteins are believed to be of maternal rather than placental origin. (12 Dec 1998) |
| progress zone | An undifferentiated population of mesenchyme cells beneath the apical ectodermal ridge of the chick limb bud from which the sucessive parts of the limb are laid down in a proximo distal sequence. (18 Nov 1997) |