| gyracanthus | <paleontology> A genus of fossil fishes, found in Devonian and carboniferous strata; so named from their round, sculptured spines. Origin: NL, fr. Gr, round + spine. Source: Websters Dictionary (01 Mar 1998) |
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| gyral | 1. Moving in a circular path or way; whirling; gyratory. 2. <anatomy> Pertaining to a gyrus, or convolution. See: Gyre. Source: Websters Dictionary (01 Mar 1998) |
| gyral brain calcification | <radiology> Sturge-Weber-Dimitri syndrome, treated CNS lymphoma, post-meningoencephalitis, brain tumour (oligodendroglioma) (12 Dec 1998) |
| gyrase | The procaryotic topoisomerase II that utilises ATP to generate negative supercoils of DNA. Origin: L. Gyro, to turn in a circle, fr. Gyrus, G. Gyros (05 Mar 2000) |
| gyrate | 1. Of a convoluted or ring shape. 2. To revolve. Origin: L. Gyro, pp. Gyratus, to turn round in a circle, gyrus (05 Mar 2000) |
| gyrate atrophy | Progressive, autosomal recessive, diffuse atrophy of the choroid, pigment epithelium, and sensory retina that begins in childhood. (12 Dec 1998) |
| gyrate atrophy of choroid and retina | A slowly progressive atrophy of the choriocapillaris, pigmentary epithelium, and sensory retina, with irregular confluent atrophic areas and an associated ornithinuria; autosomal recessive inheritance; due to a deficiency of ornithine d-aminotransferase. (05 Mar 2000) |
| gyration | 1. The act of turning or whirling, as around a fixed center; a circular or spiral motion; motion about an axis; rotation; revolution. "The gyrations of an ascending balloon." (De Quincey) "If a burning coal be nimbly moved round in a circle, with gyrations continually repeated, the whole circle will appear like fire." (Sir I. Newton) 2. <zoology> One of the whorls of a spiral univalve shell. Center of gyration. 3. <physics> Radius of gyration the distance between the axis of a rotating body and its center of gyration. Source: Websters Dictionary (01 Mar 1998) |
| gyrectomy | Excision of a cerebral gyrus. Origin: G. Gyros, ring, + ektome, excision (05 Mar 2000) |
| gyrencephala | <zoology> The higher orders of Mammalia, in which the cerebrum is convoluted. Origin: NL. Fr. Gr. Round+ the brain. Source: Websters Dictionary (01 Mar 1998) |
| gyrencephalic | Denoting brains, such as that of humans, in which the cerebral cortex has convolutions, in contrast to the lissencephalic (smooth) brains of small mammals such as the rodents. Origin: G. Gyros, ring (gyrus), + enkaphale, brain (05 Mar 2000) |
| gyrfalcon | <zoology> One of several species and varieties of large Arctic falcons, especially. Falco rusticolus and the white species F. Islandicus, both of which are circumpolar. The black and the gray are varieties of the former. Alternative forms: gerfalcon, gierfalcon, and jerfalcon. Origin: OE. Gerfaucon, OF. Gerfaucon, LL. Gyrofalco, perh. Fr. L. Gyrus circle + falco falcon, and named from its circling flight; or cf. E. Gier-eagle. See Gyre, Falcon. Source: Websters Dictionary (01 Mar 1998) |
| gyri | Plural of gyrus. Origin: L. (05 Mar 2000) |
| gyri breves insulae | Several short, radiating gyri converging toward the base of the insula, composing the anterior two-thirds of the insular cortex. Synonym: gyri breves insulae. (05 Mar 2000) |
| gyri insulae | The short gyri of insula and long gyrus of insula. Synonym: gyri insulae. (05 Mar 2000) |