CENTRE

n. Se2ntr. Gr., xevrpov. Lat., centrum. Fr., c. Ger., Centrum, Mittelpunkt. It., Sp., centra. 1. A point that is perfectly or approximately equidistant from all parts of the periphery of a surface or of the superficies of a solid. 2. The point of origin of a developmental proce (e. g., c. of o ification). 3. An area in the nervous system from which a special nervous impulse proceeds. Accelerating c. of the heart. See Cardio-acceleratory c. Acoustic c's. Fr., c's acoustiques. Ger., Gehorcentren, Horsphfire, Oehorkerne. 1. The c's of origin of the acoustic nerve: that region of the encephalon which includes portions of the cerebellar peduncles, the floor of the fourth ventricle, the funiculus cuneatus, the funiculus gracilis, the restiform body, and the striae medulla res. [F.] Cf. Auditory NUCLEUS. 2. The sensory c. of the acoustic nerve; a region situated in the posterior two thirds of the superior temporal convolution (Wernicke's convolution). Lesions Fr., c. ano-spinal. A nervous c. in the lumbar portion of the spinal cord, presiding over the contractions of the sphincter ani. [K: L, 49.] Aiio-vesical c. Lat., centrum ano-vesicale. The c. in the spinal cord which regulates the tonicity of the sphincter ani and of the sphincter of the bladder; situated, according to Stilling and Kirchoff, in the lumbar enlargement, near the point of origin of the third and fourth sacral nerves. Paralysis of this c. produces incontinence of faeces and of urine. [Kirchoff, " Jour, of Ment. Sci.," April, 1886, p. 126 (a, 18).] Arm-c. That one of the cerebral c's that is supposed to govern the movements of the arm; an area of the cortex occupying the middle third of both central convolutions (gyrus central is anterior and gyrus central is posticus), and also the base of the superior and middle frontal convolutions. Excitation of this c. produces movements in the arm of the opposite side. [ Mendel (A, 319 [a, 18]); A, 481 (a, 18); Wig les worth, "Liverpool Med.- chir. Jour.," Jan., 1885. p. 60.] Arrest c. of the heart. See Cardio-inhibitory c. Articulate-language c. See Speech-co-ordinating c. Auditory c. Lat., centrum auditivum. Yr..c.audit if. Ger., Gehorccntrum. A region in the cerebrum to which auditory impulses are transmitted; located by Ferrier in the infra marginal convolution. [K, 3.] Cf. Acoustic c's. Broca's c. See Kinas thetic c. Budge's c. See Genito-s) inal c. Bulbar trophic c. Fr., c. trophi que bulbaire. The bulbar vaso-motor c., variously placed by different authors between a point situated 2 mm. below the corpora quadrigemina and one situated 5 mm. above the calamus script on us. Exce of carbon dioxide and diminution of oxygen in the blood excite this c. to increased action, [a, 18.] Cardiac c. Fr., c. cardia que. Ger., Herzcentrum. 1. The region in the medulla oblong at a that includes the cardio-acceleratory and the cardio-inhibitory c's (q. v.). 2. An excito-motor nervous c. influencing the movements of the heart: situated in the lower cervical and upper dorsal portions of the spinal cord, [a, 18.] See Caraz'oacceleratory c. and Cardio-inhibitory c. Cardio-accelerating (or acceleratory) c. An area in the medulla oblong at a from which fibres proceed down the cervical portion of the spinal cord to the lower cervical and upper dorsal ganglia of the sympathetic E, he; E, ell; G, go; I, die; Ia, in; N, in; N, tank; [s. 164]