Center

(sen'-ter) [centrum, the center]. 1. The middle point of any surface or of a body. 2. The ganglion or plexus whence issue the nerves controlling a function. C, Accel- erating, a center in the medulla sending accelerating fibers to the heart. These leave the cord through the branches of communica- tion of the lower cervical and upper six dorsal nerves, passing thence into the sympathetic. C, Anovesical, one in the spinal cord near the point of origin of the third and fourth sacral nerves. Incontinence of urine and feces is due to paralysis of this center. C, Arm, the cortical center controlling the movement of the arm, supposed to be in the cortex occupying the middle third of the anterior and posterior central gyri as well as the base of the superior and middle frontal gyri. C, Articulate Language, the speech- coordinating center, which is supposed to * CENTER 259 * CENTER include Broca's gyrus, the anterior gyri of the insula, the intervening cortical area, the supramarginal gyrus, the first temporal gyrus, and the angular gyrus. C, Auditory, a center in the first temporosphenoid con- volution upon each side. C, Broca's. See C, Speech. C, Cardiac, i. One in the lower cervical and upper dorsal portions of the spinal cord which controls the move- ments of the heart. 2. That portion of the oblongata embracing" the cardioaccelerator and cardioinhibitory centers. C, Cardio- accelerator, that of the spinal cord which through the cardiac nerves and plexus sends impulses to the heart, causing it to beat more rapidly. These impulses are not con- stantly emitted, as are the inhibitory im- pulses which travel by the pneumogastric. C, Cardioinhibitory, in the medulla, efferent impulses being carried by the vagus. C, Cerebral Inspiratory, one said to exist in the thalamus, which by direct stimulation causes deeper and more rapid inspirations. C, Cerebrospinal, the cere- brospinal axis. C, Ciliospinal, connected with the dilation of the pupil; it is in the lower cervical part of the cord, and extends downward from the first to the third dorsal. C, Color, a center for perception of colors, said to be situated in the occipital cortex anterior to the apical region. C, * Convulsional, a hypothetic center said to lie in the floor of the fourth ventricle. C, * Coordinating, the cerebellum, the ganglions at the base of the brain, and in some degree the cinerea of the spinal cord, are regarded as controlling coordination. C, Cortical, the parts of the cerebral cortex concerned in motor, sensory, and psychic functions. C, * Coughing, in the medulla, above the inspi- ratory center. C, Deglutition. See C., Swallowing. C, Deputy, a secondary gan- glion-cell in the spinal cord; also a nucleus of one of the cranial nerves. C, Diabetic, in the posterior part of the anterior half of the floor of the fourth ventricle, in the median line. C, Erection. See C, Genitourinary. C, Excitomotor, the sensitive centers of the brain considered as one; these are the crura, the pons, the oblongata, the deeper parts of the cerebellum, and the corpora quadrigemina. C.s, Facial Movement, one in the ascending frontal gyrus and one in the angular gyrus. C, Genitourinary, one in the lumbar portion of the spinal cord, but controlled from the medulla, controlling erection of the penis and emis- sion of semen. C, Glycogenic, the diabetic center. C, Half -vision, one in the apex of the occipital lobe, receiving im- pressions from corresponding halves of the two retinas. C, Head and Neck Move- ment, one in the posterior end of the second frontal gyrus and in the corresponding part of the first frontal gyrus. C, Heat-regu- lating, C, Temperature, the center for the control of body-temperature. See C, Ther- motaxic. C, Higher Visual, one regarded as lying in the angular gyrus, in which there is effected a combination of the impressions received from the half-vision centers, making a complete image. C, Hitzig's, a center in the supramarginal gyrus which is supposed to govern the voluntary movements of the eyeballs. C.s of Inhibition, C.s, Inhibitory. See C.s 0} Moderation. C., Inspiratory. 1. A reflex center in the oblongata forming part of the respiratory center. 2. See C, * Cerebral Inspiratory. 3. A reflex center in the postgeminum. C, Intracardiac, three small nerve-ganglions connected with the cardiac plexus, to which is due the automatic beating of the heart after separation from the body. C, Kinesthetic, one in the third left frontal convolution presiding over the motor element in speech. C, Laryngeal

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