| bundle of His | <cardiology, physiology> Small band of specialised cardiac muscle fibres that originates in the atrioventricular node and extends into the membranous part of the interventricular septum. (12 Dec 1998) |
|---|---|
| bundle of Rasmussen | A bundle of fibres that originates from the periolivary nuclei bilaterally, exits the brainstem on the vestibular nerve, joins the cochlear nerve in the inner ear, and terminates on outer hair cells. Synonym: bundle of Rasmussen, olivocochlear fibres. (05 Mar 2000) |
| Gantzer's accessory bundle | <anatomy> An accessory muscle extending from the superficial flexor of the digits to the deep flexor of the digits. (05 Mar 2000) |
| vascular bundle | Strand of vascular tissue in a plant, composed of xylem and phloem. (18 Nov 1997) |
| Gierke's respiratory bundle | A slender, compact fibre bundle extending longitudinally through the dorsolateral region of the medullary tegmentum, surrounded by the nucleus of the solitary tract, below the obex decussating over the central canal, and descending over some distance into the upper cervical segments of the spinal cord. It is composed of primary sensory fibres that enter with the vagus, glossopharyngeal, and facial nerves, and in part convey information from stretch receptors and chemoreceptors in the walls of the cardiovascular, respiratory, and intestinal tracts; in rostral parts of the tract impulses are generated by the receptor cells of the taste buds in the mucosa of the tongue. Its fibres are distributed to the nucleus of the solitary tract. Synonym: tractus solitarius, fasciculus rotundus, fasciculus solitarius, funiculus solitarius, Gierke's respiratory bundle, Krause's respiratory bundle, round fasciculus, solitary bundle, solitary fasciculus. (05 Mar 2000) |
| Vicq d'Azyr's bundle | A compact, thick bundle of nerve fibres that passes dorsalward from the mamillary body on either side to terminate in the anterior nucleus of the thalamus. Synonym: fasciculus mamillothalamicus, fasciculus thalamomamillaris, mamillothalamic tract, Vicq d'Azyr's bundle. (05 Mar 2000) |
| glaucomatous nerve-fibre bundle scotoma | See: caecocentral scotoma. (05 Mar 2000) |
| medial forebrain bundle | A complex group of fibres arising from the basal olfactory regions, the periamygdaloid region, and the septal nuclei, and passing to the lateral hypothalamus. Some fibres continue into the tegmentum. (12 Dec 1998) |
| medial longitudinal bundle | A longitudinal bundle of fibres extending from the upper border of the mesencephalon into the cervical segments of the spinal cord, located close to the midline and ventral to the central gray matter; it is composed largely of fibres from the vestibular nuclei ascending to the motor neurons innervating the external eye muscles (abducens, trochlear, and oculomotor nuclei), and descending to spinal cord segments innervating the musculature of the neck. Synonym: fasciculus longitudinalis medialis, Collier's tract, medial longitudinal bundle, posterior longitudinal bundle. (05 Mar 2000) |
| right crus of atrioventricular bundle | The right leg or branch of the atrioventricular bundle which diverges from the left crus just below the membranous portion of the interventricular septum to descend the septal wall of the right ventricle and ramify beneath the endocardium. Synonym: crus dextrum fasciculi atrioventricularis. (05 Mar 2000) |
| Meynert's retroflex bundle | A compact bundle of fibres arising in the habenula and passing ventralward to the interpeduncular nucleus at the base of the midbrain; part of its fibres bypass this nucleus and terminate in the raphe nuclei of the caudal mesencephalic tegmentum. Synonym: fasciculus retroflexus, habenulointerpeduncular tract, Meynert's fasciculus, Meynert's retroflex bundle. (05 Mar 2000) |
| Pick's bundle | A bundle of nerve fibres recurving rostralward from the pyramidal tract in the medulla oblongata, and believed to consist of corticonuclear fibres. (05 Mar 2000) |
| Monakow's bundle | A somatotopically organised fibre bundle, relatively small in humans, arising from the red nucleus, immediately crossing in the ventral tegmental decussation, descending near the lateral surface of the brainstem into the lateral funiculus of the spinal cord at the ventral border of the lateral pyramidal tract. It terminates in the zona intermedia of the spinal cord where its distribution coincides with that of the lateral pyramidal tract; in contrast to the latter it appears not to have direct connections with spinal motor neurons. Impulses conveyed by this tract indirectly increase flexor muscle tone. Synonym: tractus rubrospinalis, Monakow's bundle, Monakow's tract, prepyramidal tract. (05 Mar 2000) |
| comma bundle of Schultze | A compact bundle composed of descending branches of posterior root fibres located near the border between the fasciculi gracilis and cuneatus of the cervical and thoracic spinal cord; it corresponds to the septomarginal fasciculus, Hoche's tract, or oval area of Flechsig in the lumbar, and to the triangle of Philippe-Gombault in the sacral spinal segments; like these, it can be demonstrated only in cases of demyelination resulting from dorsal root lesions. Synonym: fasciculus semilunaris, fasciculus interfascicularis, comma bundle of Schultze, comma tract of Schultze, interfascicular fasciculus. (05 Mar 2000) |
| muscle bundle | A group of muscle fibres ensheathed by connective tissue (perimysium). (05 Mar 2000) |