| trigeminothalamic tract | General term designating projections from the spinal trigeminal and principal sensory nuclei of the trigeminal nerve to the thalamus; divided into a ventral trigeminothalamic tract (spinal trigeminal nucleus projections to the contralateral ventral posteromedial nucleus-VPM) and a dorsal trigeminothalamic tract (principal sensory nucleus projections to the ipsilateral VPM). See: trigeminal lemniscus. (05 Mar 2000) |
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| tuberoinfundibular tract | A system of fine, unmyelinated fibres apparently originating from small-celled nuclei of the tuber cinereum, especially the arcuate nucleus, and terminating in the median eminence of the infundibulum, in contact with modified ependymal cells and the capillary tufts from which the hypothalamohypophysial portal veins originate. See: hypophysis, neurosecretion. Synonym: tractus tuberoinfundibularis. (05 Mar 2000) |
| Turck's tract | Uncrossed fibres forming a small bundle in the pyramidal tract. See: pyramidal tract. Synonym: tractus corticospinalis anterior, tractus pyramidalis anterior, anterior corticospinal tract, anterior pyramidal fasciculus, direct pyramidal tract, fasciculus corticospinalis anterior, fasciculus pyramidalis anterior, Turck's bundle, Turck's column, Turck's tract. (05 Mar 2000) |
| fastigiobulbar tract | A fibre bundle originating in the fastigial nucleus (nucleus tecti) of both sides, passing out of the cerebellum in the inferior cerebellar peduncle (corpus restiforme), and distributing its fibres to the vestibular nuclei and other cell groups in the medulla oblongata. Prominent crossed fibres loop over the dorsal surface of the superior cerebellar peduncle before turning ventrally, forming the uncinate bundle of Russell. Synonym: tractus fastigiobulbaris. (05 Mar 2000) |
| upper respiratory tract | The nasopharynx, oral cavity, and throat. (09 Oct 1997) |
| Z-tract injection | A technique in which the skin and subcutaneous tissue are displaced laterally before inserting the needle intramuscularly; used to prevent leakage along the track of the needle and consequent tissue irritation. (05 Mar 2000) |
| urinary tract | The organs of the body that produce and discharge urine. These include the kidneys, ureters, bladder, and urethra. (12 Dec 1998) |
| urinary tract infection | A bacterial infection of the urethra, bladder, ureters or kidneys (part of the urinary tract). Common symptoms of a urinary tract infection include pain with urination, urinary urgency and increased frequency of urination. Acronym: UTI (15 Nov 1997) |
| urinary tract infections | Infections affecting those structures of the body which participate in the secretion and elimination of urine, i.e., the kidney, the ureters, the urinary bladder, and the urethra. (12 Dec 1998) |
| urinary tract physiology | Functions and activities of the urinary tract as a whole or of any of its parts. (12 Dec 1998) |
| uveal tract | The vascular, pigmentary, or middle coat of the eye, comprising the choroid, ciliary body, and iris. Synonym: tunica vasculosa bulbi, Haller's tunica vasculosa, tunica vasculosa oculi, uvea, uveal tract. (05 Mar 2000) |
| Flechsig's tract | A compact bundle of heavily myelinated, thick fibres at the periphery of the dorsal half of the lateral funiculus of the spinal cord, originating in the ipsilateral thoracic nucleus (column of Clarke) and ascending by way of the inferior cerebellar peduncle. Terminals end as mossy fibres in the granular layer of the cortex of the cerebellar vermis. The bundle conveys largely proprioceptive information originating from the annulospiral nerve endings surrounding muscle spindles and from Golgi tendon organs. Synonym: tractus spinocerebellaris posterior, Flechsig's tract. (05 Mar 2000) |
| lateral corticospinal tract | Those fibres of the pyramidal tract that cross to the opposite side in the pyramidal decussation and descend in the dorsal half of the lateral funiculus of the spinal cord; they are distributed throughout the length of the spinal cord to interneurons of the zona intermedia of the spinal gray matter. See: pyramidal tract. Synonym: tractus corticospinalis lateralis, tractus pyramidalis lateralis, crossed pyramidal tract, fasciculus corticospinalis lateralis, fasciculus pyramidalis lateralis, lateral corticospinal tract, lateral pyramidal fasciculus. (05 Mar 2000) |
| lateral pyramidal tract | Those fibres of the pyramidal tract that cross to the opposite side in the pyramidal decussation and descend in the dorsal half of the lateral funiculus of the spinal cord; they are distributed throughout the length of the spinal cord to interneurons of the zona intermedia of the spinal gray matter. See: pyramidal tract. Synonym: tractus corticospinalis lateralis, tractus pyramidalis lateralis, crossed pyramidal tract, fasciculus corticospinalis lateralis, fasciculus pyramidalis lateralis, lateral corticospinal tract, lateral pyramidal fasciculus. (05 Mar 2000) |
| lateral root of optic tract | The larger division of the posterior end of the optic tract that terminates in the lateral geniculate body. Synonym: radix lateralis tractus optici. (05 Mar 2000) |