| medullary tube | <embryology> The progenitor of the central nervous system. See: neural plate, neurulation. (18 Nov 1997) |
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| membranous lamina of cartilaginous auditory tube | The connective tissue membrane that, with the lateral lamina, completes the lateral and inferior walls of the cartilaginous part of the auditory tube. Synonym: lamina membranacea cartilaginis tubae auditivae, membranous layer. (05 Mar 2000) |
| chest tube thoracostomy | <procedure, surgery> A surgical procedure to create an artificial conduit into the chest cavity. Usually performed for purposes of chest drainage. (27 Sep 1997) |
| groove for auditory tube | A furrow on the inner surface of the posterior border of the greater wing of the sphenoid bone, for the cartilaginous auditory tube. Synonym: sulcus tubae auditivae, pharyngotympanic groove. (05 Mar 2000) |
| Robertshaw tube | A variation of Carlen's tube that eliminates some mechanical disadvantages of the latter. (05 Mar 2000) |
| roll tube | A modification of the plate culture; a seeded medium containing agar is placed in a test tube which is rolled or spun horizontally until the medium solidifies evenly on the interior of the tube. (05 Mar 2000) |
| roll-tube culture | A culture in a tube of medium which has been melted and allowed to solidify while the tube is being spun; the inside of the tube is thereby coated with a thin layer of solidified medium. (05 Mar 2000) |
| pharyngeal opening of auditory tube | An opening in the upper part of the nasopharynx about 1.2 cm behind the posterior extremity of the inferior concha on each side. Synonym: ostium pharyngeum tubae auditivae, pharyngeal opening of eustachian tube. (05 Mar 2000) |
| pharyngeal opening of eustachian tube | An opening in the upper part of the nasopharynx about 1.2 cm behind the posterior extremity of the inferior concha on each side. Synonym: ostium pharyngeum tubae auditivae, pharyngeal opening of eustachian tube. (05 Mar 2000) |
| pharyngotympanic tube | A tube leading from the tympanic cavity to the nasopharynx; it consists of an osseous (posterolateral) portion at the tympanic end, and a fibrocartilaginous (anteromedial) portion at the pharyngeal end; where the two portions join, in the region of the sphenopetrosal fissure, is the narrowest portion of the tube (isthmus); the auditory tube enables equalization of pressure within the tympanic cavity with ambient air pressure, referred to commonly as "popping of the ears". Synonym: tuba auditiva, tuba auditoria, eustachian tube, guttural duct, otopharyngeal tube, otosalpinx, pharyngotympanic tube, salpinx, tuba acustica, tuba eustachiana, tuba eustachii. (05 Mar 2000) |
| rotating anode tube | A modern X-ray tube, in which heat buildup is distributed through a larger volume by rotating the target. (05 Mar 2000) |
| Ruysch's tube | A minute tubular cavity opening in the lower and anterior portion of each surface of the nasal septum; best seen in the early foetal period when it is associated with the vomeronasal organ (Jacobson's organ). (05 Mar 2000) |
| Ryle's tube | A thin rubber tube, with about the lumen of a no. 8 catheter, and an olive-tipped extremity, used in the giving of a test meal. (05 Mar 2000) |
| Miller-Abbott tube | A tube with two lumens, one ending in a small collapsible balloon and the other in a metallic tip with numerous perforations; used for intestinal decompression. Synonym: Abbott's tube. (05 Mar 2000) |
| photomultiplier tube | A detector which amplifies a signal (by as much as 106) of electromagnetic radiation by an acceleration of electrons released from a photocathode through a series of dynodes; as each electron strikes a dynode stage, 3 to 4 electrons are liberated and accelerated to the subsequent dynode. (05 Mar 2000) |