| 释义 |
medullary ray
medullary ray n (Botany) any of the sheets of conducting tissue that run radially through the vascular tissue of some higher plants med′ullary ray′
n. a vertical band or plate of unspecialized tissue that radiates between the pith and the bark in the stems of woody plants. [1820–30] Thesaurus| Noun | 1. |  medullary ray - a sheet of vascular tissue separating the vascular bundlesvascular rayvascular tissue - tissue that conducts water and nutrients through the plant body in higher plants |
Medullary Ray
medullary ray[me′dəl·ə·rē ‚rā] (botany) An extension of pith between vascular bundles in the plant stem. Also known as pith ray. Medullary Ray a single or polystichous layer of parenchymal cells that intersect the lignin and bast of stems and roots of dicotyledonous plants. Medullary rays serve a storage function and transport matter in a horizontal direction. medullary ray, pith ray  medullary rays In a cross section of a tree or log, one of the ribbons of tissue extending radially from the pith; may vary from microscopic to 4 in. (10 cm) or more in oak; used to store and transport food horizontally within the tree.medullary ray
ray [ra] a line emanating from a center, as a more or less distinct portion of radiant energy (light or heat), proceeding in a specific direction.α-r's high-speed helium nuclei ejected from radioactive substances; they have less penetrating power than beta rays. See also alpha particles.actinic r's light rays that produce chemical action, especially those beyond the violet end of the spectrum.alpha r's α-rays.β-r's (beta r's) electrons ejected from radioactive substances with velocities as high as 98 per cent of the velocity of light; they have more penetrating power than alpha rays but less than gamma rays. See also beta particles.cosmic r's very penetrating radiations that apparently move through interplanetary space in every direction.digital ray a digit of the hand or foot and corresponding metacarpal or metatarsal bone, regarded as a continuous unit.γ-r's (gamma r's) a type of electromagnetic radiation emitted by an atomic nucleus during a nuclear reaction; see also gamma rays.grenz r's very soft electromagnetic radiation of wavelengths of about 2 angstroms.infrared r's radiations just beyond the red end of the visible spectrum, having wavelengths of 0.75–1000 μm; see also infrared.medullary ray a cortical extension of a bundle of tubules from a pyramid" >renal pyramid.roentgen r's x-rays.ultraviolet r's radiant energy beyond the violet end of the visible spectrum, of wavelengths 0.39 to 0.18 μm; see also ultraviolet rays.x-r's see x-rays.med·ul·lar·y ray [TA] the center of the renal lobule, which has the shape of a small, steep pyramid, consisting of straight tubular parts; these may be either ascending or descending limbs of the nephronic loop or collecting tubules. Synonym(s): Ferrein pyramid, pars radiata lobuli corticalis renis, processus ferreinimed·ul·lar·y ray (med'ŭ-lar'ē rā) [TA] The center of the renal lobule, which has the shape of a small, steep pyramid, consisting of straight tubular parts; these may be either ascending or descending limbs of the nephronic loop or collecting tubules.
Synonym(s): Ferrein pyramid. medullary ray a band of PARENCHYMA cells in plant roots and stems leading out from the centre along a radius and separating the vascular tissues, forming xylem rays and phloem rays in primary and secondary growth. Rays enable the transport of water and other materials across the stem or root. see SECONDARY THICKENING.Ferrein, Antoine, French anatomist, 1693-1769. Ferrein canal - a space between the closed lids and the eyeball through which the tears flow to the punctum lacrimale. Synonym(s): rivus lacrimalisFerrein cordsFerrein foramen - the opening on the anterior aspect of the petrous part of the temporal bone which leads to the facial canal and gives passage to the greater petrosal nerve. Synonym(s): hiatus of facial canalFerrein ligament - the capsular ligament that passes obliquely down and backward across the lateral surface of temporomandibular joint. Synonym(s): lateral temporomandibular ligamentFerrein pyramid - the center of the renal lobule, which has the shape of a small, steep pyramid, consisting of straight tubular parts. Synonym(s): medullary ray; processus ferreiniFerrein tube - Synonym(s): convoluted tubule of kidneyFerrein vasa aberrantia - biliary canaliculi that are not connected with hepatic lobules.processus ferreini - Synonym(s): Ferrein pyramidmedullary ray
Related to medullary ray: renal lobuleSynonyms for medullary raynoun a sheet of vascular tissue separating the vascular bundlesSynonymsRelated Words |