| 释义 |
‖ medulla Biol.|mɪˈdʌlə|
[L. medulla pith, marrow, prob. cogn. w. medius middle.]
1. Anat. The marrow of bones; also, the spinal marrow. Also, † the substance of the brain.
1651Raleigh's Ghost 87 The inward medulla or marrow of the brain. 1668Phil. Trans. III. 889 He affirms, that the whole Substance called the Medulla of the Brain and the After-brain is a Heap of Fibres or Vessels. 1813J. Thomson Lect. Inflam. 393 The inner surface of the new bone..is lined with a membrane containing medulla. 1845Todd & Bowman Phys. Anat. I. 103 The cancelli are filled with fat, or medulla, the marrow of bone. 1854Jones & Siev. Pathol. Anat. (1875) 147 These tumours always arise either from the inner layer of the periosteum or from the medulla of bone. 1873–5Nicholson Zool. Glossary, Medulla. Applied to the marrow of bones; or to the spinal cord, with or without the adjective ‘spinalis’.
attrib.1904Brit. Med. Jrnl. 17 Sept. 649, I put her on red medulla tabloids.
b. (More fully medulla oblongata: lit. ‘prolonged marrow’.) The hindmost segment of the brain, or continuation of the spinal cord within the cranium.
1676Glanvill Ess. iii. 5 Those Nerves, which..are found by late Anatomists to proceed from the Medulla Oblongata. 1722Quincy Lex. Physico-Med. (ed. 2) 51 The third [process] goes backwards on the upper side of the Medulla. 1878Bartley tr. Topinard's Anthrop. 103 Section of the spinal cord where it joins the medulla oblongata. 1899Allbutt's Syst. Med. VII. 222 A softening patch on the left side of the medulla.
c. The central parts of certain organs (esp. the kidney) as distinguished from the cortex.
1878J. S. Bristowe Theory & Pract. Med. 841 The vessels—and more especially those of the medulla, the Malpigian tufts, and the stellate veins on the surface [of the kidney]—become more or less deeply congested.
d. The soft fatty substance (the ‘white substance’ of Schwann) which forms the sheath of a nerve.
1839–47Todd Cycl. Anat. III. 592/2 The real structure of the primitive nerve fibre appears to be a tube composed of homogeneous membrane, containing a delicate, soft, pulpy, semi-fluid, and transparent medulla. 1873A. Flint Physiol. Man, Nerv. Syst. i. 19 These [nerve] fibres..contain, enclosed in a tubular sheath, a soft substance called the medulla.
e. The nerve cord in certain worms.
1878Bell tr. Gegenbaur's Comp. Anat. 167 A median one [sinus]..embraces in Clepsine and Piscicola, the alimentary canal and the ventral medulla.
f. The ‘pith’ of mammalian hair. Also, the soft fibrous substance which occupies the axis of the capsule of a growing feather.
1826Prichard Researches Phys. Hist. Man. (ed. 2) I. 136 The pith or medulla [of hair] appears to be endowed with a species of vitality. 1835–6Owen in Todd's Cycl. Anat. I. 353/1 When the quill of the feather has acquired due consistence, the internal medulla becomes dried up. 1842Prichard Nat. Hist. Man. (ed. 2) 95 Weber declares the human hair to consist of a homogeneous substance, in which no distinction of cortex and medulla can be perceived.
g. The endosarc of protozoa.
1888Rolleston & Jackson Anim. Life 833 The protoplasm is either similar throughout, or it is divisible into an exoplasm (cortex) and endoplasm (medulla).
2. Bot. The pith or soft internal tissue of plants.
1651Raleigh's Ghost 96 In the Medulla or marrow of the Plant there is a genital power or vertue. 1760–72tr. Juan & Ulloa's Voy. (ed. 3) I. 286 The pod [of the guava], opened longitudinally, is found divided into several cells, each containing a certain spungy medulla. 1880Gray Struct. Bot. iii. §3. 75 The Pith or Medulla, consisting entirely of soft..thin-walled cells.
b. = medullin.
1819J. G. Children Chem. Anal. 298 Medulla was obtained by Dr. John, from the pith of the sunflower.
†3. fig. The ‘pith’ or ‘marrow’ of a subject. Often in mod.L. titles of books (cf. marrow n.1 1 d); hence used for: A compendium, abridgement, summary. Obs.
1643Milton Divorce Introd., Wks. 1851 IV. 12 Their youth run ahead into the easy creek of a System or a Medulla, sails there at will. 1660South 36 Serm. (1720) II. 17 Their preaching Tools, their Medulla's Notebooks, their Mellificiums, Concordances, and all. 1704Swift T. Tub v. Wks. 1755 I. 97 An infinite Number of Abstracts, Summaries, Compendiums,..Medullas..and the like. 1769Bush Hibernia Cur. To Rdr. 12 The abridgers, who..engage to furnish you, at a very easy expence, with the medullam of your civil history. |