| 释义 |
▪ I. myelin1, -ine|ˈmaɪəlɪn|
[a. G. myelin, f. Gr. µνελός marrow: see -in, -ine.]
1. Chem. Virchow's term for a fatty substance obtainable from various animal tissues (e.g. brain-substance, yolk of egg), and also from some vegetable tissues. Also attrib.
1867Syd. Soc. Bienn. Retrosp. 11 The peculiar substance termed by Virchow, myeline substance..appears to be derivable from protagon. 1867Jrnl. Anat. I. 359 So-called Myeline-forms (rounded and elongated bodies with double contours, resembling nerve-tubes). 1887tr. De Bary's Fungi, etc. 300 The motile formations observed in Beneke's myelin (protagon-mixtures).
2. Anat. The medullary sheath of nerve-fibres, or white substance of Schwann. Also attrib.
1873A. Flint Physiol. Man, Nervous Syst. i. 21 The medullary substance..is called by various names; as myeline, white substance of Schwann, medullary sheath. 1896Allbutt's Syst. Med. I. 176 The nerve fibres..undergo changes in the myelin sheath similar to degeneration.
Hence ˈmyelinate, ˈmyelinated adjs., (of nerve-fibres) furnished with myelin; myeliˈnation, the process of development of the medullary sheath of nerves in the embryo (Syd. Soc. Lex. 1891); myeˈlinic a., of or containing myelin; myeliniˈzation = myelination; ˈmyelinize v. trans., to furnish with myelin; ˌmyelino-neuˈritis, inflammation of the medullary sheath of nerves.
1894Lancet 3 Nov. 1037/1 In a muscular nerve trunk from one-third to one-half of the *myelinate fibres are from cells of the spinal root ganglion.
1899Allbutt's Syst. Med. VII. 75 An exceedingly small group of *myelinated fibres.
Ibid. 732 The changes in the cortex begin at a stage prior to the *myelination of the pyramidal fibres.
1900Lancet 18 Aug. 529 The order of succession in the *myelinisation of the projection centres and the association centres.
1903Contemp. Rev. Sept. 389 When the child plays it is literally organising its brain, *myelinising its mind-machine.
1876tr. Wagner's Gen. Pathol. 329 Neither protagon..nor one of its products of decomposition..arising from the action of alkalies furnish of themselves *myelinic forms.
1897Allbutt's Syst. Med. II. 979 *Myelino-neuritis such as is met with in disseminated sclerosis.
▪ II. myelin2 Min.|ˈmaɪəlɪn|
Also -ine.
[a. G. myelin (Breithaupt), ad. Gr. µυέλινος marrowy, f. µυελ-ός marrow.]
A yellowish- or reddish-white variety of kaolin; so called from its appearance.
1854Dana Min. 250 Myelin of Breithaupt (Talksteinmark) is from Rochlitz. |