medullationn.
/mɛdəˈleɪʃn/, /mᵻˌdʌlˈeɪʃn/, U.S. /məˌdəlˈeɪʃ(ə)n/ 1. Histology and Physiology. = myelination n. Cf. medulla n. 1f. Now rare.
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the world > life > biology > biological processes > procreation or reproduction > embryo or fetus > embryo development processes > [noun]
fetalization1819
segmentation1851
maceration1873
neurulation1878
blastulation1889
concrescence1890
cell lineage1892
myelination1892
spiral cleavage1892
medullation1893
myelinization1900
myelogenesis1901
induction1928
myelinogenesis1931
horizon1942
1893 Philos. Trans. 1892 (Royal Soc.) B. 183 119 This explanation receives some confirmation from what I have said above as to the variability in the medullation of the fibres of the grey rami.
1901 A. H. Buck Ref. Handbk. Med. Sci. (rev. ed.) II. 319/2 It is mainly accomplished at a time when the axones are still increasing in all dimensions, and when medullation is yet very incomplete.
1951 Proc. Royal Soc. B. 139 39 Vogt (1906) held that fibre diameter is correlated with time of medullation.
1985 Arch. Ophthalmol. 103 1833 The medullation [of nerve fibers] is an additional ophthalmic manifestation of Gorlin's syndrome.
2. Botany. The presence or development of a medulla in a stele; the condition of having such a medulla.
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1911 New Phytologist 10 254 Two rival theories..have been advanced to account for the medullation of the stele in Pteridophyta, Pteridospermæ, etc.
1942 Ann. Missouri Bot. Garden 29 249 Medullation occurs in most Lepidodendrons.
1972 Bot. Gaz. 133 286 Beginning with the primitive protostele, evolution in the fern line proceeded with medullation and the introduction of leaf gaps.
1995 Internat. Jrnl. Plant Sci. 156 888/1 Ontogenetic studies of lycopsids..have pointed to some relationships between stelar medullation and stelar diameter.
3. The presence of a medulla in a hair or feather; the nature or size of the medulla in hairs; the condition of having medullated hairs; the degree to which the hairs (of an animal, type of wool, etc.) are medullated.
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1927 Amer. Naturalist 61 546 These pigmental differences were not correlated with differences in the diameters of the hair-shafts, as was true of the differences of scalation and medullation.
1936 Philos. Trans. (Royal Soc.) B. 226 161 In filoplumes and in down feathers it [sc. the rhachis] is solid, very rarely in the latter but never in the former, having traces of medullation.
1965 Zeitschr. f. Morphol. u. Anthropol. 57 56 After properly cleaning the hair samples, 25 strands from each individual were studied for medullation.
1985 Indian Vet. Med. Jrnl. 9 7 It was found that during winter there was reduction in the number of hairs having continuous medullation and an increase in the number of hairs having discontinuous medullae.
2000 Small Ruminant Res. 38 63 Fleece fiber medullation was greatest..in summer.
This is a new entry (OED Third Edition, June 2001; most recently modified version published online March 2022).
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n.1893