a thickened band of cells present in the midline of the blastoderm in many vertebrate embryos, from which the mesodermal tissues develop.
| 单词 | θ18949 |
| 释义 | the world > life > biology > biological processes > procreation or reproduction > reproductive substances or cells > [noun] > ovum or ootid > fertilized ovum and parts (15) primitive streak1833 a thickened band of cells present in the midline of the blastoderm in many vertebrate embryos, from which the mesodermal tissues develop. mulberry mass1851 = morula, n. 2a. morule1857 = morula, n. 1 2. morula1875 Embryology. A solid cluster of cells (blastomeres) formed by the first cleavage divisions of a fertilized ovum and subsequently developing into a… stirp1875 Eugenics. (See quot. 1875.) cytula1876 In Haeckel's terminology: a fertilized ovum. vegetative pole1876 = vegetal pole n. at vegetal, adj. n.compounds. genoblast1877 The bisexual nucleus of the impregnated ovum. mulberry germ1879 = morula, n. 2a. parent kernel1879 the nucleus of a fertilized ovum. vegetal pole1881 the lower pole of an ovum or a young embryo, which divides more slowly than the upper (animal) pole and in telolecithal ova contains most of the… animal pole1882 the apex of the animal hemisphere of an ovum or blastula (cf. pole, n.2 11); contrasted with vegetal pole. amphiaster1885 Biol. A spindle-shaped formation in a developing ovum, with radiations at each end, thus resembling two star-shaped figures conjoined. oosperm1888 Chiefly Zoology. A fertilized ovum. Now rare. segmentation sphere1898 see quot. 1898. |
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