| blighted ovum | A fertilized ovum whose development has ceased at an early stage. (27 Sep 1997) |
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| alecithal ovum | An ovum in which the yolk is nearly absent, consisting of only a few particles. (05 Mar 2000) |
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| centrolecithal ovum | One in which the yolk is mostly located near the centre of the egg, as in arthropods. (05 Mar 2000) |
| Peters' ovum | An ovum with a presumptive fertilization age of about 13 days; for many years, it was one of very few young human embryos recovered in good condition and its study furnished many facts regarding early embryonic changes. (05 Mar 2000) |
| migration of ovum | <gynaecology> The transperitoneal passage of an ovum from the ovarian follicle into the uterine tube. (05 Mar 2000) |
| cleavage stage, ovum | The embryo in its earliest stage, lasting from the first mitotic division of the fertilised ovum into two blastomeres to the formation of the morula, a compact mass of blastomeres. (12 Dec 1998) |
| sperm-ovum interactions | Interactive processes between the ovum and the spermatozoon. (12 Dec 1998) |
| isolecithal ovum | An ovum in which the yolk is evenly distributed throughout the cytoplasm. (05 Mar 2000) |
| ovum | 1. The female reproductive cell which, after fertilization, develops into a new member of the same species (von Baer, 1827), an egg. 2. The human ovum: a round cell about 0.1 mm. In diameter, produced in the ovary, where there is deposited around it a noncellular covering (oolemma, zona pellucida, zona radiata). It consists of protoplasm which contains some yolk, enclosed by a thin cell wall (vitelline membrane). There is a large nucleus (germinal vesicle), within which is a nucleolus (germinal spot). By extension, the word is also used to designate any early stage of the conceptus, when the embryo itself constitutes a tiny and insignificant part of the whole. (18 Nov 1997) |
| ovum implantation | Endometrial implantation of the blastocyst. (12 Dec 1998) |
| ovum implantation, delayed | Delay of embryonal development whereby the blastocyst remains in the uterine cavity for a variable period of time before attaching to the endometrium and continuing its development. (12 Dec 1998) |
| ovum transport | Transport of the ovum or zygote from the site of ovulation to the site of implantation. (12 Dec 1998) |
| telolecithal ovum | An ovum in which there is a large amount of yolk massed at the vegetative pole, as in the eggs of birds and reptiles. (05 Mar 2000) |
| fertilised ovum | An ovum impregnated by a spermatozoon. (05 Mar 2000) |