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Fertilization though usually occurs within a day of ovulation, which, in turn, occurs on average 14.6 days after the beginning of the preceding menstruation (LMP). [31] There is also considerable variability in this interval, with a 95% prediction interval of the ovulation of 9 to 20 days after menstruation even for an average woman who has a ...
Human embryology is the study of this development during the first eight weeks after fertilization. The normal period of gestation (pregnancy) is about nine months or 36 weeks. The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is completed in the uterus.
Implantation bleeding occurs between 7 and 14 days after fertilization, [57] and is a small amount of light vaginal bleeding or spotting that can occur in early pregnancy due to the blastocyst penetrating the lining of the uterus during implantation.
The fertilization usually occurs in the fallopian tubes, but can happen in the uterus itself. The zygote then becomes implanted in the lining of the uterus, where it begins the processes of embryogenesis and morphogenesis .
After fertilization, the conceptus travels down the fallopian tube towards the uterus while continuing to divide [6] without actually increasing in size, in a process called cleavage. [7] After four divisions, the conceptus consists of 16 blastomeres, and it is known as the morula. [8]
In embryology, cleavage is the division of cells in the early development of the embryo, following fertilization. [1] The zygotes of many species undergo rapid cell cycles with no significant overall growth, producing a cluster of cells the same size as the original zygote.
Flowering plants (angiosperms) create embryos after the fertilization of a haploid ovule by pollen. The DNA from the ovule and pollen combine to form a diploid, single-cell zygote that will develop into an embryo. [21] The zygote, which will divide multiple times as it progresses throughout embryonic development, is one part of a seed.
Trophoblasts are present four days after fertilization in humans. [1] They provide nutrients to the embryo and develop into a large part of the placenta. [2] [3] They form during the first stage of pregnancy and are the first cells to differentiate from the fertilized egg to become extraembryonic structures that do not directly contribute to ...