For example, on common, origin-focused views about the essence of a human being, the fact that one developed from a particular sperm and ovum is a necessary feature of one.
Mating occurs in spring, and implantation of the fertilized ovum is delayed.
In ovarian pregnancy, the ovum is fertilized before its discharge from the follicle, resulting in the ovum's implantation in or on the ovary.
The vast majority of surrogates today are gestational (without a biological relationship to the child) rather than traditional (surrogate's own ovum is used, as with Ms. Baker).
In his researches, Lillie found that the animal ovum is coated with a gelatinous substance composed of carbohydrate and protein, which he termed fertilizin.
At the age of twenty-one, after three years of study at wartime Cambridge, she confessed to a cousin that she had never been kissed and did not know how the human ovum was fertilized.
The drug does not reliably terminate pregnancies beyond the early weeks, and it is not prescribed for an ectopic pregnancy (when a fertilized ovum is implanted outside the uterus for instance, in one of the fallopian tubes).
The zona pellucida (ZP) enclosing the mammalian ovum is important for its protection and for initial stages of fertilization, but the role of the ZP during embryo development is less clear.
In zoology, the Latin term for egg, ovum, is frequently used to refer to the single cell, while the word egg may be applied to the entire specialized structure or capsule that consists of the ovum, its various protective membranes, and any accompanying nutritive materials.
April 21 , 1849Friedberg, Germany October 25, 1922 Berlin, Germany Oskar Hertwig, (born April 21 , 1849 Friedberg, Hessen died October 25, 1922, Berlin), German embryologist and cytologist who was the first to recognize that the fusion of the nuclei of the sperm and ovum was the essential event in fertilization.
