Question

State in brief the changes that take place in a fertilized egg(zygote) till the birth of the child in the human female reproductive system. What happens to the egg when it is not fertilized?

Answer 1

Hint: Each month, a group of eggs in tiny, fluid-filled sacs called follicles begin to develop within ovaries. Each of the eggs will finally erupt from the follicle. The follicle grows into something called the corpus luteum after the egg leaves the follicle.

Complete answer:
It fertilizes the egg if one sperm finds its way into the Fallopian tube and burrows into the egg. So that no more sperm can get in, the egg shifts. When it passes slowly across the fallopian tube to the uterus, it keeps separating.
The embryo's close attachment to the uterus is called implantation.
Fertilized egg changes:
> Zygote / Fertilized begins to break.
> Zygote implantation in the inner uterine wall.
> The embryo begins to grow with the aid of the placenta, which results in the child's growth.
> The birth of a child is a consequence of the rhythmic contraction of the uterine muscles.
> The lack of menstrual flow marks fertilization. Zygote embryonic growth soon starts in the fallopian tube and pregnancy begins. To enter the uterus, the embryo travels down and binds itself to its thickened inner wall. The embryo's close attachment to the uterus is called implantation. The embryo starts dividing. The uterus is preparing itself to feed a growing embryo. Its lining thickens to nourish developing embryos and is richly supplied with blood. If the egg is not fertilized then menstruation occurs, when the menstrual cycle starts, the egg bursts along with the living uterus, blood and mucus flow down.

Note:
The placenta is a disc lodged in the wall of the uterus. The embryo's side of the tissue includes villi. The blood spaces surrounding the villi are on the mother's side. It provides glucose and oxygen with a wide surface area to transfer from mother to embryo. Embryo production creates waste substances that can be eliminated by moving them through the placenta into the blood of the mother.