Explain the process of fertilization, development and birth in human beings.

Fertilisation:

Fertilisation takes place when the sperm unites with the egg.

The sperms enter through the vaginal passage and travel upwards and reach the oviduct.

In the oviduct, one of the sperms fuses with the egg and the fertilisation is completed.

Development:

Fertilisation results in the formation of zygote.

The zygote divides and redivides to form a ball of cells called blastocyst.

The blastocyst gets implanted on the wall of the uterus and forms the embryo.

The embryo obtains all the nourishment and oxygen from the mother’s blood.

A structure called placenta present in the uterus supplies all the necessary nutrients to the embryo through the umbilical cord.

The development of the foetus takes place for nine months.

Birth:

When the baby is grown completely, it begins to move down towards the vaginal passage.

The opening of the cervix gradually opens, and the baby is released out through the vagina.