In female baby, oogenesis starts before the birth of baby after forming primary oocyte. Further development to ovum occurs after attaining puberty.

Each primary spermatocyte undergoes first meiotic division to produce 2 secondary spermatocytes, which further proceeds to second meiotic division to form 2 spermatids. So, each primary spermatocyte produces 4 sperms.

Seminiferous tubules contain Spermatogonia and Sertoli cells. Spermatogonium undergoes meiotic division to produce sperms and Sertoli cells provide nourishment to them.

FSH (follicle stimulating hormone) stimulates Sertoli cells to secrete spermatogenic substance. Sertoli cells function as nurse cells for differentiating spermatozoa.

Girls are born with 200-300 millions of primary oocytes but all of these oocytes do not get chance to mature and change into ovum because one ovary produce only one ovum each month in the middle of menstrual cycle. So, some 500 eggs are released by female during her reproductive life.

Testosterone hormone help in release of sperm from testis. This hormone is released by leydig cells present in between seminiferous tubules of testis.

Millions of sperms are released during insemination that reaches to ovum for fertilisation. Only one sperm enter the ovum by penetrating the zona pellucida layer of ovum using the enzyme present in its acrosome.

The stoppage of menstrual cycle in human female is called menopause. This indicates the end of reproductive phase of female at the age of about 50 years.

Menstrual cycles get stopped during pregnancy. Sometimes it becomes irregular due to stress and other hormonal activities of the body.

Menstrual cycle is divided into several phase starting from menses during which endometrium breaks and comes out through vagina for 4 to 5 days. Ovulatory phase occurs in the middle of menstrual cycle (14/15th day) during which egg is released.

The inner foetal membrane invests the embryo and forms a space called amniotic cavity. It is filled with fluid called amniotic fluid. It is useful for studying chromosomal abnormalities of foetus.

After implantation of blastocysts, finger-like projections appear on the trophoblast called chronic villi which is surrounded by the uterine tissue and maternal blood.

The inner cell mass contain certain cells that contain cells called stem cells which have potency to give rise all the tissues and organs. Now a day ’s stem cells are preserved for future use.

The heart is formed first in foetus after one month of pregnancy. Limbs and digits after second months, limbs and external genital organs after three months and eye lids and hair after six months.

Oxytocin hormone is released by foetal ejection reflex from maternal pituitary gland that causes stronger and stronger uterine contraction that leads to ejection of baby through birth canal.