OOGENESIS

 It is the process of production of eggs or ova from the germ cell which are derived from germinal epithelium of embryo .

The entire process of oogenesis divided into three phases .

1- Multiplication phase

2- Growth phase 

3- Maturation phase 

1 - Multiplication phase 

During this phase the primary germ cell divides mitotically to produce a large number of daughter cell called oogonia .

The oogonial cell contain diploid number of chromosomes  .

2 - Growth phase 

Phase of multiplication replaced by phase of growth .

Where oogonial cell is simple enlarged in size due to the absorption of nutritive material from the surrounding medium and also due to synthesis of nucleic acids and proteins .

After this changes each oogonial cell is then called the primary oocyte , having diploid number of chromosomes  .

3- Maturation phase 

During this phase the primary oocytes undergo reduction cell division .

The primary oocytes under go meosis -1 to form 2 unequal haploid daughter cell .

The large one is called as secondary oocyte and the smaller one is called first polar body .

The secondary oocytes then under goes meosis -2 to form 2 unequal haploid daughter cells. the larger one is called ovum or egg and the smaller one is called second polar body .