Oogenesis is the process by which oocytes are produced from primordial germ cells in females. It involves mitosis and meiosis. Primordial germ cells undergo mitosis to form primary oocytes, which then enter meiosis. During meiosis, primary oocytes become haploid secondary oocytes or polar bodies which later dissolve. Secondary oocytes may further divide into mature eggs or more polar bodies. Thus, oogenesis involves cell division and growth to form mature eggs for reproduction in females.

2.  It is the process in which oocytes are produced
from female PMGCs by mitosis and meiosis
Process.
 The initial cells in this process are called oogonial
cells, which produce primary oocytes by mitosis.
 The primary oocytes, divides meiotically into
secondary oocytes.

3.  Each primary oocytes commence nutrition and
divide meiotically to form secondary oocyte.
 These are develop into mature Ovum and also
known as egg.
 Thus, Oogenesis is the Female version of
Gametogenesis .

4. 2N2N 2N2N
2N2N2NPMGC (44+XX)
Mitosis 1st
Primary oocytesMitosis 2nd
Primary oocytes

5.  In this phase, the PMGCs(44+XX) divide
mitotically and increase in no. as
multiplicative order.
 This phase starts prior to birth of females.
 In this phase, number of chromosome
remains same while divisions occur.

6. 2N
Commencing nutrition
2N
primary Oocyteprimary Oocytes after growing.

7.  This phase starts after maturity of female.
 After primary oocyte commence nutrition, it turns
to big shape and ready for further meiotic division.

8. NNNN
N
N
2N
primary Oocyte
(after growth phase)
First polar body
polar bodiesWhich dissolves after sometime
Secondary
Oocyte
Mature
ovum (egg)
Meiosis 1st
Meiosis 2nd

9.  In this phase, Primary oocytes undergoes 1st
meiotic division and make two haploid cells in
which 1st is secondary oocyte and 2nd is polar
body.
 Secondary oocyte and polar body both divide
further and make mature egg and polar bodies
respectively.

10.  In mammals, the first part of oogenesis
starts in the germinal epithelium, which gives
rise to the development of ovarian follicles,
the functional unit of the ovary.
 The function of forming polar bodies is to
discard the extra haploid sets of
chromosomes that have resulted as a
consequence of meiosis.

11. THANK YOU..