Female reproductive system?

Introduction

Female is represented by ♀

Female reproductive system consist of external and internal genital organs.

External genital organs:-

Collectively known as vulva.

Internal genital organs:-

1. ovaries
2. uterine/ fallopian tubes
3. uterus
4. vagina

Gonads:-

Two in number and are known as ovaries. The ovaries produce female sex cells known as oocytes and female sex hormones known as estrogen/progesteron, inhibin and relaxin.

Uterine tube/fallopian tube/oviduct:-

These are responsible for the transportation of the oocyte and is the site of fertilization.These are the pair that convey sperms to reach an ovum and transports secondary oocytes from ovary to uterine tube.

Uterus:-

It is a hollow pear shaped muscular organ where the embryo or the fetus develop.

There are three parts of embryo:-

1. Fundus
2. Body
3. Cervix

The dome shaped upper part above the opening of the uterine tube is fundus.

Body is the main part that presents a cavity where the fetus grows.

Cervix is the lower cylindrical part that projects into the vagina.

It is the seat of implantation of fertilized ovum, growth of embryo and fetus during pregnancy and delivery of fetus at labor.

Vagina:-

It is an intromittent organ that receives penis during copulation and is the site of release of sperm. It is also the passage for child birth.

Ovaries

Ovaries are almond shaped structures. They are interaperitoneal organs and dull grey in colour.

Before puberty the surface is smooth and afterwards due to repeated ovulations the surface becomes irregular.

They are located on the either side of the uterusbelow and behind the corresponding uterine tube.

Each ovary presents two ends, two borders and two surfaces.

Ovaries produce female gametes the oocytes that develope into ova and they also produce female sex hormones the progesterone and the estrogen that are required for the maturation of gametes, receptive ueterine endometerium for implantation of fertilized ovum and growth of embryo and fetus.

Gametogenesis

The process of formation of gametes is known as gametogenesis. The gametes are derived from primordial germ cell/ primitive sex cells.

Different events in gametogenesis:-

1. formation and migration of PGC and their differentiation into male and female sex cells.
2. Mitotic division of germ cells.
3. Meiotic reduction in DNA or chromosome content of the germ cells.
4. Differentiation and maturation of germ cells.

Oogenesis

The process of maturation and differentiation of PGC to oogonia, primary oocytes, secondary oocytes and to mature ova into the female genital tract.

It’s location is ovarian cortex

Before birth:

1. Before 3rd month- The PGCs undergo mitosis to form oogonia in the absence of testicular differentiation factor(TDF).
2. Before 7th month- The oogonia continue to divide mitotically. some of the oogonia enlarge to form primary oocytes.
3. 7th month to birth- Production of million of germ cells occurs. Primary oocyte enters prophase 1 of meiosis 1 at that the meiosis is arrested by oocyte maturation inhibitor factor (OMI). The oogonia are diploid (2n) in chromosome content. Many of these oogonia and primary oocytes degenerate before birth.

Birth to puberty:

1. There will be both maturation and degeneration of primordial follicle resulting in reduction in the number of primary oocytes.
2. At the time of birth all primary oocytes are in the prophase of first meiotic division.
3. instead of entering metaphase the primary oocytes enter prolonged diplotene stage

After puberty:

1. From the time of birth to puberty there is degeneration of number of primary oocytes.
2. The first meiotic division of a primary oocyte produces two unequal daughter cells. Each daughter cell had the haploid number of chromosomes(23).
3. Ovulation takes place while the oocyte is in metaphase. The secondary oocyte remains arrested in metaphase till fertilization occurs. The second meiotic division is completed only if fertilization occurs.
4. If fertilization does not occur , the secondary fails to complete the second meiotic division and degenerates about 24 hours after ovulation.