Ovarian cycle

 Ovarian Cycle

Ovarian cycle occurs in two phases;

1. Follicular phase

2. Luteal phase

Ovarian cycle repeat at intervals of 28 days, with ovulation occuring mid cycle (on day 14).

1. Follicular phase

Follicular phase is the period of follicle growth, considered from first to 14th day of cycle.

In ovaries there are several follicle at different stages of maturation.

1. Primordial follicle

Primordial follicle becomes primary follicle.

2. Primary follicle

Primary follicle becomes secondary follicles.

3. Secondary follicle

Secondary follicle turn into graafian (mature) follicle.

In ovarian phase estrogen is secreted by ovarian follicles (graafian follicle).

Ovulation

Ovulation is release of an oocyte, occurs on day 14th. Ovulation occurs when reputure follicle and expel secondary oocyte into peritoneal cavity.

When ovulation occurs, some women experience pain in lower abdomen caused by intense stretching of ovarian wall during ovulation, known as mittelschmerz (ovulation pain).

If more than one oocyte ovulated, can be result in multiple birth.

After ovulation the egg lives for 12 to 24 hours in uterine tube, at this time must be fertilised to become pregnant.

2. Luteal phase

Luteal phase started when wall of graafian follicle rupture. The ruptured follicle is then turned into corpus luteum.

Progesterone hormone is secreted by corpus luteum.

After ovulation released oocyte enters uterine tube, where it will be fertilized or discarded.

If pregnancy not occur, corpus luteum starts degenrating and reminas scar called corpus albicans.

If fertilization and implantation occur, about 7-8 days after fertilization, release of human chorionic gonadotropin (HCG) hormone.

Human chorionic gonadotropin (hCG) is a hormone that can be detected in urine and blood when pregnant.