The ovarian is the female gonads, and it has two functions: ovulation and the secretion of female hormones.
Ovulation refers to an egg and cumulus granulose cells released by a mature ovarian follicle, and travelled down the fallopian tubes towards the uterus. It will be more effectively to plan your pregnancy by understanding the process of ovulation and your particular reproductive cycle.
Development of ovarian follicular begins in the embryo during birth when the ovaries contain about 2 million eggs. Most of the eggs degenerate during childhood, and only 300,000 follicles near to puberty. The ovary cycles include follicular phase and luteal phase.
Follicular phase of ovarian cycle includes the maturation of ovarian follicles and ovulation. The maturation of ovarian follicles is divided into the following stages:
- Primordial follicle: Primordial follicles is constituted by a primary oocytes stayed in the meiotic diplotene and the granule cell layer surrounding it.
- Preantral follicle: Granulosa cells change from flat cells into columnar cells, called primary follicle. Under the influence of follicle stimulating hormone, FSH, follicular cells change from flat cells into columnar cells, and then a cell membrane of the primary oocyte appears, called the vitelline membrane. The follicular cells, begin to secrete a layer of glycoproteins, called the zona pellucida that separate them from the oocyte. The follicular cells form several layers around the oocyte by repeated mitotic divisions, which become the granulosa cells as their cytoplasm contains many granules.
- Antral follicle: The space between the zona pellucida and the vitelline membrane is called the perivitelline space. Finger-like processes extend from follicular cells across zona pellucida to interdigitate. As the follicle enlarges, small cavities containing a watery fluid, called liquor folliculi, appear between the granulosa cells. The cavities enlarge, due to more collection of fluid and unite together into a single large cavity, called the follicular antrum also called secondary follicle.
- Preovulatory follicle: Preovulatory follicle is the final stage of follicular development. The follicular fluid increased sharply, follicles volume significantly increased and break out to the ovarian surface.
The luteal phase referred to the days past ovulation, is the part of the cycle which starts at ovulation and ends the day before your next menstrual period. It is named after the corpus luteum (Latin: “yellow body”). Corpus luteum grows on the surface of the ovary where a mature egg was released at ovulation, which can produces progesterone in order to the body for pregnancy. The luteal phase must be last at least 10 days to support pregnancy. It usually lasts about 14 days and does not vary by more than a day in each person.