Short notes on the process of ovulation in human females
Ovulation refers to the liberation of the ovum from the follicle. In human beings ovulation takes place in the middle of the menstrual cycle and it occurs only once in a month. Very rarely there might be two ovulations or multiples which result in the formation of twins and triplets.
In ovulation the primary follicle develops into a Graffian follicle and releases the egg in the follicle. The follicle stimulating hormone (FSH) secreted from the anterior pituitary, initiates ovulation along with several other factors including one more hormone luteinizing hormone (LH).
The primary oocyte first becomes detached from the surrounding epithelial cells and undergoes maturation. At the same time a homogenous covering of protein namely zonapellucida appears between the developing oocyte and the follicular cells. At this stage the follicle cells form a layer called granulosa around the zona pellucida.
Under the influence of hormones, a follicular fluid <s secreted by the follicular cells and the cells immediately surrounding the egg become separated and thus a large cavity – antrum is formed. During its final stage of development, the Graffian follicle migrates to the ovarian surface and produces a thin blister like elevation which ultimately bursts releasing the ovum into the abdominal cavity. The ovum now is trapped into one of the oviducts (fallopian tubes) and travels down into the tube.
After ovulation, the follicle as a whole may collapse. The slit opening through which the egg and follicular fluid passed during ovulation very soon gets filled with a mass of coagulated blood and follicular fluid. This collapsed ovarian follicle shrinks and becomes filled with yellow coloured cells to form a solid body called corpusluteum. This later secrets the hormone progesterone which helps in the development of endometrium in the uterus.
The ovum which does not get fertilised in the fallopian tube within 48 hours of ovulation will get degenerated. The corpus luteum which is meant to support the fertilized egg also degenerated and becomes corpus albicans which appears as disorganised globules. Simultaneously the hormone production necessary for pregnancy will also stop and the whole of structure is discharged during menstruation and a new cycle starts.