The female reproductive cycle PART 8

The female reproductive cycle PART 8

1. T HE FEMALE REPRODUCTIVE CYCLE Ms.Anu Sebastian: B.Pharm ; M.Pharm Assistant Professor, Dept. Of Pharmacology Nirmala College Of Pharmacy Muvattupuzha,Ernakulam,Kerala

2. The female reproductive cycle includes ovarian cycle, uterine cycles,hormonal changes regulating these cycles & the cyclical changes in the breast and cervix. Ovarian cycle : It is a series of events in the ovaries that occur during & after the maturation of an oocyte . Uterine cycle : In association with ovarian cycle the concurrent series of changes in the endometrium of the uterus to prepare it for the arrival of a fertilized ovum that will develop there until birth

3. Phases of Female Reproductive cycle The duration of female reproductive cycle ranges from 24-35 days with an average duration of 28 days. Phases of cycle are: Menstrual phase Pre- ovulatory phase Ovulation Post ovulatory phase

4. Menstrual phase/Menstruation/Menses It last for first 5 days of the cycle. Events in the ovary At 25 th day onwards about 20 numbers of secondary follicles begin to enlarge. Follicular fluid from granulosa cells & fluid filtered from theca folliculi capillaries accumulate in the antrum . Events in the uterus The progesterone level declines stimulate PGs PGs cause contraction of arteriole Decreased blood supply to S.functionalis cells die Shedding of this layer. The menstrual flow (50-150ml) begins. It includes blood,tissue fluid,mucus,epithelial cells shed from the endometrium .

5. Preovulatory phase/Proliferative P hase/Uterine Phase It is the time between end of menstruation & ovulation. The length of this phase may vary.Usually in a 28 day cycle it lasts for 6-13 days. Events in the ovary 20 secondary follicles continue to grow-start secreting estrogen & inhibin . 12 th day onwards progesterone release begins. One among the 20 follicles in either one of the ovary become dominant follicle. The dominant follicle(Estrogen & inhibin )inhibit the release of FSH –less developed follicles undergo atresia .

6. Dominant follicle matures to graafian follicle. The antrum in the graafian follicle enlarges & graafian follicle becomes ready to rupture. Due to the high LH release-estrogen release by graafian follicle increases. Events in the uterus Growing follicle release estrogen stimulate mitosis in S. basalis Formation of a new S.functionalis Thickening of endometrium . Development of blood vessels & endometrial glands

7. Ovulation It takes place on the 14 th day of cycle. It is the release of secondary oocyte into the pelvic cavity. The development & maturation of secondary oocyte takes place about 20days. The secondary oocyte (in meosis -II)+ Zona pellucida + corona radiata is released. The high estrogen increase GnRH release Increase the release of LH & FSH In addition to that estrogen directly stimulate ant.pituitory to release LH all these leads to LH surge rupturing of mature graafian follicle release of secondary oocyte taken up into fallopian tube. As a result of follicle rupturing ,pain 7 little blood loss.

8. Post Ovulatory Phase It is the time between ovulation & next menstruation phase.It lasts 15-28 days of the cycle. Events in Ovary( Luteal Phase) After ovulation the basement membrane between theca cells & granulosa breaks collapse of follicle+ due to small bleeding blood clot formation corpus luteum is formed by the influence of LH. C.luteum starts secreting estrogen,progesterone,Relaxin & inhibin If the ovum is not fertilized the C.luteum continues its secretions for 2 weeks, then degenerates into Corpus albicans GnRH,FSH increases new ovarian cycle begins.

9. If fertilization occurs , the C.luteum does not undergo degeneration after 2 weeks. 8 th day after fertilization the chorion of the embryo release hCG . hCG stimulate the release of hormones from C.luteum . Events in Uterus( secretory Phase) The secretion of C.luteum stimulate the growth & coiling of endometrial gland,arterioles . Vascularization increases,endometrial thickening If no fertilization, after 2 weeks decline in progesterone level due to degeneration of C.luteum Menstruation

10. Fig: Phases of Reproductive cycle

11. THANK YOU