Menstrual Cycle | Hormonal Regulation

Hormonal Regulation of Menstrual cycle ,
Outline:
~introduction
~different ovarian phases
~different uterine phases
~hormonal regulation at each phase
~general overview

1. Group D Shriyas Maharjan Hormonal Regulation of Menstrual Cycle

2. Menstrual Cycle The monthly rhythmical cycle of changes in R/O secretion of female hormones and corresponding physical changes in ovaries and other reproductive organs is called menstrual cycle. Normal duration: 28days (20-45 days)

3. Negative feedback regulation Estrogen in small amount Progesterone Inhibitory effect is multiplied in presence of both hormone Positive feedback regulation Estrogen in peak level ( LH 6 to 8 times and FSH 2 times ) Regulation of M onthly Cycle

4. Ovarian Phases Follicular or Pre- ovulatory Phase Luteal or Post- ovulatory Phase

5. Uterine Phases Bleeding Phase ( 1 st -5 th day ) Proliferative Phase ( 6 th -14 th day ) Secretory Phase (15 th -28 th day)

6. Menstrual Phase Corpus luteum degenerates Decrease in estrogen and progesterone Involution of endometrial wall. Vasoconstriction of spiral blood vessel Necrosis of outer layer of endometrium Uterine contraction in presence of PGs Menstruation

7. Proliferative Phase Follicular dev in the presence of FSH Granulosa cell of follicle secrete estrogen Increase in estrogen with growth of follicle Negative feedback (inhibition) of FSH & LH Except the largest follicle , other follicles cease to grow

8. Proliferative Phase In 12 to 13 th day estrogen reaches peak level Granulosa cell starts producing progesterone Progesterone increases slightly 1 day before ovulation Positive feedback effect on secretion of FSH and LH

9. Secretory Phase Remainder granulosa cells and theca cells undergo luteinization , and form corpus luteum Granulosa cell secret large amount of estrogen and progesterone (mainly) Theca cell produce progesterone and androgen estrogen estrogen and progesterone level

10. Secretory Phase Feedback inhibition of secretion of FSH and LH by progesterone and estrogen Inhibin secreted by luteal cell also inhibit FSH and LH 2 day before menstruation corpus luteum regress to corpus albicans Decrease in estrogen and progesterone Menstrual flow

11. Reference Guyton and Hall – Textbook of Medical Physiology ; 13 th edition A.B.S Mahapatra – Essentials of Medical Physiology; 3 rd edition

12. THANK YOU