1. Female reproductive physiology

2. Reproductive functions of female
Discussed under four headings
Preparation of female body for conception and gestation
Gestation itself
Labor
Lactation

3. Physiological anatomy
Main structure are
Ovaries
Fallopian tubes
Uterus
Vagina

4. Female reproductive organs

5. Female reproductive organs

6. Monthly Reproductive cycle
A single ovum is expelled from the ovaries in every cycle
The ovum then passes through fallopian tube
Preparation of endometrium for implantation
If no fertilization menstruation occurs
If fertilized, ovum passed into and implanted in the uterus
Development of fetus, placenta and fetal membranes

7. Development of primordial follicle
In fetal life ovaries covered by germinal epithelium
Primordial ova differentiate and migrate into cortex of the ovaries
Each ovum collects around it a single layer of granulosa cells from ovarian stroma
Primordial ovum surrounded by a single layer of granulosa cells called “primordial follicle”

8. Development of primordial follicle
Number of primordial follicle
At 30th week of pregnancy - 6 million
At birth only 1 million
At puberty ,000 to 400,000 only
During reproductive life
About 400 primordial follicle may ovulate
Rest of all degenerate – atresia of follicles
Depletion of Follicles → menopause

9. Primordial follicle
The granulosa cells provide nourishment for the ovum
They secrete oocyte maturation inhibitory factor (OMIF)
OMIF keep the ovum in primordial state
Suspended in the prophase of 1st meiotic division

10. The female hormonal system
Hypothalamus GnRH (LHRH)
Adenohypophysis FSH & LH
Ovaries Estrogen and Progesterone
Drastic cyclic variations in the female hormones during different phases of the monthly reproductive cycle

11. Hypothalamo hypophyseal feed back control
LH and FSH
Glycoprotein in nature
Produced by gonadotropes in adenohypophysis
LH cyclic release according to cyclic fluctuations of GnRH- exactly follows
FSH also increases or decreases with the fluctuations in GnRH- more slowly
GnRH also called as LH-releasing hormone (LHRH)
Without GnRH no secretion of LH & FSH

12. Pulsatile release of GnRH
5-25 minutes release every 2-3 hour
Corresponding pulsatile release of LH and FSH
Frequency and duration of pulse determines the level of gonadotrophic hormones
Continuous infusion of GnRH cause stoppage of production FSH and LH
So pulsatile release is necessary (reason not known)

13. Pulsatile release of GnRH

14. Female hormonal fluctuations

15. Negative feed back inhibition
Estrogen strongly inhibits Both LH and FSH
Progesterone potentiates this inhibitory effect
Both hormone also inhibit Hypothalamic GnRH
INHIBIN
Produced by granulosa cells of CL
This also has inhibitory effect on Anterior pituitary (LH, FSH) and hypothalamus (GnRH)
FSH is inhibited in direct relation with level of inhibin

16. +ve feed back for LH surge
1-2 before ovulation estrogen stimulates the secretion of LH & FSH
Reason not understood
Experimental infusion at this stage of cycle have been able to demonstrate this +ve feed back effect of estrogen
The response of hypothalamus and adenohypophysis to estrogens changes due to some unexplained reason
They are stimulated instead of normal negative feed back inhibitory response

17. Monthly reproductive cycle
Monthly rhythmic changes in the rates of secretion of different hormones and corresponding changes in the female sexual organs – called female sexual cycle
Also called menstrual cycle
Average duration = 28 days
May range between 20 – 45 days
Abnormal cycle length → ↓fertility

18. Effects of gonadotrophic hormones
Without LH & FSH no activity in the ovaries – throughout the childhood
At 10 years of age LH & FSH secretion starts
Onset of monthly sexual cycle between 11 & 16 years of life – average 13 years
Puberty
Menarche

19. Female monthly sexual cycle
Discussed under two headings
Ovarian cycle
Comprising of cyclic changes in the ovaries under the influence of FSH & LH
Endometrial cycle
Comprising of cyclic changes taking place in the endometrium under the influence of estrogen and progesterone from the ovaries

20. Ovarian cycle Follicular phase Ovulation Luteal phase
Involution of the corpus luteum

21. Ovarian cycle

22. Follicular phase FSH (& LH also) from the adenohypophysis →
Growth starts in 6-12 follicles
Growth of one follicle is more than the rest
Enlargement of the ovum
Proliferation of the granulosa cells into several layers
Surrounding stromal cells also proliferate to form several layers of theca cells
Theca interna - cellular and hormone secreting
Theca externa – vascular and fibrous forming capsule

23. Follicular phase
Primary follicle – additional layers of granulosa cells
Granulosa and theca cells secrete fluid containing hormones estrogen
Antral follicle – fluid collects to form antrum
Vesicular follicle - more growth and collection of more fluid in a single large cavity
Estrogen increases the receptors for FSH and LH (+ve feedback) → accelerated growth
Mature graffian follicle
Enlarged ovum surrounded by several layers of granulosa cells is on one pole of the follicle

24. Ovarian Cycle

25. Ovulation Occurs 14 days before the next menstruation
Protruding outer wall swells rapidly
A nipple like protrusion called ‘stigma’ develops on the surface
Fluid starts oozing out
Stigma bursts out
Viscous fluid along with ovum surrounded by several granulosa cells called corona radiata, is expelled

26. Preovulatory LH surge LH necessary for final growth and ovulation
2 days before ovulation LH level suddenly rises 6-10 folds
FSH also rises 2-3 folds
This surge causes rapid growth and onset of progesterone secretion
This will cause
Prostaglandin secretion
Hyperemia
Proteolytic enzyme secretion
More fluid formation weakening of the wall
rupture → ovulation

27. Preovulatory LH surge

28. Ovulation

29. Luteal phase
After ovulation the granulosa and theca cells change into lutein cells - luteinization
Enlargement
Filled with lipid inclusions
Develop yellow color
Well developed blood supply
The whole mass of lutein cells is called corpus luteum
Granulosa cells produce estrogen and progesterone
Theca cells produce male hormones (androgens)
Androstenedione & testosterone
Androgens are converted into female hormones by granulosa cells

30. Luteal phase
Corpus luteum grows to 1.5 cm diameter size in 7-8 days after ovulation
Estrogen and progesterone are secreted from corpus luteum
LH surge programs the follicular cells to
Proliferate
Enlarge
Secrete hormones
& then
Degenerate
HCGH causes persistent activity of Corpus Luteum in pregnancy

31. Involution of corpus luteum
Estrogen and progesterone from CL cause
Negative feed back inhibition of LH and FSH
CL also produces hormone ‘Inhibin’ which inhibits FSH secretion
Reduction or absence of LH and FSH → degeneration of CL
This is called “Involution of CL”
Involution is complete 12 days after ovulation → absence of estrogen and progesterone
This leads to new cycle of production of FSH & LH and follicular phase of new cycle

32. Key steps of regulation
Involution of CL → ↓Estrogen & progesterone
↓Estrogen & progesterone → ↑FSH (& LH)
↑FSH (& LH) → ↑ estrogen (follicular phase)
LH surge → ↑ Progesterone
Ovulation
↑ estrogen and progesterone (luteal phase)
↑ estrogen and progesterone → ↓GnRH → ↓FSH & LH
↓ FSH & LH → Involution of CL

33. Regulation of Ovarian Activity

34. The Ovarian Cycle

35. The Ovarian Cycle

36. Thank-you
Questions ??