1. OVARIAN AND UTERINE CYCLES
By: Dr. Mujahid Khan

2. Female Reproductive Cycles
Starts at puberty
Normally continues until the reproductive years
Sexual or reproductive cycle involves activities of hypothalamus, pituitary gland, ovaries, uterus, uterine tubes, vagina and mammary glands

3. GnRH
Gonadotropin-releasing hormone (GnRH) is synthsized by neurosecretory cells in the hypothalamus
Carried to the anterior pituitary gland by hypophysial portal system
Stimulates the release of 2 hormones produced by this gland that act on ovaries

4. FSH
Follicle-Stimulating Hormone stimulates the development of ovarian follicles
Production of Estrogen by the follicular cells

5. LH Luteinizing Hormone serves as the trigger for ovulation
Stimulates the follicular cells and corpus luteum to produce progesterone

6. OVARIAN CYCLE
FSH and LH produce cyclic changes in ovaries called Ovarian Cycle
They cause development of follicles, ovulation and corpus luteum formation

7. Follicular Development
Growth and differentiation of primary oocyte
Proliferation of follicular cells
Formation of Zona Pellucida
Development of the Theca Folliculi

9. Theca Folliculi
Formed as the primary follicle increases in size and the adjacent connective tissue organizes into a capsule
Theca Interna: Internal, vascular and glandular
Theca Externa: A capsule like layer

10. Antrum
Is a large fluid filled cavity appears around the follicular cells of ovarian follicle
Contains follicular fluid
Ovarian follicle now called a vesicular or secondary follicle

11. Cumulus Oophorus
The primary oocyte is pushed aside of the follicle called Cumulus Oophorus
Here it is surrounded by a mound of follicular cells
It projects into the antrum

13. The follicle becomes enlarge until it gets maturity
Produces swelling on the surface of the ovary
Early development of ovarian follicle is induced by FSH
Final stages of maturation require LH

14. Estrogen Growing follicles produce estrogen
It regulates the development and functions of reproductive organs
Vascular theca interna also produces some estrogen

15. Ovulation
It occurs around mid cycle about 14 days in a 28 day menstrual cycle
Ovarian follicle undergoes sudden growth spurt under the influence of FSH & LH
Producing swelling or a bulge on Ovarian surface
An avascular spot appears on this swelling called Stigma

17. Ovulation
Cumulus Oophorus detach from interior of the distended follicle
It is triggered by a surge of LH production
It usually follows the LH peak hrs
LH Surge causes the stigma to balloon out forming a vesicle
The stigma ruptures and expel secondary oocyte with the follicular fluid

19. Ovulation
Expulsion of oocyte results from raised intrafollicular pressure
The expelled secondary oocyte is surrounded by Zona Pellucida and layers of follicular cells called Corona Radiata
Zona Pellucida is composed of 3 glycoproteins ZPA, ZPB & ZPC

21. Corpus Luteum
After ovulation the walls of the ovarian follicle and theca folliculi collapse and thrown into folds called Corpus
Luteum

22. Corpus Luteum It secretes Progesterone and some estrogen
These hormones stimulate endometrial glands to secrete and prepare endometrium for implantation of fertilized Ovum (Blastocyst)
If the oocyte is fertilized the CL enlarges
If the oocyte is not fertilized the CL involutes and degenerates in days

23. Uterine or Menstrual Cycle
It is the period during which the oocyte matures, is ovulated and enters the uterine tube
Cyclic changes in the endometrium caused by estrogen and progesterone
These changes occur in the internal layer of the Uterus

25. Menstrual Cycle Average menstrual cycle is 28 days
Day 1 is the day when menstrual flow begins
It vary in length by several days in normal women
Ranges between 23 and 35 days in 90% of women

26. Phases of Menstrual Cycle
Menstrual Phase
Proliferative Phase
Luteal Phase
Ischemic Phase

28. Menstrual Phase Starts with 1st day of menstrual cycle
Lasts for 4-5 days
Functional layer of uterine wall is sloughed off and discarded with the menstrual flow
Blood discharge from vagina is combined with small pieces of endometrial tissue

30. Proliferative Phase Is a phase of repair and proliferation
Lasts for 9 days
Coincides with growth of ovarian follicle
Controlled by estrogen secreted by follicles
2-3 fold increase in thickness of endometrium
The glands increase in number and length and the spiral arteries elongate

31. Luteal Phase Is a secretory or progesterone phase
Lasting about 13 days
Coincides with formation, functioning and growth of corpus luteum
Glandular epithelium secrete glycogen rich material
Endometrium thickens under the influence of estrogen and progesterone

32. Luteal Phase Spiral arteries grow into the superficial layer
Arteries become increasingly coiled
Large venous network develops
Direct arterio-venous anastomoses are the prominent features

34. If Fertilization Occurs
Fertilized ovum implants in endometrium on about 6th day of this phase
HCG hormone secreted by syncytiotrophoblast keeps the corpus luteum secreting estrogen and progesterone
The luteal phase continues and menstruation does not occur

35. If Fertilization Doesn’t Occur
No HCG
Corpus luteum degenerates
Estrogen and progesterone levels fall
Secretory endometrium enters an ischemic phase
Menstruation occurs

36. Ischemic Phase Decreased levels of estrogen & progesterone
Stoppage of glandular secretion
Loss of interstitial fluid
Marked shrinking of endometrium
Spiral arteries become constricted
Venous stasis & Ischemic necrosis
Rupture of damaged vessel wall
Blood seeps into the surrounding connective tissues

37. Ischemic Phase
Pools of blood form and break through the endometrial surface
Resulting in bleeding in uterine lumen and from the vagina
Loss of ml of blood
Entire compact layer and most of the spongy layer of endometrium is discarded

38. Pregnancy Phase
If pregnancy occurs, endometrium passes into the pregnancy phase
Menstruation cycle resumes 6-10 weeks after the termination of pregnancy
Menopause usually occurs between the ages of 48-55
Termination of reproductive period causes psychic changes called Climacteric

39. Anovulation Some women do not ovulate
Inadequate release of gonadotropins (FSH & LH)
Ovulation can be induced by clomiphene citrate
This stimulates pituitary to secrete gonadotropins
Causes multiple ovulation
Multiple pregnancies
Spontaneous abortions