Reproductive System

1. Reproductive System Female

2. Female Reproductive System • Produce gametes • Protect and support the developing embryo • Nourish the newborn • Structures: • Ovaries • Uterine tubes • Uterus • Vagina

4. Support for the reproductive system

5. Ovaries • Paired organs located near the lateral wall of the pelvic cavity • Weigh about .25 oz • Contain all the oocytes that the female will ever have – 400,000 • Responsible for the production of ova and secretion of hormones

6. Ovarian Cycle and Oogenesis • On a monthly cycle the ovaries produce females gametes – oogenesis • Part of the ovarian cycle which is closely linked to the uterine (menstrual) cycle • At puberty increased levels of follicle stimulating hormone (FSH) trigger the start of the ovarian cycle

7. Stages of Oogenesis

8. Steps of Oogenesis • 1. Primordial follicles → primary follicles • Under the hormonal control of FSH. Primary follicle becomes larger and several layers of cells develop around the follicle • 2. Primary → secondary follicle. Increase in size, antrum begins to develop, thecal cells and granulosa cells appear • 3. Secondary → Mature, graafian follicle

9. Primordial and primary follicles

10. Secondary Follicle

11. Graafian Follicle

12. Mature follicle

13. Follicle Development

14. Ovulation

15. Ovulation • Release of the oocyte from the ovary • Occurs on day 14 of the ovarian cycle • Surge of luteinizing hormone (LH) causes the release • Only the oocyte is released; remainder of follicle stays in the ovary and forms the CORPUS LUTEUM (yellow body) • Temporary endocrine organ • Luteal phase begins – day 14

16. Corpus luteum • Formed under the influence of LH • Secretes primarily progesterone and some estrogen • These hormones maintain the lining of the uterus for possible fertilized egg • If the fertilized egg implants in the uterus the hormone HCG is produced which indicates pregnancy • If fertilization does not occur the corpus luteum degenerates into the corpus albicans • Luteal phase ends at day 28 and menses begins to start a new cycle

17. Corpus luteum

19. Uterine Tube • About 5 in long • Three regions • Infundibulum – closest to ovary, has numerous finger-like projections called fimbriae • Ampulla – usual site of fertilization • Isthmus • Epithelium is both ciliated and non-ciliated columnar cells

20. Uterine Tube

21. Histology of Uterine Tube

22. Uterine Tube

23. Uterus • Pear shaped organ, 3 in long, 2 in wide • Weighs 1-1.4 oz • Body • Fundus • Cervix • Uterine wall • Myometrium • Endometriium • Perimetrium

24. Uterus

25. Uterine Wall

26. Endometrium • Inner layer of uterus • Simple columnar epithelium • Divided into two zones • Basal layer – deepest layer, adjacent to myometrium. Permanent layer. • Functional layer – superficial layer of the endometrium. Grows from the basal layer under the influence of estrogen and progesterone.

27. Uterine (Menstrual) Cycle • Average length of 28 days • Consists of three phases • 1. Menses – days 1-5 • Destruction of functional zone of endometrium • 2. Proliferative – days 6-14 • Initial development of functional layer • Overlaps with period of follicle growth and estrogen secretion • 3. Secretory – days 15-28 • Progesterone secretion from corpus luteum • Increased vascularization and development of uterine glands

28. Uterine Cycle

29. Proliferative phase

30. Secretory phase

32. Vagina • Elastic, muscular tube extending from the cervix to the external genitalia • Stratified squamous epithelium • Elastic laminia propria • Thick muscularis layer

33. Vagina

34. Sexual Differentiation • Early embryo has bipotential gonadal tissue • Wolffian ducts • Müllerian ducts • Gender determination depends on the presence or absence of the SRY gene on the Y chromosome • SRY gene produces a protein that activates other fetal genes to develop testes from the bipotential gonadal tissue and the sex is male. • No SRY gene and product the sex is female • Occurs at 6 weeks of fetal development

35. Contraception • Birth control • Wide range of birth control methods • Vary in effectiveness

36. Abstinence • Refraining from sexual intercourse • Only 100% proven way NOT to become pregnant

37. Rhythm method • Avoiding sexual intercourse during the time when the woman is ovulating • Requires that the woman knows when she is ovulating • Sperm can live several days so it is best to avoid sex several days before and after ovulation • Often difficult to accurately predict ovulation • High failure rate

38. Barrier methods • 1. Condoms – male and female • 2. Diaphragms and cervical caps • Must be placed correctly • Used with spermicidal gels around the edges • 3. Spermicidal foams and gels • Chemical barrier • Should be used with a physical barrier method

39. Lactation • Nursing a baby can prevent ovulation and menstruation for several to many months • Nursing must be constant, at least 4 times a day • Frequent lactation prevents release of FSH and LH which prevents ovulation • Not very reliable because many women do not nurse constantly

40. Intrauterine devices (IUD) • T-shaped flexible plastic structures placed in the uterus • Many contain copper and some contain progestin • Can be left in place for long periods of time • Prevent both fertilization and implantation • Very effective – about 1% “failure” rate

41. Chemical methods • 1. Oral contraceptive – birth control pills • 2. Estrogen/progestin patches • 3. Implanted/injected progestins • Depo-Provera • 4. Morning-after pill • Take within 72 hours of unprotected sex to prevent ovulation or implantation • 5. Mifiprex; RU486 • Pregnancy termination