1. The Female Reproductive System

2. Overview The female reproductive system produces only a limited number of gametes Most structures are located inside the body and are designed to provide a safe environment for fertilization and fetal development

3. 1 O vs 2 O characteristics Primary Ovary Uterus Fallopian tube vagina secondary Development of breasts Widening of hips Growth of hair Fat deposits around butt and hips

5. Function and Anatomy Ovaries (the female gonads) are located within the abdominal cavity The ovary contains specialized cells called follicles A single ovum (egg) develops within each follicle

6. The Ovum A special outer coating can only be penetrated by sperm of the same species At birth, immature ova are already present within the ovary (they are called oocytes) An unfertilized egg can only live for one day. If fertilized, it will implant within the endometrium and receive nourishment

7. Oogenesis - formation of a mature ova (egg) All follicles are produced in the ovaries during the 1 st six months of fetal development –Max. of 7 million produced –2 million left at birth –400,000 at onset on puberty –Approx. 400-500 mature ova develop and are released during the reproductive years

8. Oogenesis Follicles consist of two types of cells: –Primary oocyte (immature egg) –Granulosa cells Clusters of these cells are called primordial follicles –Granulosa provide nutrients, chemical signals, and protection for the developing follicle

9. Oogenesis 6-20 primary follicles begin to mature each month Only one follicle fully matures and is released from one ovary each month during reproductive years (ovaries generally alternate months) – This is called OVULATION oogenesis

10. Fimbria (fingerlike projections) sweep the ovum into the fallopian tube (oviduct) Remaining follicular cells change and become the corpus luteum (mass of follicle cells ) –Secretes progesterone and estrogen If ovum remains unfertilized, corpus luteum degenerates and a new cycle will begin

12. Cross Section of ovary

13. The oviduct is lined with cilia that create a current to move the ovum to the uterus The uterus is a muscular organ that holds the fetus (about the size and shape of a pear) The endometrium (lining of the uterus) is well-supplied with blood vessels The base of the uterus is a narrow opening formed by a ring of muscle - the cervix

14. The cervix connects to the vagina The vagina opens to the external reproductive organs - collectively called the vulva (labia majora, labia minora, and clitoris)

15. Ectopic Pregnancy When the fertilized ovum implants outside of the uterus (most common location is the fallopian tube, because the egg is fertilized here)

17. Tubal ligation

18. Hormonal Regulation of the Female Reproductive System At puberty, the hypothalamus secretes GnRH which triggers the AP to release LH and FSH LH and FSH cause the ovaries to produce the primary female sex hormones: estrogen and progesterone Secondary sex characteristics develop and reproductive cycle begins

19. Reproductive function follows a cyclical pattern - the menstrual cycle This makes sure that the ovum is released when the uterus is most receptive Usually 28 days long Regulated by changing hormone levels

20. 4 phases of menstrual cycle flow phase follicular phase ovulatory phase luteal phase

21. Flow Phase The shedding of the endometrium (also called menstruation) Marks the beginning of the menstrual cycle Approximately 5 days

22. Follicular Phase Follicles develop and release estrogen Ovum is maturing Days 6 - 13

23. Ovulatory Phase The ovum is released (ovulation) Day 14

24. Following ovulation, cells of the follicle develop into a yellowish, gland-like structure called the corpus luteum The corpus luteum secretes estrogen and progesterone

25. Luteal Phase Begins with the formation of the corpus luteum The uterus prepares to receive a fertilized egg Day 15 - 28

26. Summary - Phases of the Menstrual Cycle

28. Hormonal Control of the Menstrual Cycle The follicular stage begins with an increase in FSH levels The maturing follicle releases estrogen

29. Rising estrogen levels have 3 effects: inhibit release of FSH (when these levels drop, the follicular phase has ended) thickening of the endometrium stimulate release of LH, which triggers ovulation (ovulatory phase)

30. The high LH levels trigger the formation of the corpus luteum (luteal phase begins) Rising levels of estrogen and progesterone have the following effects: further thickening of endometrium uterine contractions prevented further ovulation prevented inhibit release of FSH and LH

31. The corpus luteum can not be maintained without the presence of LH - it begins to deteriorate As a result, estrogen and progesterone levels drop A drop in these ovarian hormones stimulates the menstrual cycle to begin again Uterine contractions take place (flow phase)

32. Feedback system - page 525

33. Summary - Hormonal Control

34. Many birth control pills contain estrogen and progesterone which inhibits ovulation. Also thickens cervix No egg = no pregnancy Birth Control Pills

36. Menopause The end of a women's’ reproductive years Estrogen level’s have dropped 90%

37. Hormonal Summary 1. FSH(follicle stimulating)-ant. pituitary stimulates production of the follicle (to mature egg) 2. Estrogen- secreted from follicle (in ovary) initiates female 2 o sex characteristics (puberty) causes thickening of the endometrium 3. Lutenizing(LH)- ant. pituitary stimulates ovulation stimulates formation and maintenance of the corpus luteum (ovary)

38. Progesterone Secreted by copus luteum Inhibits ovulation, uterine contractions Firms cervix Stimulates endometrium