1. Biology 212 Anatomy & Physiology I
Female
Reproductive System

2. Human Reproductive System:
- Begins developing in 4th week of embryonic development.
Remains “sexually indifferent”
until 7th week in male
8th week in female

4. Both sexes: Gonads (ovaries & testes) remain inactive until puberty, when adenohypophysis (anterior pituitary) stimulates: production of gametes (sperm & oocytes)
secretion of gonadal hormones

5. Organs of adult female reproductive system - Midsaggital
Oviduct
Ovary
Uterus
Clitoris
Labia
Vagina

6. Organs of female reproductive system – Coronal from back
Oviductt
Uterus
Ovarian artery & vein
Ovary
Round Ligament
Broad Ligament
Mesosalpinx
Vagina
Mesometrium

7. Broad Ligament: Parasagittal section

8. Ovary:
Located within pelvis, 2 – 5 cm lateral to uterus
~3 cm x 2 cm x 1 cm
Site of oocyte development & ovulation after puberty

9. Ovary
Medulla = central region of connective tissue.
Cortex = outer region in which oocytes develop
Tunica Albuginea = dense irregular connective tissue, covered by visceral peritoneum
Vessels & nerves enter/leave ovary at Hilus

10. Maturation of an oocyte is called oogenesis
Cell with 46 chromosomes (“2n”) divides twice, unevenly, to produce one large oocyte with 23 chromosomes (“n”) and two small polar bodies.
During oogenesis, oocyte surrounded by follicle composed of follicular cells or granulosa cells

11. Oogenesis and growth of the follicle initiated and stimulated by follicle stimulating hormone (FSH) from anterior pituitary
During oogenesis, follicular cells surrounding the oocyte secrete the hormone estrogen, which stimulates the inner lining of the uterus to thicken and begin secreting mucus, getting ready for pregnancy.
This estrogen (from follicular cells) also inhibits pituitary gland from secreting any more FSH. Thus, no more follicles will be stimulated to develop until it stops.

12. The developing oocyte and its follicle: Four stages before ovulation
1. Primordial Follicles: All formed before birth – hundreds in each ovary Have not yet begun development since pituitary not secreting FSH; remain dormant until puberty Consists of primary oocyte surrounded by a single layer of flat follicular cells

13. The developing oocyte and its follicle: Four stages before ovulation
2. Primary Follicles: Develop only after puberty when stimulated by FSH; 3 to 4 enter this stage each cycle No change in primary oocyte Follicle has begun development – cells are larger & beginning to secrete estrogens

14. The developing oocyte and its follicle: Four stages before ovulation
Secondary Follicles:
1 or 2 primary follicles progress to this stage each cycle
Primary oocyte larger,
finishes first division of
meiosis to become a
secondary oocyte.
Follicle grows larger as
follicular cells divide to
form many layers;
continue to secrete
estrogens.
Spaces begin to develop in center of follicle

15. The developing oocyte and its follicle: Four stages before ovulation
4. Mature or Vesicular Follicle Most follicles which made it to “secondary” will reach this stage Follicle is very large; Many layers of cells surrounding fluid-filled center called antrum. Follicle secreting large amounts of estrogens.
Secondary oocyte
covered with thick,
clear membrane called zona pellucida;
pushed to one side in follicle and surrounded by
mass of follicular cells called cumulus oophorus

16. Rupture of follicle to release oocyte = ovulation.
Triggered when anterior pituitary gland secretes luteinizing hormone.

17. Ovulation:
Secondary oocyte, surrounded by zona pellucida and cumulus oophorus, released from surface of ovary, where it can be captured by the open end of the oviduct. The cumulus oophorus now called the corona radiata.

18. Luteinizing hormone also causes follicular cells of the now empty follicle to develop into a corpus luteum which secretes the hormone progesterone.

19. If fertilization occurs, corpus luteum remains and secretes progesterone for months.
If fertilization does not occur, corpus luteum degenerates to form corpus albicans.

20. Each cycle, only one (occasionally two, rarely three) follicles make it all the way to vesicular follicles & ovulation.
Remaining primary & secondary follicles degenerate to form atretic follicles.

21. When oocyte released from surface of the ovary during ovulation, it is picked up by the oviduct, (formerly called “Fallopian tube”), a hollow muscular tube which leads from near the uterus to the ovaries.

22. Oviduct:
Lateral End: Wide opening, or infundibulum, surrounds surface of ovary. Edge surrounded by finger-like fimbria.
Middle Part: Wide
ampulla
Medial End: Narrow isthmus leads into uterus. Cavity of oviduct is continuous with cavity of uterus

23. Layers of Oviduct:

24. By mechanisms not completely understood:
The oviduct moves the oocyte toward the uterus
The oviduct moves sperm away from the uterus
Fertilization occurs in ampulla of oviduct, forming the zygote, which goes through repeated mitotic cell divisions (“cleavage”) to form a morula, then a blastocyst, and eventually the embryo.

25. Oviduct moves this growing mass of pre-embryo cells toward uterus: takes 3 or 4 days.
Secretions from oviduct are necessary to keep sperm, oocyte, and pre-embryo alive.

26. Uterus: Narrowed inferiorly to form cervix, which projects into vagina
Anterior to rectum; Posterior & superior to bladder
Narrowed inferiorly to form cervix, which projects into vagina

27. Uterus: Three Layers
Endometrium: Lots of glands & blood vessels Myometrium: Thick layer of smooth muscle Perimetrium: Visceral peritoneum over thin layer of C.T.

28. Endometrium: Two layers
Uterus: Three Layers
Endometrium: Two layers
Basal layer:
Closer to myometrium;
Remains after menstruation;
Regrows functional layer.
Functional layer:
- Closer to cavity;
- Thickens every cycle; - Embryo implants here
during pregnancy;
Dies and falls off during menstruation

29. Two related cycles: Start at puberty, end at menopause

30. Vagina:
Thin-walled, tubular Inferior to uterus; Anterior to rectum Posterior to bladder & urethra
Receives penis and semen during sexual intercourse
Passage for delivery of fetus or menstrual flow

31. Layers of Vagina:
Mucosa: Non-keratinized statified squamous epithelium
over thin layer of loose connective tissue.
Muscularis: Smooth muscle
Adventitia: Fibro-elastic connective tissue;
Blends into surrounding connective tissue

32. External Genitalia:
Major (outer) labia Minor (inner) labia Vestibule Vaginal opening Clitoris
Note relationships with pubic hair and the openings of the urethra and the anus

33. The head, or glans, of the clitoris which is visible is only a small part of this organ.
Two shafts of erectile tissue extend backwards along the urethra and vagina.
These are the same erectile tissues located in the penis of a male, called corpora cavernosa

34. Female Reproductive System During Sexual Intercourse

35. Semen deposited in superior part of vagina, just inferior to its cervix.

36. Some sperm enter uterus through cervix; Transported into oviducts.

37. If sexual intercourse occurs near time of ovulation, fertilization may occur in ampulla of oviduct to form zygote, which will eventually develop into embryo after it enters uterus.

38. & to keep secreting progesterone
As embryo develops, it forms a placenta which begins to secrete the hormone human chorionic gonadotropin (HCG)
Placenta
HCG stimulates
corpus luteum of
ovary to stay alive
& to keep secreting progesterone

39. Last half of pregnancy: Placenta itself secretes progesterone
During pregnancy, progesterone: a) Keeps functional layer of endometrium healthy b) Inhibits contractions of myometrium
At end of pregnancy: Progesterone finally decreases; myometrium begins weak Braxton-Hicks contractions

40. Mass of Uterus:
Immediately before menstruation: 100 – 150 grams Immediately after end of menstruation: 50 – 100 grams End of pregnancy: 1,000 – 1,500 grams
At end of pregnancy:
Uterus extends from vagina inferiorly to bottom of sternum superiorly
Lies anterior to all other abdominal organs except bladder

41. (At end of pregnancy: Progesterone finally decreases; myometrium begins weak Braxton-Hicks contractions)
Mother’s pituitary gland begins secreting hormone oxytocin, which strengthens contractions of myometrium
Adrenal glands of fetus secrete prostaglandins, which strengthen contractions of myometrium
Labor begins.

42. Stages of Labor: Effacement (thinning) and dilation (widening) of cervix. Expulsion Delivery of Placenta
8-24 hrs
15-30 min
10-45 min

43. During pregnancy: Breast enlarges & grows glandular tissue
Production of milk: Stimulated by the hormone prolactin from mother’s pituitary gland
Baby’s sucking on breast stimulates mother’s pituitary to secrete oxytocin, which stimulates release of milk through ducts to surface

44. Your assignment for tonight:
Identify major labia, minor labia, clitoris,
Identify vaginal opening and urethral opening in vestibule
Identify locations of vagina, uterus, oviducts, ovaries
Identify nipple & areola of breast