The document summarizes key aspects of the female reproductive system, including the ovaries, oviducts, uterus, and vagina. It describes the structure and functions of the ovaries, including oogenesis and folliculogenesis. It explains how follicles develop from primordial to tertiary stages and the roles of hormones like FSH, LH, and estrogens in follicle development and ovulation. After ovulation, it describes corpus luteum formation and the roles of the corpus luteum in pregnancy or menstruation. It also briefly discusses atresia, the degeneration of ovarian follicles.

1. Female Reproductive System I

2. Female reproductive system
 Ovaries
 Oviducts
 Uterus
 Vagina
 External genitalia

3. Ovary (female sex gland, female gonad)
 Functions
- female gamete production – ovogenesis
- female sex hormone secretion
⇓
estrogens
progesterone

4. Ovary is almond-shaped organ
 is enclosed by the tunica albuginea
 is covered with the germinal epithelium
⇓

5. Ovary is subdivided into the cortex and medulla
 Cortex
⇓
- developing ovarian follicles
- atretic follicles and atretic bodies
- corpus luteum and corpus albicans
 Medulla
⇓
- loose connective tissue
- blood vessels and lymphatics
- nerves

6. Ovarian cortex contains ovarian follicles
 Ovarian follicles include developing female germ cells

7. Ovogenesis is a process of the ovum development
 Includes 3 stages
- stage of proliferation
- stage of growth
- stage of maturation

8. Ovogenesis stage of proliferation
 is represented by oogonia (2n, 2c) proliferating by mitotic divisions
⇑
oogonia in the embryonic ovary

9. Oogonium proliferation occurs only in the fetal period
 oogonia are converted to the primary oocytes before birth
⇔

10. Ovogenesis stage of growth
 is represented by primary oocytes (2n, 4c)
 is subdivided into
- small growth
- large growth

11. Small growth begins in the embryogenesis
 primary oocytes enter the prophase
of the first meiotic division
 prophase does not complete until puberty
 oocytes remain in suspended prophase
called the dictyotene for several years

12. Large growth begins at puberty
 lasts for two weeks until before ovulation
 oocytes considerably enlarge in size
⇓
from 30µm to 150 µm
 oocytes synthesize and accumulate
⇓
- organelles
- cortical granules
- yolk granules
⇒

13. Large growth is accompanied by folliculogenesis
⇒
⇒

14. 0vogenesis stage of maturation includes meiosis
 primary oocyte (2n, 4c)
⇓
1st
meiotic division
⇓
 secondary oocyte (n, 2c)
⇓
2nd
meiotic division
⇓
 ootida (n, c)

15. First meiotic division completes before ovulation
 second meiotic division
⇓
- begins at ovulation
- is arrested at metaphase
- is completed in fertilization

16. Female meiotic division is unequal
 only one cell receives almost all the cytoplasm
 polar bodies receive minimal cytoplasm and are nonfunctional cells

17. Ovarian follicle
 is the oocyte surrounded by envelopes
 provides the microenvironment for developing oocyte

18. Folliculogenesis
 Includes stages
⇓
- primordial follicle
- primary follicle
- secondary follicle
- tertiary follicle

19. Primordial follicle
 Consists of
- primary oocyte in the small growth
- a single layer of flat follicular cells

20. Primordial follicle primary oocyte
 is arrested in the meiotic dictyotene
 measures about 30 µm in diameter

21. Primordial follicles predominate in the ovary
 are located in the cortex periphery just beneath the tunica albuginea
⇒

22. Primary follicle
 Consists of
- primary oocyte
- zona pellucida
- a single layer of cuboidal follicular cells

23. Primary follicle oocyte
 Primary oocyte
- enters the large growth
- becomes 50 to 80 µm in diameter
⇔

24. Zona pellucida
 is homogeneous acidophilic gel-like layer
 consists of glycosaminoglycans and glycoproteins
 is secreted by oocyte and follicular cells
⇔

25. Secondary (growing) follicle
 Consists of
- primary oocyte in the large growth
- zona pellucida
- several layers of follicular cells
- connective tissue theca folliculi
⇔

26. Membrana granulosa or stratum granulosum
 is stratified follicular epithelium
 follicular cells are identified as the granulosa cells

27. Stratum granulosum results from cell proliferation
estrogens stimulate granulosa cell proliferation
⇒

28. Follicular fluid or liquor folliculi
 appears when the stratum granulosum reaches
a thickness of 6 to 12-cell layers
 is secreted by the granulosa cells
FSH stimulates fluid secretion

29. Secondary antral follicles
 fluid-containing cavities coalesce forming the antrum
⇔

30. Granulosa cell endocrine function
 Granulosa cells
- convert androgens to estrogens under
FSH stimulation
- release estrogens to fluid and blood

31. Theca folliculi
 Is subdivided into
- theca interna – loose connective tissue
- theca externa – more dense connective tissue

32. Theca interna
 Contains
- rich network of small vessels
- theca cells
⇔
⇑
theca cells arise from mesenchyme

33. Theca cells are typically steroid-producing cells
 Are rich in
- sER
- Golgi apparatus
- vesicular mitochondria
- lipid droplets
⇒
LH
stimulates cell activity

34. Theca cells produce androgens under LH stimulation
 Androgens
are transported to the stratum granulosum
 Granulosa cells
- convert androgens into estrogens
- release estrogens into the fluid and blood
⇑
⇑

35. Growing follicles are estrogen-producing structures
 Estrogen blood level ⇒
- increases as the follicles grow
- attains the maximal size before ovulation

36. Hormonal regulation of ovarian follicle endocrine function
 LH stimulates the theca cells
- to produce androgens
 FSH stimulates the granulosa cells
- to convert androgens to estrogens
- to release estrogens into the blood
 Estrogens through feed-back loop
- inhibit FSH release
- activate LH production

37. Tertiary follicle (mature follicle or Graafian vesicle)
 represents the final stage of folliculogenesis
 is preovulatory follicle
 measures 10 mm and more in diameter
 extends through the full cortex thickness
 bulges on the ovarian surface

38. Tertiary follicle oocyte
 reaches its final size – about 150 µm in diameter
 resumes the first meiotic division
 becomes secondary oocyte

39. Tertiary follicle oocyte is acentrically positioned
 on the cumulus oophorus
 is surrounded by envelopes
- zona pellucida
- corona radiata
cumulus oophorus ⇑

40. Tertiary follicle envelopes
 Stratum granulosum
- becomes thin
- forms the cumulus oophorus
 Antrum
- increases in size
 Theca folliculi
- is more prominent

41. Ovulation
 is the release of the secondary oocyte
with zona pellucida and corona radiata
from the Graafian follicle ⇒
 occurs on the 14th
day of the large growth

42. Ovulating oocyte
 begins the second meiotic division
 progresses only to the metaphase
 division is arrested at the metaphase II
 secondary oocyte at the metaphase II
leaves the ovary in ovulation ⇒

43. Stigma formation
 Stigma ruptures, forming a small gap in
- germinal epithelium
- ovarian capsule
- wall of the Graafian follicle
⇓
secondary oocyte with envelopes leaves the ovary

44. Ovulation mechanisms
 follicular fluid increases in volume and pressure
 proteolytic enzymes
- lyse the stigma and follicular wall
- separate the oocyte-cumulus complex
 theca externa myofibroblasts contract
the oocyte leaves the ovary ⇒

45. Ovulation is hormonal-mediated process
 is induced by the gonadotropin maximal
blood concentration ⇒
⇓
LH peak (surge) – 12 hours before ovulation
FSH peak (surge) – 36 hours before ovulation

46. Ovulated oocyte enters the oviduct
 Oviduct infundibulum fimbriae
 cover the ovarian surface
 direct the oocyte into the oviduct
 prevent it to enter the peritoneal cavity

47. Corpus luteum or yellow body
 develops in the place of collapsed follicle
after ovulation

48. Bleeding from the capillaries into the follicular lumen
 leads to the corpus hemorrhagicum formation with a central clot
 connective tissue invades the former follicular cavity
⇔

49. Corpus luteum formation – luteinization
 Stages of
 vascularization and proliferation
 glandular metamorphosis
 secretion
 involution

50. Stage of vascularization and proliferation
 granulosa basement membrane is destroyed
 capillaries enter the stratum granulosum and form a rich vascular network
 granulosa cells and theca cells proliferate

51. Stage of glandular metamorphosis
 granulosa cells and theca-cells differentiate and become the lutein cells
 increase in size and accumulate
- sER
- mitochondria with vesicular cristae
- Golgi apparatus
- lipid droplets
- pigment lipochrome
 lipochrome imparts to lutein cells a yellow appearance in fresh preparation

52. Granulosa lutein cells
 are derived from the granulosa cells
 are pale and large – 30 µm in diameter
 are centrally located
⇔

53. Theca lutein cells
 are derived from the theca-cells
 are darker and smaller – 15 µm in diameter
 are peripherally located
⇔

54. Corpus luteum development
 lasts from 2 to 3 days after ovulation
 is controlled by LH

55. Stage of secretion
 Corpus luteum secretes progesterone
⇓
- prepares female organs (the endometrium, mammary glands) for pregnancy
- inhibits ovarian follicle development
 secretion is regulated by LTH (prolactin)

56. Corpus luteum types
 Corpus luteum of pregnancy
 develops if fertilization and implantation occur
 attains a size of 2 to 3 cm
 exists about 6 months
 Corpus luteum of menstruation
 develops if fertilization do not occur
 is small in size
 exists about 12 days

57. Stage of involution occurs after pregnancy or menstruation
 lutein cells die by apoptosis
 cell remnants are phagocytosed by macrophages
 connective tissue corpus albicans is formed
⇔

58. Atresia is a process of ovarian follicle degeneration
 primordial and primary follicles degenerate and disappear,
leaving no trace of their existence

59. Atresia of secondary and tertiary follicles
 results in the atretic body formation
⇒ ⇒ ⇒
⇑

60. Stratum granulosum changes appear in the first place
 granulosa is infiltrated by neutrophils and macrophages
 granulosa cells are sloughed into the antrum
 connective tissue and blood vessels invade
the granulosa and antrum

61. Oocyte degeneration occurs for the second time
 oocyte undergoes apoptosis
 zona pellucida becomes folded and is broken down
 their remnants are phagocytozed by macrophages

62. Theca-cells proliferate and differentiate
 become the atretic body cells
 produce steroid hormones, mainly estrogens
⇔
⇑
atretic body contains rich capillary network

63. Glassy membrane is a characteristic feature of the atretic bodies
 is the former granulosa basal membrane
 separates from follicular cells
 increases in thickness and becomes folded
the glassy membrane in an atretic follicle ⇒

64. The End
Thank you for attention!