Reproduction II

1. Flashcard

• Front: What are the main components of the female reproductive tract mentioned in the sources?

• Back: The main components are the ovaries, oviducts, uterus, cervix, and vagina.

2. Flashcard

• Front: What is the broad ligament and what are its functions?

• Back: The broad ligament is a folding of the peritoneum (mesothelium and connective tissue). Its functions include supporting (“hanging”) several anatomical components of the reproductive tract, preventing friction, and housing the vascular supply, lymphatics, and nerves.

3. Flashcard

• Front: What are the three regions of the broad ligament and what do they support?

• Back: The three regions are: 1. Mesovarium (ovaries), 2. Mesosalpinx (oviducts), and 3. Mesometrium (uterus, cervix).

4. Flashcard

• Front: Describe the anatomy and functions of the ovaries.

• Back: The ovaries are glandular organs that house the female gametes surrounded by ovarian follicles. Their anatomy includes: 1. Tunica albuginea (outer connective tissue), 2. Cortex (houses follicles and corpus luteum), and 3. Medulla (houses vasculature, lymphatics, and nerves). Their functions are: 1. Production of oocytes (oogenesis), 2. Development of ovarian follicles (folliculogenesis), and 3. Production of hormones (estradiol & progesterone).

5. Flashcard

• Front: Describe the anatomy and functions of the oviducts. What are other names for the oviducts?

• Back: The oviducts are bilateral conduits between the ovaries and uterus that transport oocytes, embryos, and spermatozoa. Their anatomy and function include: 1. Infundibulum (capture cumulus-oocyte complex), 2. Ampulla (site of fertilization), and 3. Isthmus (transport and short-term storage of sperm). Other names for the oviducts are fallopian tubes, uterine tubes, and salpinges.

6. Flashcard

• Front: Describe the anatomy and functions of the uterus.

• Back: The uterus is a hollow, pear-shaped muscular organ situated in the pelvic cavity. Its anatomy includes: 1. Endometrium, 2. Myometrium, and 3. Perimetrium. Its functions are: 1. Site of embryo implantation & growth, 2. Sperm transportation, 3. Responsive to hormones à contractions, and 4. Prostaglandin secretion à luteolysis.

7. Flashcard

• Front: Describe the anatomy and functions of the cervix.

• Back: The cervix is a muscular tunnel-like organ located at the lower, narrow end of the uterus. Its anatomy includes: 1. Endocervix (monolayer columnar epithelium), 2. Ectocervix (stratified squamous epithelium), 3. Os, and 4. Cervical folds + crypts. Its functions include: barrier for uterine protection, mucus production (non-pregnant: lubrication à facilitate sperm motility; pregnant: mucous plug à seal pregnancy).

8. Flashcard

• Front: Describe the anatomy and functions of the vagina.

• Back: The vagina is an elastic, muscular canal of 7 to 10 cm in length that serves as an entrance to the female reproductive tract. Its anatomy includes a cranial region and a caudal region. Its functions are: copulatory organ, birth canal, mucus production for lubrication, and low pH (3.8 – 4.5) à microenvironment regulation.

9. Flashcard

• Front: What is the vulva and what are its functions?

• Back: The vulva provides anatomical closure to the vagina, minimizes the entry of foreign materials, and contains the clitoris, which is highly innervated erectile tissue, homologous to the penis.

10. Flashcard

• Front: What is the menstrual cycle?

• Back: The menstrual cycle is a series of changes in hormone production & uterus structure that make pregnancy possible and is also known as the uterine cycle.

11. Flashcard

• Front: What is the ovarian cycle?

• Back: The ovarian cycle is a series of changes in the ovary including follicle maturation, ovulation & corpus luteum formation and is also known as folliculogenesis.

12. Flashcard

• Front: What are ovarian follicles and what are their functions?

• Back: Ovarian follicles are supportive structures that secrete a variety of hormones. They are made up of multiple cell types that proliferate upon stimulation from the HPG axis, protect the oocyte from the environment, provide nutrition and biochemical support, and contribute to oocyte maturation. Folliculogenesis is the follicular phase of the ovarian cycle.

13. Flashcard

• Front: Describe a primordial follicle.

• Back: A primordial follicle consists of a single layer of flat cells surrounding the oocyte and represents the ovarian reserve.

14. Flashcard

• Front: Describe a primary follicle.

• Back: A primary follicle consists of a single layer of cuboidal cells surrounding the oocyte and produces estradiol (E2).

15. Flashcard

• Front: Describe a secondary follicle.

• Back: A secondary follicle has 2 – 3 layers of cuboidal cells surrounding the oocyte and produces E2.

16. Flashcard

• Front: Describe an antral follicle. What hormones is it dependent on and what does its antrum contain?

• Back: An antral follicle has an antrum, which is a fluid-filled cavity containing E2. It is dependent on LH and FSH.

17. Flashcard

• Front: What is the corpus hemorrhagicum?

• Back: The corpus hemorrhagicum is the initial corpus structure that is bloody from ruptured blood vessels.

18. Flashcard

• Front: What is the corpus luteum and what is its main function?

• Back: The corpus luteum is a critical structure comprised of luteal cells. It secretes progesterone (P4) to maintain pregnancy.

19. Flashcard

• Front: What is the corpus albicans?

• Back: In the absence of pregnancy, the corpus luteum regresses into the corpus albicans, which is a white small structure that eventually disintegrates.

20. Flashcard

• Front: What are the structural components of an antral follicle?

• Back: The structural components of an antral follicle are: 1. Theca externa, 2. Theca interna, 3. Granulosa cells, and 4. Cumulus-oocyte complex.

21. Flashcard

• Front: What are the functions of an antral follicle?

• Back: The functions of an antral follicle are to produce estradiol (E2) which regulates ovarian and uterine cycles, and to house and protect the maturing oocyte.

22. Flashcard

• Front: Describe the theca externa.

• Back: The theca externa is the outer layer of the antral follicle, consisting of loose connective tissue that surrounds and supports the follicle.

23. Flashcard

• Front: Describe the theca interna.

• Back: The theca interna is located just beneath the theca externa, has LH receptors, and produces androgens (testosterone).

24. Flashcard

• Front: Describe the granulosa cells.

• Back: Granulosa cells are the mural granulosa cells that line the inner part of the basal lamina, have FSH receptors, and convert androgens into estradiol (E2). FSH also stimulates their growth and proliferation, production of FSH receptors, and aromatase production and activity.

25. Flashcard

• Front: What is the main hormone secreted by the corpus luteum and what cells produce it?

• Back: The main hormone secreted by the corpus luteum is progesterone (P4), which is produced by luteal cells.

26. Flashcard

• Front: What is the corpus luteum formed from after ovulation?

• Back: The corpus luteum is an endocrine gland formed by the remaining follicular cells (granulosa and theca cells) after ovulation through a process called luteinization induced by the LH surge.

27. Flashcard

• Front: What are the steps in progesterone synthesis in luteal cells?

• Back: 1. Transported using LDL and HDL. 2. Luteal cells express LH receptors. 3. Activates adenylyl cyclase. 4. Converts ATP to cAMP. 5. Activates protein kinases (enhance internalization, activates cholesterase, activates StAR protein). 6. Cholesterol converted to pregnenolone. 7. Pregnenolone converted to progesterone (P4). Progesterone is derived from cholesterol.

28. Flashcard

• Front: What are the two phases of the ovarian cycle and their predominant hormones?

• Back: The two phases are the follicular phase with the predominant hormone estradiol (E2) and the luteal phase with the predominant hormone progesterone (P4).

29. Flashcard

• Front: What are the three components of the HPG axis?

• Back: The three components of the HPG axis are the 1. Hypothalamus, 2. Pituitary gland, and 3. Gonads.

30. Flashcard

• Front: Describe the endocrine regulation of reproduction via the HPG axis.

• Back: 1. The hypothalamus secretes GnRH which acts on the pituitary gland. 2. The pituitary gland releases LH & FSH (gonadotropins) into systemic circulation. 3. LH & FSH reach the ovaries. 4. Ovarian follicle & CL cells have LH & FSH receptors. 5. The ovaries secrete E2 (follicular phase) or P4 (luteal phase). 6. Feedback mechanisms mediate the endocrine response.

31. Flashcard

• Front: What are the effects of Follicle-Stimulating Hormone (FSH) on ovarian follicles?

• Back: FSH stimulates the growth and proliferation of granulosa cells in ovarian follicles, stimulates the production of FSH receptors on GCs (leading to increased sensitivity to FSH), and stimulates aromatase production and increased enzymatic activity in the GCs which converts testosterone to estradiol (E2).

32. Flashcard

• Front: What are the effects of Luteinizing Hormone (LH) on theca interna cells and granulosa cells?

• Back: LH stimulates theca interna cells to produce testosterone. It also stimulates the production of LH receptors on outer GCs. High concentrations of LH after the LH surge weaken follicle walls, cause follicle collapse leading to ovulation, and induce the formation of the corpus luteum.

33. Flashcard

• Front: What is the role of estradiol (E2) produced by the follicles?

• Back: Estradiol (E2) stimulates the production of FSH receptors and LH receptors, which establishes the dominant follicle. Increased E2 production in the antral follicle induces positive feedback to the pituitary gland and regulates ovulation. E2 also stimulates the growth of the endometrium during the proliferative phase of the uterine cycle and stimulates spiral artery development in the endometrium during the luteal phase.

34. Flashcard

• Front: Describe the events leading to ovulation.

• Back: Increased E2 during the dominant follicle stage induces an LH surge 2 days before ovulation. The LH surge changes follicle structure, weakening follicle walls and increasing antral pressure, causing the follicle to rupture and release the cumulus-oocyte complex.

35. Flashcard

• Front: Describe the luteal phase of the ovarian cycle.

• Back: The LH surge converts the remaining granulosa and theca cells into luteal cells, a process called luteinization. Luteal cells generate progesterone (P4) and estradiol (E2), which sustain endometrium development. P4 stimulates endometrial gland secretions, while E2 stimulates spiral artery development.

36. Flashcard

• Front: What happens during menstruation?

• Back: No implantation leads to a decrease in progesterone (P4) & estradiol (E2), resulting in menstruation. Menstrual discharge consists of ~80 mL of blood, fluid, & cell debris from the upper layer of the endometrium expelled from the uterus. In primates, endometrial spiral arteries are responsible for menstrual bleeding (overt menses), while other mammals exhibit covert menses without bleeding.

37. Flashcard

• Front: What are the three phases of the uterine cycle?

• Back: The three phases of the uterine cycle are: 1. Proliferative phase, 2. Secretory phase, and 3. Menstrual phase.

38. Flashcard

• Front: Describe the proliferative phase of the uterine cycle. When does it occur and what hormone drives it?

• Back: The proliferative phase occurs during the follicular phase of the ovarian cycle. Increased estradiol (E2) stimulates the growth of the endometrium.

39. Flashcard

• Front: Describe the secretory phase of the uterine cycle. When does it occur and what hormone drives it?

• Back: The secretory phase occurs during the luteal phase of the ovarian cycle. Increased progesterone (P4) from the corpus luteum stimulates the development of uterine glands. The endometrium also grows in thickness due to E2 & P4.

40. Flashcard

• Front: Describe the menstrual phase of the uterine cycle. What causes it?

• Back: The menstrual phase involves the necrosis & sloughing of the endometrium. It is the result of a decrease in ovarian hormone secretion (E2 & P4) during the late luteal phase.

41. Flashcard

• Front: Provide examples of functional ovarian cysts.

• Back: Examples of functional ovarian cysts are follicular cysts and luteal cysts.

42. Flashcard

• Front: What are some characteristics of Polycystic Ovarian Syndrome (PCOS)?

• Back: Characteristics of PCOS include sparse, frequent, irregular menses, increased androgen production, and multiple follicular cysts in the cortex.

43. Flashcard

• Front: What are some symptoms associated with Premenstrual Syndrome (PMS)? When does it typically occur?

• Back: PMS can involve physical, mood & behaviour-related symptoms such as mood swings, anxiety & depression, difficulty concentrating, headaches, irritability, changes in appetite and libido, fatigue, bloating, breast tenderness, weight gain, back aches, cramps, joint pain, skin issues, diarrhea or constipation, and hot flashes. It has a temporal correlation with the luteal phase, requires ovulation & CL formation, and disappears with pregnancy and menopause.

44. Flashcard

• Front: How do birth control pills work?

• Back: Birth control pills containing synthetic estrogen & progesterone override the system with high concentrations of ovarian hormones, leading to negative feedback inhibition of pituitary secretions. This results in no LH surge, so ovulation never occurs, and they simulate a false luteal phase.

45. Flashcard

• Front: What happens during menopause?

• Back: At menopause, the ovaries are depleted of follicles and stop secreting estrogen (change at the ovarian level, not pituitary level). This is associated with an increased risk of osteoporosis, hot flashes, & aging. A weak form of estrogen (estriol) is made in adipose tissue, so females with more adipose tissue may have higher levels of estrogen and a lower risk of osteoporosis.

46. Flashcard

• Front: What is oogenesis?

• Back: Oogenesis is a discontinuous process for the development of an ovum into a cell competent to further develop into an embryo when fertilized. It involves the formation and genotypic maturation of the female gametes, begins during embryonic development, continues throughout reproductive life, and results in an ovum that sustains embryonic development.

47. Flashcard

• Front: What is folliculogenesis? How does it differ from oogenesis?

• Back: Folliculogenesis is a continuous process occurring cyclically for primordial follicle recruitment to large antral follicle formation and ovulation. Unlike the discontinuous process of oogenesis, folliculogenesis is a continuous cyclical process involving the development of the ovarian follicles.

48. Flashcard

• Front: Describe the structure and function of the corona radiata.

• Back: The corona radiata consists of cumulus granulosa cells surrounding the oocyte. It has intensive crosstalk with the oocyte to coordinate oocyte development, mediated by gap junctions. The combination of the corona radiata and oocyte is known as the cumulus oocyte complex (COC).

49. Flashcard

• Front: Describe the structure and function of the zona pellucida.

• Back: The zona pellucida is a protective membrane that covers and protects the entire oocyte and facilitates sperm binding. ZP proteins are important for fertilization.

50. Flashcard

• Front: What are cortical granules and what is their function?

• Back: Cortical granules contain enzymes that prevent polyspermy (multiple sperm fertilizing the egg).

51. Flashcard

• Front: What is the role of the oocyte's cytoplasm (vitellus or yolk)? Why is asymmetric cell division important in oogenesis?

• Back: The cytoplasm provides nourishment to the embryo. Asymmetric cell division ensures that cytoplasm is conserved in the developing oocyte and that only genetic material is extruded with polar bodies. This sustains early embryonic development until implantation into the uterus. Mammalian eggs are small because they establish a placental connection to the mother and do not need to store large amounts of yolk.

52. Flashcard

• Front: What are the three stages of oogenesis?

• Back: The three stages of oogenesis are: 1. Oocytogenesis, 2. Ootidogenesis, and 3. Oogenesis.

53. Flashcard

• Front: Describe oocytogenesis. When does it occur?

• Back: Oocytogenesis involves mitotic divisions of oogonia, resulting in more oogonia. It occurs during embryonic development. Mitotic divisions determine the size of the ovarian reserve. Oogonia differentiate into primary oocytes.

54. Flashcard

• Front: Describe ootidogenesis. What are its two phases and what characterizes them?

• Back: Ootidogenesis involves the first meiotic division of a primary oocyte, resulting in a secondary oocyte and a polar body. It occurs after puberty, cyclically. The embryonic phase is characterized by the onset of meiosis I and nuclear arrest of primary oocytes in the diplotene stage of Prophase I, forming a germinal vesicle (GV). All primary oocytes are arrested in Prophase I at birth to protect DNA. The adult phase is characterized by the resumption of meiosis I, resulting in a secondary oocyte.

55. Flashcard

• Front: What happens to the oocyte at the onset of puberty regarding the zona pellucida and gap junctions?

• Back: At the onset of puberty, the zona pellucida forms, covering and protecting the oocyte. Gap junctions form, allowing cytoplasmic communication across the zona pellucida, which is critical for communication between the oocyte and granulosa cells (GC). The oocytes also undergo substantial growth of cytoplasm volume and cytoplasmic maturation.

56. Flashcard

• Front: What triggers the resumption of meiosis I in the oocyte during adulthood? What cellular changes facilitate this?

• Back: The LH surge triggers the resumption of meiosis I. High LH concentrations stimulate LH receptors on mural GCs, leading to the deterioration of gap junctions. This reduction in oocyte cAMP leads to the deactivation of kinases and the activation of MPF (Maturation-Promoting Factor). Loss of gap junctions is essential for meiosis resumption.

57. Flashcard

• Front: Describe the events of meiosis I during ootidogenesis. What is the outcome?

• Back: Meiosis I involves crossing-over, where segments of one chromosome cross over to a homologous chromosome, ensuring genetic diversity. It concludes with the completion of meiosis I, which is an asymmetric cytoplasmic division resulting in the extrusion of the first polar body and a unique secondary oocyte.

58. Flashcard

• Front: What is the state of the secondary oocyte at ovulation?

• Back: At ovulation, the secondary oocyte is arrested at the metaphase II stage of meiosis.

59. Flashcard

• Front: Describe the final stage of oogenesis. When does it occur?

• Back: The final stage of oogenesis involves the completion of the second meiotic division, resulting in a mature ovum and two polar bodies. This occurs only after fertilization in mammals. The secondary oocyte resumes and completes meiosis II upon fertilization.