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Ch 27 The Reproductive System (Part 2 Final)

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  • What happens to primary oocytes during oogenesis from puberty to menopause?
    One or more primary oocytes complete the first meiotic division to produce two haploid cells: a smaller polar body that usually degenerates and a larger secondary oocyte with most cytoplasm.
  • What is the fate of the secondary oocyte if fertilization occurs?
    The secondary oocyte completes the second meiotic division, forming a second polar body and a mature ovum.
  • What is a vesicular (tertiary) follicle?
    A mature follicle containing a secondary oocyte arrested in metaphase II, characterized by a large fluid-filled cavity called the antrum.
  • What triggers ovulation in the ovarian cycle?
    A peak in estrogen levels causes the vesicular follicle to rupture, releasing the secondary oocyte.
  • What structure forms from the ruptured follicle after ovulation?
    The corpus luteum, a hormone-secreting structure that produces progesterone and estrogen.
  • What happens to the corpus luteum if fertilization does not occur?
    It degrades into scar tissue called the corpus albicans and stops hormone secretion.
  • What are primordial follicles?
    The first follicles formed before birth, each containing one primary oocyte surrounded by a single layer of squamous follicular cells.
  • How do primary follicles differ from primordial follicles?
    Primary follicles have cuboidal granulosa cells instead of squamous cells and thecal cells appear, which secrete androgens in response to LH.
  • What occurs during the secondary follicle stage?
    The follicle wall thickens, granulosa cells secrete follicular fluid, convert androgens to estrogen, and the zona pellucida becomes more visible.
  • Describe the follicular phase of the ovarian cycle.
    From day 1 to 14, cohorts of vesicular follicles grow due to FSH; one becomes dominant and the primary oocyte completes meiosis I to become a secondary oocyte.
  • What hormonal event triggers ovulation?
    A surge in luteinizing hormone (LH) around day 14 triggers the vesicular follicle to rupture and release the secondary oocyte.
  • What is the luteal phase of the ovarian cycle?
    From day 14 to 28, the ruptured follicle becomes the corpus luteum, secreting progesterone and estrogen to prepare for possible pregnancy.
  • How does the hypothalamic-pituitary-gonadal (HPG) axis regulate the ovarian cycle?
    GnRH from hypothalamus stimulates LH and FSH release from anterior pituitary, which act on ovaries to promote follicle development and hormone secretion.
  • What role does FSH play in follicle development?
    FSH stimulates granulosa cells to convert androgens into estrogens and secrete inhibin.
  • What is the effect of the LH surge on the ovarian cycle?
    It triggers ovulation and stimulates the corpus luteum to produce progesterone, estrogens, and inhibin.
  • How do estrogen and inhibin regulate the ovarian cycle after ovulation?
    They exert negative feedback on the hypothalamus and anterior pituitary to inhibit GnRH, LH, and FSH secretion, preventing premature follicle development.
  • What are the three phases of the uterine (menstrual) cycle?
    Menstrual phase (0-4 days), proliferative phase (5-14 days), and secretory phase (15-28 days).
  • What occurs during the menstrual phase of the uterine cycle?
    The stratum functionalis of the endometrium is shed, causing bleeding for 3-5 days.
  • What happens during the proliferative phase of the uterine cycle?
    The stratum functionalis regenerates under the influence of rising estrogen levels.
  • What is the secretory phase of the uterine cycle?
    The endometrium is prepared for implantation by progesterone from the corpus luteum.
  • What is endometriosis?
    Growth of endometrial tissue outside the uterus, causing irritation and scar tissue, often due to retrograde menstruation.
  • What female secondary sex characteristics are stimulated by estrogen and progesterone?
    Maturation of sex organs, breast development, fat accumulation around hips and thighs, and increased bone density.
  • What is menopause and when does it typically occur?
    Cessation of the menstrual cycle, usually between ages 46-55, due to decreased follicle number and hormone production.
  • What are common symptoms and effects of menopause?
    Reproductive organ atrophy, bone mass decline, hot flashes, and failure of negative feedback on LH and FSH.
  • What is the 'grandmother hypothesis' related to menopause?
    It suggests menopause evolved to allow older women to focus on rearing existing offspring rather than producing new children.
  • How do the autonomic nervous system divisions contribute to female sexual arousal?
    Parasympathetic activity causes vaginal secretions; sympathetic activity causes orgasm.