STUDY GUIDE, CHAPTER 24,26,27
Chapter 24: Structure and Function of the Reproductive Systems
1. Embryonic Development of Reproductive Systems
o Male and female embryos are initially homologous.
o Components include:
▪ One pair of primary sex organs (gonads).
▪ Two pairs of ducts: mesonephric (Wolffian) and paramesonephric
(Müllerian).
▪ Both duct systems empty into the urogenital sinus.
o Differentiation:
▪ Male: Begins at 6–7 weeks with SRY gene expression → testis-
determining factor (TDF) production → testes development.
▪ Testosterone secreted by 8 weeks; testes descend by 9 months.
▪ Female: Occurs in absence of SRY expression; requires estrogen presence
and testosterone absence.
▪ Müllerian ducts form uterus, fallopian tubes, cervix, upper vagina by week
10.
2. HPG Axis and Hormone Regulation
o Anterior pituitary develops by week 4–5; FSH and LH appear by week 10.
o Vascular connection between hypothalamus and pituitary by week 12.
o GnRH secretion begins by end of pregnancy; gonadotropins suppressed until
puberty.
3. Puberty
o Girls: Onset at ~8–9 years; thelarche (breast development) is first sign.
▪ Obesity linked to earlier onset (due to leptin, estrogen, gonadotropin
changes).
o Boys: Begins around age 11; weight and BMI influence timing.
o CNS and endocrine systems stimulate HPG axis.
o Estradiol: breast, uterus, vagina maturation, fat deposition in hips.
o Testosterone: testes, scrotum, penis growth.
o Puberty complete upon first mature ovulation (girls) or ejaculation with sperm
(boys).
4. External Female Genitalia (Vulva)
o Mons pubis, labia majora/minora, clitoris, introitus, hymen, urinary meatus.
o Skene glands: secrete lubricating mucus.
o Bartholin glands: produce lubrication during sexual activity.
5. Internal Female Genitalia
o Vagina: Elastic fibromuscular canal; contains rugae, maintains acidic pH via
Lactobacillus.
o Uterus: Fundus, corpus, cervix; layers—perimetrium, myometrium,
endometrium.
o Fallopian Tubes: Infundibulum (fimbriae), ampulla (fertilization site), isthmus.
o Ovaries: Cortex (follicles), medulla; produce ova and secrete
estrogen/progesterone.
6. Ovarian Follicle Development
o Follicles mature, most undergo atresia; one dominant follicle ovulates.
, o After ovulation, follicle becomes corpus luteum:
▪ Enlarges and secretes hormones if pregnancy occurs.
▪ Degenerates if not fertilized, restarting cycle.
7. Ovarian and Menstrual Cycles
o Menarche: First menstruation.
o Menopause: Permanent cessation.
o Phases:
▪ Follicular/Proliferative: FSH stimulates follicle; estrogen builds
endometrium.
▪ Ovulation: Triggered by LH surge.
▪ Luteal/Secretory: Progesterone from corpus luteum prepares
endometrium.
▪ If no implantation: hormone drop → menses.
8. Hormonal Control
o GnRH from hypothalamus → FSH and LH from pituitary.
o FSH: follicular maturation.
o LH: ovulation, corpus luteum maintenance.
9. Cervical Mucus, Vaginal and Temperature Changes
o Mucus: Thin/watery pre-ovulation; spinnbarkeit at ovulation.
o Vaginal epithelium: Cornification post-ovulation; leukocyte invasion pre-menses.
o Body temp rises after LH surge (progesterone); drops before menstruation.
10. Breast Structure and Hormonal Influence
o 15–20 lobes separated by Cooper ligaments; ducts lead to lobules.
o Oxytocin: milk let-down; Prolactin: milk production.
o Gynecomastia: benign in newborns, adolescents, older men.
Chapter 25: Alterations of the Female Reproductive System
1. Sexual Maturation Disorders
o Delayed Puberty:
▪ No traits by 13; no menarche by 15–16.
▪ Can be physiologic (hormonal delay) or pathological (HPG disruption).
▪ Tx: Hormonal replacement.
o Precocious Puberty:
▪ Before age 8 (6 in Black, 7 in White girls).
▪ Central: GnRH-dependent.
▪ Peripheral: Hormones from non-gonadotropin sources.
▪ Tx: GnRH agonists.
2. Menstrual Disorders
o Dysmenorrhea:
▪ Primary: Prostaglandin-related pain.
▪ Secondary: Pathologic (endometriosis, fibroids).
▪ Tx: NSAIDs, exercise, acupuncture, vitamins.
o Amenorrhea: