Female Genital & Reproductive System – Comprehensive Exam Notes

Gross & Microscopic Anatomy

• Major regions mentioned → Ovaries, Uterine (Fallopian) tubes, Uterus, Cervix, Vagina, Vulva
• Ovaries (female gonads)
– Dual function: produce egg cells (ova) + sex hormones (estrogens, progesterone, inhibin, small androgen output)
– Internal design
• Medulla – central core w/ major blood vessels & nerves
• Cortex – peripheral zone housing ovarian follicles
– Each follicle = single immature egg + surrounding supporting (granulosa + thecal) cells in fluid-filled cavity
– Ovulation = monthly “bursting” of mature (Graafian) follicle → release of secondary oocyte into peritoneal cavity

• Accessory Duct System
– Uterine/Fallopian tubes (a.k.a. oviducts)
• 4 named portions:
▸ Infundibulum – trumpet-shaped, ovarian end
▸ Fimbriae – fingerlike projections sweeping the ovary
▸ Ampulla – middle, longest segment & primary site of fertilization
▸ Isthmus – narrow medial segment joining uterus
• Wall = smooth muscle + ciliated columnar epithelium → peristalsis + ciliary beating propel oocyte/zygote
– Uterus
• Orientation: typically anteverted (tilts forward over bladder)
• Portions: Fundus (dome), Body/Corpus, Cervix (narrow outlet)
• Wall layers
▸ Perimetrium – serous outer coat
▸ Myometrium – thick smooth‐muscle layer (labor contractions)
▸ Endometrium – mucosa w/ 2 strata
– Stratum functionalis (shed during menses ≈ q 2828 days)
– Stratum basalis (regenerates new functionalis; insensitive to ovarian hormones)
▸ Spiral arteries in lamina propria undergo spasm → functional layer sloughs
– Vagina
• Distensible fibromuscular tube ("birth canal")
• Functions → menstrual flow outlet, copulatory organ, passage for neonate
• No intrinsic glands; lubrication via cervical mucus + transudation (“vaginal sweating”)

• External Genitalia (Vulva)
– Clitoris = erectile structure, richest sensory innervation → sexual pleasure center
– Vaginal orifice – shared passage for neonate, menses, semen
– Urethral orifice – external exit for urine

Oogenesis & the Cyclic Events

• Oogenesis
– Meiosis yields haploid gamete; inherently cyclic (≈ 1 secondary oocyte/mo)
– Coupled to fluctuations of hypothalamic-pituitary-ovarian (HPO) axis

• Sexual Cycle (average 2828 days; physiologic range 20–4520\text{–}45 days)
– Hypothalamus secretes GnRH (pulsatile) → stimulates anterior pituitary
– Anterior pituitary releases FSH & LH → act on ovarian follicles
– Ovarian steroids (estradiol, progesterone, inhibin) exert feedback on both brain levels
– Two parallel but inter-dependent tracks:
• Ovarian cycle – events in ovary
• Menstrual (uterine) cycle – endometrial changes

Ovarian Cycle

  1. Follicular Phase (Day 1–141\text{–}14)
    • FSH → growth of a cohort of follicles → rising estradiol
    • Estradiol up-regulates its own receptors & LH receptors on dominant follicle
    • Rising estradiol + GnRH pulse frequency → positive feedback surge of LH (and lesser FSH)
    • LH surge triggers completion of Meiosis I in oocyte + ovulation

  2. Ovulation (≈ Day 1414)
    • Follicle ruptures; secondary oocyte + corona radiata released into peritoneal cavity; fimbriae sweep into tube

  3. Luteal Phase (Day 15–2815\text{–}28)
    • LH drives transformation of ruptured follicle → corpus luteum (CL)
    • CL secretes high progesterone + moderate estradiol → prepare endometrium (secretory phenotype)
    • High P/E + inhibin → negative feedback ↓LH/FSH
    • If no fertilization → CL degenerates (corpus albicans), steroid levels fall, spiral artery spasm → menses

Menstrual (Uterine) Cycle

• Proliferative Phase (overlaps follicular; estrogen-dominated)
– Rapid rebuilding & thickening of stratum functionalis
• Secretory Phase (overlaps luteal; progesterone-dominated)
– Endometrium becomes highly vascular, tortuous glands secrete glycogen-rich mucus
• Menstrual Phase
– Progesterone withdrawal → ischemia, tissue necrosis, shedding & vaginal bleeding

Contraception Strategies

• Abstinence – 100 % effective; behavioral
• Barrier + Spermicidal
– Male/Female condoms (also reduce STI spread)
– Diaphragm; Cervical sponge
• Surgical Sterilization
– Vasectomy (ductus deferens ligation)
– Tubal ligation (uterine tubes cut/occluded)
• Hormonal Approaches – mimic luteal negative feedback → block ovulation
– Combined oral pill (estrogen + progestin)
– Depot medroxyprogesterone injection every 33 mo
– “Morning-after” ECPs (high E/P or P only) if taken ≤ 120120 h post-intercourse → induce withdrawal bleed
• Intrauterine Devices (IUDs)
– Hormonal (levonorgestrel; e.g., Mirena)
– Copper (ParaGard) – spermicidal & inflammatory endometrial effect

Fertilisation → Pregnancy & Birth

• Copulation window: −72−72 h to +24+24 h around ovulation
• Ejaculated sperm initially ≈ 5 in5\,\text{in} from oocyte yet may need 1–21\text{–}2 h migration; only 200–1000200\text{–}1000 reach ampulla
• Barriers encountered
– Corona radiata (loose)
– Zona pellucida – breached via acrosome enzymes
• Fast block to polyspermy: oocyte membrane depolarisation; cortical reaction
• Secondary oocyte completes Meiosis II → forms 11 ovum + 33 polar bodies; paternal & maternal pronuclei merge → zygote
• Early Pregnancy physiology
– Uterus mass ↑ from ≈50 g\approx 50\,g → ≈900 g\approx 900\,g
– Skin stretches; increased fat deposition (hips, thighs)
– By 77-mo fetus rotates to vertex position (head-down)
– Near term: ↑ uterine OT receptors + posterior pituitary OT release → myometrial contractions (positive feedback loop)
• Placenta
– Maternal–fetal barrier (no blood mix)
– Functions: nutrient & O$_2$ delivery, waste removal, endocrine (E, P, hCG, etc.) – replaces CL by month 22
• Lactation reflex
– Suckling → hypothalamus →
• PRF/↓PIH → anterior pituitary prolactin (milk production)
• Oxytocin from posterior pituitary (milk let-down)
– Prolactin suppresses GnRH → natural but unreliable contraception

Menopause

• Defined: absence of menses ≥ 1212 months
• Average onset 45–5545\text{–}55 y
• Ovarian follicle pool exhausted → ↓E/Prog → cessation of reproductive capacity
• No exact male counterpart, but gradual androgen decline occurs

Disorders & Pathophysiology

Menstrual Abnormalities

• Amenorrhea – primary/secondary absence of menses
– Causes: hormonal imbalance, stress, tumors (ovarian/adrenal/pituitary)
– Tx: address etiology, hormonal therapy, surgery

Uterine Position & Support

• Uterine prolapse – descent into vagina; due to pelvic floor relaxation (congenital, postpartum)

Pelvic Inflammatory Disease (PID)

• Common pathogens: Neisseria gonorrhoeae, Chlamydia trachomatis
• Predisposing factors: cervical mucus alterations, IUD insertion, surgery, post-partum
• S/Sx: lower abdo pain, cervical motion tenderness, fever, ↑WBC, purulent discharge
• Complications: infertility, ectopic pregnancy, abscess

Benign Growths

• Leiomyomas (fibroids)
– Most prevalent uterine tumor; peak reproductive years; ↑incidence in Black women (×3)
– Estrogen & GH stimulate growth
• Endometriosis
– Ectopic implants of endometrial tissue (ovary, peritoneum, oviduct, bladder, intestine) → cyclic bleeding, pain, adhesions

Malignancies

• Cervical Cancer
– Detected via Pap smear
– Major cause: persistent high-risk HPV infection; early sexual activity, multiple partners, other STIs contribute
• Endometrial (Uterine) Cancer
– Risks: infertility, late menopause (>5555 y), obesity, DM, HTN
– S/Sx: inter-menstrual or post-menopausal bleeding
• Breast Cancer
– Most common cancer in ♀ 25–7525\text{–}75 y; top mortality 40–4440\text{–}44 y
– Risk modifiers:
• Reproductive – early first birth (<1818 y) ↓risk; late first birth (>3535) & nulliparity ↑risk; breastfeeding ↓risk
• Genetics – BRCA1/BRCA2
– Pathogenesis: ductal epithelial origin → local invasion → axillary lymph nodes → distant mets (liver, lung, bone)
– Prognosis: 98%98\% 5-yr survival if nodes ‑ve vs 23%23\% w/ distant mets

Pregnancy-Specific Disorder

• Pregnancy-Induced Hypertension (PIH / pre-eclampsia–eclampsia)
– Incidence 0.5–10%0.5\text{–}10\%; leading maternal mortality cause
– Characterized by rapid ↑BP + proteinuria

Sexually Transmitted Infections (STIs)

• Definition: transmissible via sexual contact; 1919 million new US infections/yr; highest in 15–2515\text{–}25 y
• Transmission can be vertical (mother → neonate)
• Categorized by pathogen: bacterial, viral, fungal, protozoal

Specific STIs

• Gonorrhea (Neisseria gonorrhoeae)
– Urethritis, cervicitis, salpingitis → PID
• Syphilis (Treponema pallidum)
– Systemic vascular infection; spreads during incubation; linked to high-risk behaviour incl. MSM
• Herpes Simplex Virus
– HSV-1: oral > genital but can cross
– HSV-2: genital > oral; 1 in 5 adults; neonatal transmission risk
• Human Papillomavirus (HPV)
– Types 6,11,16,18 most clinically important
• 16 & 18 → ≈70%\approx70\% cervical cancers
• 6 & 11 → ≈90%\approx90\% genital warts
– Extremely contagious (≈23\tfrac{2}{3} transmission rate) & may persist even after lesion removal

Ethical & Public-Health Connections

• Early detection (Pap test, mammography) significantly improves outcomes
• Vaccination (HPV) exemplifies preventive medicine bridging oncology & infectious disease
• Contraceptive choice impacts individual autonomy, STI control, and broader demographic trends
• Positive feedback in labor is a classic endocrine illustration of physiological amplification

Key Numbers, Equations & Mnemonics

• Sexual cycle length xˉ=28 days\bar{x}=28\,\text{days} (range 20–4520–45)
• Uterus mass: 50 g→900 g50\,g \rightarrow 900\,g by term
• Copulation window: −72−72 h to +24+24 h of ovulation
• Sperm attrition: ≤1 000/hundreds of millions\le 1\,000/\text{hundreds of millions} reach oocyte
• Breast CA 5-yr survival
– No nodes =98%=98\%; distant mets =23%=23\%
• PID organisms pneumonic: "Girls Catch Nasty Cramps" → Gonorrhea, Chlamydia, Neisseria, Cervicitis leading to pain