Functional Anatomy of Reproductive System

Male Reproductive Functional Anatomy - Testes & Tubes

• Testes: Paired; sperm (spermatogenesis) & testosterone production.
  • Seminiferous Tubules: Sperm production. Contain Sertoli cells.
  • Sertoli Cells: Support spermatogenesis; blood-testis barrier; secrete inhibin, ABP.

    ⭐ Sertoli cells form the blood-testis barrier, protecting sperm from immune attack.

  • Leydig Cells: Interstitial; testosterone production (LH-driven).
• Duct System:
  • Epididymis: Sperm maturation (motility), storage.
  • Vas Deferens: Transports sperm to ejaculatory duct.
  • Ejaculatory Duct: Vas deferens + seminal vesicle duct; via prostate.
• Accessory Glands: Contribute to semen.
  • Seminal Vesicles: Alkaline, fructose fluid (~65-75% vol).
  • Prostate Gland: Milky fluid, enzymes (PSA) (~25-30% vol).
  • Bulbourethral Glands: Pre-ejaculate; neutralizes urethral acid.

• Sperm Pathway: 📌 SEVEN UP

*(S: Seminiferous tubules, E: Epididymis, V: Vas deferens, E: Ejaculatory duct, N: Nothing, U: Urethra, P: Penis)*

Female Reproductive Functional Anatomy - Ovaries & Uterus

• Ovaries: Paired gonads.
  • Folliculogenesis: Primordial follicle → Graafian follicle. Ovulation (LH surge).
  • Corpus Luteum: Secretes progesterone & estrogen; regresses to corpus albicans if no fertilization.
• Fallopian Tubes (Uterine Tubes):
  • Parts: Infundibulum (fimbriae), Ampulla, Isthmus, Intramural part.
  • Function: Oocyte transport via ciliary action & peristalsis.

  ⭐ Fertilization typically occurs in the ampulla.

• Uterus:
  • Layers: Perimetrium (outer serosa), Myometrium (smooth muscle, contractions), Endometrium (inner lining; stratum basalis & functionalis).
  • Cyclical Changes (Endometrium):
    • Menstrual (Days 1-5): Stratum functionalis shed.
    • Proliferative (Days 6-14): Estrogen-driven regrowth of functionalis.
    • Secretory (Days 15-28): Progesterone-driven; glandular, vascular, ready for implantation.
• Cervix: Lower, narrow part of uterus; cyclical mucus changes.
• Vagina: Fibromuscular tube; birth canal; acidic pH (Döderlein's bacilli).
• Support & Vasculature (Functional Relevance):
  • Ligaments: Broad lig. (drape), Round lig. (maintains anteversion), Cardinal lig. (main support), Ovarian lig. (ovary to uterus), Suspensory lig. (contains ovarian vessels).
  • Blood Supply: Ovarian artery (from abdominal aorta), Uterine artery (from internal iliac artery).

Gametogenesis Functional Aspects - Making Babies 101

Spermatogenesis:

• Site: Seminiferous tubules. Continuous from puberty. Duration: ~74 days.
• Stages: Spermatogonia (2n) → Primary spermatocyte (2n) → Secondary spermatocyte (n) → Spermatid (n) → Spermatozoa (n).
• Spermiogenesis: Spermatid maturation (acrosome, flagellum). Yields 4 sperm.

![Spermatogenesis process diagram](https://ylbwdadhbcjolwylidja.supabase.co/storage/v1/object/public/notes/L1/Anatomy_Functional_Anatomy_Functional_Anatomy_of_Reproductive_System/d67315d7-0aee-43cf-85b4-af572785220d.png)

Oogenesis:

• Site: Ovary. Discontinuous; starts prenatally, resumes at puberty.
• Stages: Oogonium (2n) → Primary oocyte (2n) → Secondary oocyte (n) + 1st polar body. Yields 1 ovum.

  ⭐ Key Arrests: Primary oocytes in Prophase I (birth to puberty); Secondary oocytes in Metaphase II (ovulation to fertilization).

![Oogenesis Process Diagram](https://ylbwdadhbcjolwylidja.supabase.co/storage/v1/object/public/notes/L1/Anatomy_Functional_Anatomy_Functional_Anatomy_of_Reproductive_System/65fc22c0-9a8f-4923-a612-8aa062ce8666.jpg)

Mature Gametes:

• Sperm: Head (acrosome, nucleus n=23), Midpiece (mitochondria), Tail.
• Ovum: Zona pellucida, Corona radiata, nucleus (n=23).

Reproductive Hormonal Control - Reproductive Orchestra

HPG Axis: Hypothalamus (GnRH) → Pituitary (LH/FSH) → Gonads (Steroids, Inhibin).

• Key Hormones & Roles:

  • GnRH (Hypothalamus): Stimulates LH/FSH release.
  • LH (Ant. Pituitary): M: Testosterone (Leydig). F: Ovulation trigger, corpus luteum.
  • FSH (Ant. Pituitary): M: Spermatogenesis (Sertoli), Inhibin. F: Follicular growth, Estrogen (Granulosa).
  • Testosterone (Leydig): Male characteristics, spermatogenesis.
  • Estrogen (Ovarian follicles/Corpus Luteum): Female characteristics, endometrial proliferation.
  • Progesterone (Corpus Luteum/Placenta): Maintains pregnancy, endometrial secretory phase.
  • Inhibin (Sertoli/Granulosa): ↓FSH. Activin (Sertoli/Granulosa): ↑FSH.

• Menstrual Cycle: Coordinated E, P, LH, FSH changes regulate follicular, ovulatory, luteal phases.

⭐ LH Surge: A rapid ↑ in LH, triggered by sustained high estrogen (positive feedback), is crucial for ovulation.

High‑Yield Points - ⚡ Biggest Takeaways

• Spermatogenesis occurs in seminiferous tubules; sperm matures in the epididymis.
• Leydig cells synthesize testosterone; Sertoli cells support spermatogenesis.
• Oogenesis: primary oocytes arrest in prophase I; secondary oocytes in metaphase II.
• Fertilization most commonly occurs in the ampulla of the uterine tube.
• Corpus luteum produces progesterone, essential for maintaining early pregnancy.
• Endometrium: stratum functionalis sheds; stratum basalis regenerates the lining.
• Pampiniform plexus cools arterial blood to testes via countercurrent exchange_._