Urogenital Organs

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Urinary Bladder & Urethra - Bladder & Urethra Blueprint

  • Urinary Bladder:
    • Hollow muscular organ; urothelium.
    • Parts: Apex, body, fundus, neck. Trigone: smooth.
    • Detrusor: Smooth muscle for micturition.
    • Capacity: 400-600 mL. Urge: 150-200 mL.
    • Innervation:
      • Parasympathetic (S2-S4): Micturition (contracts detrusor).
      • Sympathetic (T11-L2): Storage (relaxes detrusor).
      • Somatic (Pudendal n.): External sphincter (voluntary).
    • Arteries: Sup. & Inf. vesical aa. (internal iliac a.). Urinary bladder anatomy with histology
  • Urethra:
    • Male Urethra (~20 cm):
      • Parts: Pre-prostatic, Prostatic (widest), Membranous (narrowest, ext. sphincter), Spongy (longest). (PPMMS)
      • 📌 Mnemonic: "Prostitutes Prefer Making Money Standing".
    • Female Urethra (~4 cm):
      • Shorter, anterior to vagina; ↑UTI risk.
      • Skene's glands (prostate homologue).

    ⭐ The membranous urethra in males is the narrowest and least distensible part, most prone to rupture during instrumentation.

Male Urogenital Organs - Gents' Gear & Ducts

  • Testes & Epididymis
    • Testes: Paired oval glands in scrotum; produce sperm & testosterone. Tunica albuginea (fibrous capsule), septa divide into lobules containing seminiferous tubules.
    • Epididymis: Coiled tube on posterior testis; sperm maturation & storage. Head, body, tail (continuous with ductus deferens).
    • Blood Supply: Testicular artery (from aorta).
    • Innervation: Testicular plexus. Testis and Epididymis Sagittal View
  • Ductus (Vas) Deferens
    • Muscular tube; transports sperm from epididymis to ejaculatory duct.
    • Part of spermatic cord.
  • Seminal Vesicles
    • Paired glands posterior to bladder; produce ~70% of seminal fluid (alkaline, fructose-rich).
    • Duct joins ductus deferens to form ejaculatory duct.
  • Ejaculatory Ducts
    • Formed by union of ductus deferens & seminal vesicle duct; pass through prostate to empty into prostatic urethra.
  • Prostate Gland
    • Walnut-sized gland inferior to bladder, surrounds prostatic urethra.
    • Produces ~25% of seminal fluid (milky, slightly acidic, contains PSA).
    • Zones: Peripheral (common site of cancer), central, transitional (BPH).

    Clinical Pearl: The neurovascular bundles supplying the penis run posterolaterally to the prostate; crucial to preserve during prostatectomy to maintain erectile function.

  • Bulbourethral (Cowper's) Glands
    • Pea-sized, posterolateral to membranous urethra; secrete pre-ejaculate (lubrication).
  • Penis & Urethra
    • Penis: Corpora cavernosa (2, dorsal), corpus spongiosum (1, ventral, contains urethra).
    • Urethra: Prostatic, membranous, spongy (penile).

Female Urogenital Organs - Ladies' Layout & Lifeline

  • Ovaries: Paired, in ovarian fossa.
    • Function: Oogenesis, hormone production (estrogen, progesterone).
    • Ligaments: Suspensory (vessels), Ovarian.
    • Blood: Ovarian a. (aorta); R vein to IVC, L vein to L renal v.
  • Uterine Tubes (Fallopian): ~10 cm.
    • Parts: Infundibulum (fimbriae), Ampulla (fertilization), Isthmus, Intramural.
  • Uterus: Pear-shaped.
    • Parts: Fundus, Body, Cervix. Layers: Peri-, Myo-, Endometrium (cyclic changes).
    • Position: Anteverted, anteflexed.
    • Supports: Broad lig., Round lig., Cardinal lig. (primary), Uterosacral lig.
    • Blood: Uterine a. (internal iliac a.).

    ⭐ Uterine artery crosses superior to ureter. 📌 "Water (ureter) under the bridge (uterine a.)".

  • Vagina: Fibromuscular tube (~8-10 cm); cervix to vestibule. Fornices.
  • Vulva: Mons pubis, Labia majora/minora, Clitoris, Vestibule (urethral/vaginal orifices, Bartholin's glands).
  • Urethra: Short (~4 cm); opens in vestibule; prone to UTIs.

Female urogenital system sagittal view

High‑Yield Points - ⚡ Biggest Takeaways

  • Ureter is inferior to uterine artery ("water under bridge") near lateral vaginal fornix.
  • Pudendal nerve (S2-S4): main motor/sensory supply to perineum.
  • Membranous urethra: shortest, narrowest, least dilatable; prone to rupture.
  • Micturition: parasympathetic (S2-S4) stimulates detrusor. Storage: sympathetic (T11-L2).
  • Cardinal ligament: strongest support for uterus/cervix.
  • Testicular/Ovarian arteries: arise from abdominal aorta (L2).
  • Prostatic venous plexus drains to vertebral plexus (Batson's): metastasis route.

Practice Questions: Urogenital Organs

Test your understanding with these related questions

Which structure provides level 1 support for the uterus and vagina?

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Flashcards: Urogenital Organs

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The _____ lobe of the prostate forms the uvula vesicae.

TAP TO REVEAL ANSWER

The _____ lobe of the prostate forms the uvula vesicae.

median

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