Anatomy WK 12 (4/22) | Notes on Female and Male Reproductive Anatomy

Overview of Female Reproductive Anatomy

  • Uterus and Hormones
    • Importance of uterus in reproduction.
    • Hormones play a major role in the cycles involving ovaries and uterus.

Connection to the Outside World

  • Vaginal Canal

    • Passageway for sperm to enter and for childbirth.
    • Located at the bottom of the uterus where it projects into the vaginal canal.
    • Lined with epithelium and smooth muscle, facilitating function.
    • Starts at the cervix (external os) and opens to the outside (external vaginal orifice).

  • Structure of Vaginal Canal

    • Internal and external orifices.
    • Rugae: folds in the vaginal walls that allow for expansion during childbirth.
    • Histology includes:
    • Stratified squamous epithelium for durability against pressure/friction.
    • Lamina Propria: connective tissue with collagen, providing structure.
    • Fibromuscular Layer: contains smooth muscle for contractions.
    • Adventitia: outer lining of the vaginal canal.

Childbirth Mechanics

  • Vaginal canal adapts for the childbirth process.
    • Both dilation of the cervix and expansion of the vaginal canal are critical for allowing the baby to pass through.

External Genitalia (Vulva)

  • Purpose: To protect internal structures and separate them from the outside environment.
  • Involved Structures:
    • Vaginal Orifice: entry point for the vagina.
    • External Urethral Orifice: where urine exits.
    • Labia Minora: smaller folds covering the orifices, creating a vestibule.
    • Labia Majora: larger outer folds, thicker, hairy skin.
    • Mons Pubis: subcutaneous fat cushion at pelvic bones.
    • Clitoris:
    • Exposed portion (glans) covered by prepuce; contains erectile tissue similar to male anatomy.

Clitoral Anatomy and Function

  • Clitoris has internal portions extending into the vestibule, including:
    • Crus: splits internally and made up of erectile tissue.
    • Bulb of the Vestibule: erectile tissue that aids in sexual arousal and lubrication of the vagina.
  • Sexual Stimulation: Increased blood flow causes engorgement, elevating the glands and exposing them for stimulation, while also potentially aiding vaginal secretions.

Embryonic Development Origins

  • Common embryonic origin of male and female genitalia explains similar structures:
    • Genital tubercle, urogenital folds, and other structures differentiate based on chromosomes leading to sexual dimorphism.
  • Comparative Structures:
    • Clitoris (female) and penis (male) share common embryonic origins.

Male Reproductive System Overview

  • Focused on Testes: where sperm and hormones like testosterone are produced.
  • Epididymis: storage for mature sperm.
  • Ductus Deferens: pathway carrying sperm from testes upward toward urinary system.

Testicular Function

  • Spermatogenesis:
    • Occurs within seminiferous tubules.
    • Leydig Cells: produce testosterone.
    • Spermatogonia: undergo meiosis, developing into sperm (via primary, secondary spermatocytes).
    • Sertoli Cells: nourish maturing sperm.

Temperature Regulation of Testes

  • Cremaster and Dartos Muscles:
    • Regulate distance and thickness of scrotum for temperature control of testes, critical for optimal sperm production.

Testicular Issues

  • Testicular Torsion: dangerous condition; twisting impairs blood flow, requires immediate treatment.
  • Symptoms include severe pain and swelling.

Accessory Glands and Their Role

  • Seminal Vesicles: provide fluid for sperm transport.
  • Prostate Gland: secretes fluids to support and protect sperm; its enlargement can obstruct urine flow.
  • Bulbo-Urethral Glands: produce pre-ejaculate fluid for lubrication.

Ejaculation Overview

  • Ejaculatory Duct: pathway where sperm and secretions from glands exit urethra during ejaculation.

Prostate Health

  • Benign Prostatic Hyperplasia (BPH):
    • Common in older men; enlarged prostate restricts urine flow due to increased cell production.
  • Treatments include medication and surgical options like TURP to alleviate obstruction.