Human Anatomy

How An Erection Works

Institute of Human Anatomy

• Glans Penis
  • ‘Glans’ means ‘acorn’
  • Pudendal Nerve
  • Spinal Cord
  • Lower spinal cord reflexive penile function
  • Parasympathetic Nervous System
    • s2, s3, s4 -s 2 3 and 4 keeps the penis off the floor
  • 3 cylindrical masses of erectile tissue
    • corpus spongiosum, ‘body spongy’
    • corpora cavernosa, ‘body cavern’
      • epithelial + muscle cells
      • deep artery
      • $N_1O_1$
        • vasodilate and relax -> expansion

Summary: The penis can be exited psychologically or locally via the Pudendal Nerve. This stimulation makes its way throught the spinal cord near s2-4. The penis is made of two cylinders of corpus cavernosa and below it the corpus spongiosum. The spongiosum keeps the urethra uncollapsed. The corpus cavernosa tissue is made of epithelial and muscle cells, and has its blood supplied via an artery that also releases nitrous oxide to expand the cavity.