Illustration of the male reproductive system. The male reproductive system is responsible for sexual intercourse, spermatogenesis (sperm production), the production and secretion of sex hormones and is involved in urination. The external components are the penis and testes (testicles). The internal components include the prostate (top right), vas deferens (sperm duct, ascending from the testes), epididymis (c-shaped structure right of testicle), seminal glands (not pictured) and urethra (tube from the bladder to the end of the penis).