Overview of the Male Reproductive System

The purpose of the male reproductive tract is to produce, maintain, and transport sperm in a protective fluid (semen). Male reproduction involves discharging sperm into the female reproductive tract, as well as producing and secreting male sex hormones. The male reproductive system is complex and has many components.


External Reproductive Structures

Most of the male reproductive structures are located outside of the pelvis and abdominal cavity. External reproductive structures include:


  • Penis – The main sex organ is the penis. The root attaches to the abdomen wall, the body is the main component, and the glans is the cone-shaped end (head). The glans is covered with foreskin, which is a loose layer of skin. The tube that transports urine and semen is the urethra, which opens at the tip of the glans. The body of the penis has three internal chambers, which are composed of sponge-like erectile tissues. The tissue contain many large spaces that fill up with blood during sexual arousal. After the penis becomes rigid and erect, it can penetrate the female during intercourse. Semen is the fluid ejaculated (expelled) when the man reaches orgasm (sexual climax). The semen contain sperm, which fertilized the female’s egg.


  • Scrotum – The scrotum is a loose skin sac that hangs directly behind the penis. Two of these sacs contain testicles (testes) along with blood vessels and nerves. For normal sperm development, the testes must have a cooler body temperature than the body. The scrotum has special muscles that contract and relax so the testicles move closer to the body for protection and warmth or away from the body to cool down.


  • Testes – The testes are small oval organs that are secured at each end by the spermatic cord. The two testes are housed in the scrotum, and they are responsible for making the primary male sex hormone called testosterone. Coiled masses of tubes (seminiferous tubules) are responsible for producing sperm cells in the spermatogenesis process.


  • Epididymis – This long, coiled tube runs along the posterior region of each testicle. The epididymis stores sperm cells that mature. During sexual intercourse, contractions force the sperm into the vas deferens.


Internal Reproductive Organs

The male reproductive system has several accessory organs housed inside the body. These include:


  • Vas deferens – This is a muscular tube that runs form the epididymis to the pelvic cavity. The vas deferens lies behind the bladder and transports mature sperm into the urethra during ejaculation.
  • Ejaculatory ducts – These tiny ducts empty into the urethra and are formed by fusion of the seminal vesicles and the vas deferens.
  • Urethra – This is the tube that extends form the bladder to the tip of the penis. The urethra expels semen during orgasm. In addition, the flow of urine is blocked when the penis is erect.
  • Seminal vesicles – Sac-like pouches attach to the vas deferens and are positioned at the base of the bladder. These structures produce a fructose (sugar) fluid that gives sperm energy and assists with motility. The seminal vesicle fluid makes up the majority of the semen.
  • Prostate gland – This walnut-sized structure lies below the urinary bladder and right in front of the rectum. This gland adds fluid to the ejaculate that nourishes sperm. The urethra will expel this fluid during orgasm.
  • Bulbourethral glands – Called Cowper’s glands, these pea-sized structures like on either side of the urethra and right below the prostate. These glands produce a fluid that lubricates the urethra and neutralizes acidity.