The scrotum and the penis are the male genitalia.  The male gonads, called testis, are tightly coiled tubes surrounded by tissue.  It is in these tubes where sperm forms.  The male gonads are located outside of the body since sperm productions can only occur at a lower than normal body temperature.  After the sperm are produced they mature and are stored in the epididymus.

     The male reproductive system also contains three sets of glands that add secretions to the semen.  Sixty percent of semen is secreted by the seminal vesicles.  They lie behind and below the bladder and empty directly into the ejaculatory duct.  The fluid secreted is clear yet thick.  It contains mucus, amino acids, and fructose.  The fructose provides energy for the sperm.

     The prostate gland surrounds the beginning of the urethra in which it secretes its products.  Prostatic fluid is milky, thin, and alkaline in order to balance the acidity of any urine remaining in the urethra and the acidity of vaginal fluids.

     Bulbourethral glands lie along the urethra below the prostate.  Although their specific function is still unknown, they do secrete a viscous fluid before ejaculation.

     Three layers of spongy tissue comprise the human penis.  When sexually aroused, this tissue fills with blood from the arteries , while the veins are sealed.  This produces an erection.

     The shaft of the penis is covered in relatively thick skin.  The head, or glans penis, is covered with thinner skin.  This results in extra sensitivity in the glans penis area.