The penis is part of the male reproductive system. Together with the testicles, it forms the male external genitalia. The penis also has a function in the urinary system. The penis is an external organ, consisting of the glans at the tip and the penis.

The penis therefore has a dual function - reproduction and elimination of urine. The human penis does not contain bones but two structures called carvernous bodies which will fill with blood and cause stiffening. The penis is composed of three layers of tissue: the two corpora cavernosa and the corpus spongiosum. The urethra, which is the last part of the urinary tract, passes through the corpus spongiosum. The urethra is the conduit that allows both the transport of urine from the bladder to the external environment during micturition, but also the ejaculation allowing the exit of sperm containing male gametes called spermatozoa, male reproductive cells.