Male reproductive system

The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction. These organs are located on the outside of the body and within the pelvis. The main male sex organs are the penis and the scrotum which contains the testicles that produce semen and sperm, which, as part of sexual intercourse, fertilize an ovum in the female's body; the fertilized ovum (zygote) develops into a fetus, which is later born as an infant. The corresponding system in females is the female reproductive system. Human penis The penis is the male intromittent organ. It has a long shaft and an enlarged bulbous-shaped tip called the glans, which supports and is protected by the foreskin. Inside the penis is the urethra, which is used to ejaculate semen and to excrete urine. Both substances exit through the meatus. When the male becomes sexually aroused, the penis becomes erect and ready for sexual activity. Erection occurs because sinuses within the erectile tissue of the penis become filled with blood. The arteries of the penis are dilated while the veins are compressed so that blood flows into the erectile cartilage under pressure. The penis is supplied by the pudendal artery. Scrotum The scrotum is a pouch-like structure that hangs behind the penis. It holds and protects the testicles. It also contains numerous nerves and blood vessels. During times of lower temperatures, the cremaster muscle contracts and pulls the scrotum closer to the body, while the dartos muscle gives it a wrinkled appearance; when the temperature increases, the cremaster and dartos muscles relax to bring down the scrotum away from the body and remove the wrinkles respectively. The scrotum remains connected with the abdomen or pelvic cavity through the inguinal canal. (The spermatic cord, formed from spermatic artery, vein and nerve bound together with connective tissue passes into the testis through inguinal canal.