Describe the Male Reproductive System?
In addition to the primary sex organs, the testes, there are accessory structures that store, nourish, and activate the sperm, and conduct them to the egg in the female reproductive tract. The seminiferous tubules merge to form a coiled duct known as the epididymis. The epididymis is where sperm are stored, and it is where they undergo the final maturation process. The epididymis extends into the body cavity and becomes the vas deferens. The vas deferens eventually leads into the urethra, the tube that carries the sperm and other fluids to the outside of the body through the penis. The urethra also serves as a passageway for urine, but a membrane prevents either from passing at the same time.
There are three glands whose secretions empty into the vas deferens or urethra: the seminal vesicles, the prostate gland, and the bulbourethral or Cowper's glands. The secretions of these glands provide nutrients to nourish the sperm, substances to activate swimming by the sperm, and fluids that are designed to neutralize acid in the urethra and in the female reproductive tract. The sperm and these secretions together form the fluid known as semen.
The penis is the exterior male organ that is used to carry out internal fertilization of the egg within the female's reproductive tract. The penis' structure is well-suited to its function, which is to deliver the semen and sperm as close to the awaiting egg as possible. Structurally, it is an organ that is composed of sheaths of spongy tissue that can be extended and inserted into the female's body. During sexual stimulation, hollow spaces in these sheaths become filled with blood. This blood presses against the walls of the veins, so that the flow of blood from the penis is restricted. This blood under pressure causes the penis to enlarge and become erect. When the penis is inserted into the vagina during sexual intercourse, stimulation of the sensitive glans penis may result in an orgasm, which in males is usually accompanied by waves of strong muscular contractions in the sperm ducts and the forceful release of semen called ejaculation.