Male Anatomy and Physiology
Father and teenage sonExternal Parts and Functions
- Penis: The male sex organ, also used for urination
- Testicles (testes): Two round glands that descend into the scrotum following birth; produce and store sperm from puberty onward; produce the male sex hormone, testosterone
- Scrotum: The pouch located behind the penis; holds and provides protection to the testicles; maintains the temperature necessary for the production and survival of sperm
- Anus: The opening for the expulsion of feces from the body (not a part of the reproductive system)
- Circumcision: The removal of the foreskin, which covers the head (glans) of the penis; a procedure usually performed during the first 10 days of life for religious and/or personal reasons; does not affect a man’s ability to have sex
- Erection: The process by which the penis fills with blood and becomes hard in response to thoughts, fantasies, temperature, touch or sexual stimulation
Internal Parts and Functions
- Vas Deferens: Passageway for sperm; one leads from each testicle to join with the urethra. This is the structure that a doctor cuts to perform a vasectomy, one of the few birth control methods for men
- Seminal vesicles: Two sac-like structures lying behind the bladder; secrete a thick fluid that form part of the semen
- Prostate gland: Gland located in the male pelvis; secretes a thick, milky fluid that forms part of the semen. This fluid provided nutrients for the sperm and makes the sperm more mobile.
- Cowper’s glands: Two small glands that secrete a fluid released from the penis soon after erection; the function of this fluid, which may contain sperm, is to neutralize the acid in the urethra, making that passageway safe for sperm.
- Urethra: The tube through which urine passes from the bladder to outside the body; also the passageway for semen as it leaves the body; closed to urine during ejaculation.
- Sperm: The male sex cells; too small to be seen without a microscope; shaped like tadpoles; movement aided by lashing of tails; production usually begins at age 12-14; total number per ejaculation: 200-500 million; may survive in the female’s Fallopian Tubes for as long as 7 days, but rarely cause fertilization after 72 hours. Only one of these hundreds of millions of cells needs to penetrate (fertilize) a woman’s egg to start the development of a fetus (baby).
Semen: The sperm-containing fluid that passes out of the penis at the time of ejaculation; the fluids that later mix with sperm are produced and stored in the seminal vesicles and prostate gland; young males’ semen is clear due to low sperm count; whitish color develops as the sperm count increases; whether clear or white, a male’s semen is capable of impregnating a female.
- Ejaculation: The release of semen from the penis
- Nocturnal emissions (wet dreams): Erection of the penis and subsequent ejaculation during sleep; nature’s way of releasing excess sperm from the testicles; usually triggered by sexual dreams and fantasies; occurs most frequently in males who do not engage in masturbation or sexual intercourse.
Click here for an interactive diagram of the male reproductive system