Island Sexual Health Society Be informed, not surprised!

Male sexual anatomy

2006 June 08

The male reproductive system is made up of the organs that allow a man to:

* have and enjoy sexual intercourse
* produce sperm (male sex cells)
* fertilize ova (eggs) with sperm

The sexual organs of the male are partly visible and partly hidden within the body.

* “Inside parts”:#inside
* “Outside parts”:#outside

h3(#inside). Internal male sex organs

h4(#testes). Testes

* Oval-shaped glands that are about 4cm in length and 3cm in width
* The testes make millions of sperm every day and also secrete the male sex hormones
* The testes are sensitive to touch

h4(#epididymis). Epididymis

* Highly coiled tube that lies around the back of the testicle
* Sperm are passed to the epididymis from the testes where they are made
* Sperm is stored in the epididymis for about 20 days until they are mature
* Once mature the sperm move to the vas deferens
* The testes and epididymis form each testicle

h4(#vas). Vas deferens

* About 45cm (18 inches) long and runs from the epididymis to the urethra
* It carries the sperm from the testes to the urethra and stores it prior to ejaculation
* The sperm become mixed with secretions along the way and form semen

h4(#urethra). Urethra

* Tube that links the vas deferens to the outside
* Also runs from the bladder, serving both the urinary and reproductive systems

h4(#vesicle). Seminal vesicles

* Lie behind the bladder and produce the secretion which makes up 60% of the semen
* These secretions contain fructose which acts as a fuel for the sperm

h4(#prostate). Prostate gland

* Is just below the bladder and is about the size of a chestnut
* Makes secretions which make up about 30% of the semen
* These secretions make the vagina less acidic so that sperm can survive better

h3(#outside). External male sexual organs

h4(#penis). Penis

* Consists of the shaft and the head (called the glans)
* The glans, the corona (the rim of the glans) and the frenulum (tissue that links the underside of the glans and the shaft) are very sensitive and play a big role in sexual pleasure
* Some men are circumcised which means that the foreskin (skin covering the head of the penis) has been cut away; on an uncircumcised penis the loose foreskin is still covering the head of the penis but can be slid back
* Inside the penis is the urethra, carrying sperm and urine to the outside of the body
* During sexual arousal, the penis becomes filled with blood and becomes erect
* The average flaccid penis is 8-10cm long and the average erect penis is 15cm long
* There is considerable variation in the size of a flaccid penis but not very much variation in the size of an erect penis
* During ejaculation, between 300 and 500 million sperm are released

h4(#scrotum). Scrotum

* The two testes are contained in the scrotum outside the body, in order to maintain the right temperature