Sexual health library // Resources and More info // You and your body // Penises, Scrotums, Testes and more

The Penis, Scrotum, testicles and more

The biological male reproductive/sexual system is made up of the organs that allow a male to:

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

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

Internal sex organs

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

Male body diagram of testes and scrotum

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

Male body part: epididymis diagram

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

Diagram of the vas deferens in relation to penis

Urethra

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

male body part diagram: urethra

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

pullout diagram of seminal vesicle

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

Prostate gland diagram inside male body

External  sexual organs

male body part close up diagram of 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

Scrotum

  • The two testes are contained in the scrotum outside the body, in order to maintain the right temperature for sperm to be produced