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Overview of the Male Reproductive System

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The Manual's Editorial Staff

Last full review/revision Jun 2020| Content last modified Jun 2020
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What is the male reproductive system?

The male reproductive system is the system in a man's body with the purpose of making babies. Some parts of the male reproductive system, such as the penis and urethra, belong to the urinary system as well. The urinary system makes urine and passes it out of the body.

The male reproductive system includes the:

  • Testicles: Two testicles inside the scrotum make sperm and testosterone, a male sex hormone

  • Epididymis: Organ connected to the testicle in which sperm are collected and mature

  • Vas deferens: Tube that carries sperm from the epididymis to the penis

  • Seminal vesicles and prostate gland: Organs that make fluid for semen

  • Urethra: Tube that carries urine and semen through the penis

  • Penis: The man's sex organ that fills with blood during sexual arousal, causing an erection

Male Reproductive Organs

Male Reproductive Organs

How does the male reproductive system work?

The main activities of the male reproductive system include:

  • Puberty: Getting your body ready to produce sperm and have sex

  • Erection: Getting the penis stiff so that you can have sex

  • Ejaculation: Releasing semen

What are sperm and semen?

  • Sperm are the male sex cells, which can fertilize a female's egg and start a pregnancy

  • Semen is the liquid that contains sperm and comes out of your penis when you ejaculate

Your testicles make millions of sperm, which go into the epididymis to mature. Then they travel through a long tube called the vas deferens on their way to the urethra and out the penis.

Semen is made up of sperm and a lot of liquid that nourishes and transports the sperm. The liquid is produced by your seminal vesicles and prostate and mixes with sperm during ejaculation.

What is an erection?

An erection is when your penis gets bigger and stiff (erect). Erections happen when you're sexually aroused and is made possible by both physical and mental factors.

During an erection, the spaces inside your penis fill with blood, making the penis longer, wider, and more firm. Your penis fills with blood because the arteries that bring blood into the penis widen so more blood flows in, and the veins constrict so less blood flows out.

What is ejaculation?

Ejaculation is the release of semen from your penis. Sexual stimulation causes an orgasm (the peak of sexual excitement). During an orgasm, muscles squeeze and push semen into your urethra and out your penis.

What happens after ejaculation?

After ejaculation happens or if sexual stimulation stops, more blood flows out of your penis and less flows in, causing your penis to get limp. Another erection can’t happen for a period of time, usually about 20 minutes in young men.

What can go wrong with a man's reproductive system?

Some problems with a man's reproductive system involve hormones, for example:

Other reproductive system problems include:

Many diseases, such as infections and cancer, can affect a man's reproductive system.

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