Male Reproductive Anatomy Explained

A plain-language overview of male reproductive anatomy, covering the external and internal organs, what each part does, and what is considered normal.

4 min read

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By Clarity Editorial Team

Reviewed for clarity and accuracy by our editorial team.

Published June 5, 2026

This article is grounded in guidance from authorities such as the WHO, CDC, NHS, and ACOG (see references). Independent review by a named healthcare professional is part of our ongoing editorial process.

The male reproductive system anatomy is made up of external organs (the penis, scrotum and testicles) and internal organs (the epididymis, vas deferens, seminal vesicles, prostate and urethra). Together these structures produce hormones, make and store sperm, and move it out of the body.

The external organs

The parts you can see and feel sit outside the body. Keeping the sperm-producing organs slightly cooler than core body temperature is one reason this anatomy is external.

The penis

The penis has three regions: the root (attached inside the body), the shaft (the main length), and the glans (the rounded tip). Running through it is the urethra, the tube that carries both urine and semen out of the body — though not at the same time.

Inside the shaft are columns of spongy tissue that fill with blood to produce an erection. If you want the mechanics behind that, see how erections work.

The scrotum and testicles

The scrotum is a pouch of skin and muscle that holds the testicles (testes). Small muscles let the scrotum move the testicles closer to or farther from the body to help regulate temperature, which matters because sperm production needs a temperature slightly below the rest of the body.

The two testicles are egg-shaped organs that:

produce sperm
produce the hormone testosterone

It is normal for one testicle to sit slightly lower or to be a little larger than the other.

The internal organs

Once sperm are made, a series of tubes and glands inside the pelvis store them and prepare semen.

The epididymis

The epididymis is a tightly coiled tube sitting against the back of each testicle. Sperm move here after they are made and mature over time before being stored, ready to be moved on.

The vas deferens

The vas deferens is a long muscular tube that carries mature sperm up from the epididymis toward the urethra. There is one on each side. (This is the tube cut or sealed during a vasectomy.)

The seminal vesicles and ejaculatory ducts

The two seminal vesicles are small glands that produce much of the fluid in semen, including sugars that help nourish sperm. Their ducts join the vas deferens to form the ejaculatory ducts, which empty into the urethra.

The prostate gland

The prostate is a walnut-sized gland below the bladder, in front of the rectum. It:

adds fluid that mixes with sperm to form semen
uses muscle to help push semen into the urethra

Because the urethra passes straight through the prostate, changes in the gland can affect urination. To go deeper, read what is the prostate.

The bulbourethral glands

Also called Cowper's glands, these two pea-sized glands sit below the prostate. They release a small amount of fluid into the urethra that helps lubricate it and neutralize any acidity before semen passes through.

How the parts work together

It helps to picture the system as a production line with three jobs:

Make — the testicles produce sperm and testosterone.
Store and mature — the epididymis holds sperm while they finish developing.
Mix and move — the vas deferens carries sperm while the seminal vesicles, prostate and Cowper's glands add fluid, forming semen that exits through the urethra.

The same urethra also carries urine from the bladder, which is why this anatomy is involved in both reproduction and urination.

How this anatomy connects to the rest of the body

Reproductive anatomy does not work in isolation. Testosterone made in the testicles travels through the bloodstream and influences muscle, bone, mood and sex drive across the body. The nervous system and blood vessels coordinate erections, and the bladder and urethra share space with reproductive structures.

For comparison and contrast, you can explore female reproductive anatomy or browse the full body and anatomy library for related guides.

The bottom line

Male reproductive anatomy combines external organs (penis, scrotum and testicles) with internal organs (epididymis, vas deferens, seminal vesicles, prostate and urethra) that together make hormones, produce and store sperm, and move it out of the body. Understanding how each part fits in makes it easier to recognize what is normal for you and to know when a change is worth a conversation with a healthcare provider.

Frequently asked questions

What are the main parts of the male reproductive system?

The system has external parts (penis, scrotum and testicles) and internal parts (epididymis, vas deferens, seminal vesicles, prostate, ejaculatory ducts and urethra). Together they produce hormones, make and store sperm, and move it out of the body.

What is the difference between the testicles and the scrotum?

The scrotum is the pouch of skin and muscle that holds the testicles. The testicles are the two egg-shaped organs inside it that actually make sperm and the hormone testosterone. The scrotum mainly protects them and helps keep them slightly cooler than body temperature.

Is it normal for one testicle to hang lower than the other?

Yes. It is very common and completely normal for one testicle to sit slightly lower or to be a little larger than the other. Knowing your own normal makes it easier to notice any changes, such as a new lump, swelling or pain, that should be checked by a provider.

What does the prostate gland do?

The prostate is a small, walnut-sized gland below the bladder. It produces fluid that mixes with sperm to form semen, and its muscle helps push semen through the urethra. Because the urethra runs through it, prostate changes can also affect urination.