What is the male reproductive system?
Your reproductive system is made up of many individual organs acting together. Some are visible, such as the penis and the scrotum. Some are hidden inside your body. The brain also has an important role in controlling your reproductive function.
Learn more about male hormones.
The penis is made up of two erectile cylinders (corpora cavernosa) that swell with blood during an erection. A tough, fibrous, partially elastic outer casing surrounds the two cylinders. Your urethra sits below the two cylinders and is surrounded by a spongy tissue (called the corpus spongiosum). If you’re uncircumcised, the head of the penis (glans penis) is covered by foreskin.
The urethra (you-ree-thrah) is a tube that runs from your bladder to the end of the penis. It carries urine and semen from your bladder to the outside of your body.
Your urethra is made up of two parts. The prostatic urethra is the part of the urethra that runs from your bladder through your prostate. The penile urethra is the part of your urethra that runs through the penis. A ring of muscle called the internal sphincter is located at the base of the bladder. When your internal sphincter closes, it stops urine leaving your body through the urethra. When you orgasm, this muscle ring closes tightly, to stop sperm passing backwards into the bladder.
The scrotum is a loose pouch of skin that hangs outside your body from your lower abdominal region behind the penis. Your scrotum holds your testicles in place, and helps to keep them cooler than your core body temperature.
The testes, or testicles, are a pair of egg shaped glands that sit in your scrotum, next to the base of the penis on the outside of the body. You need testicles for your reproductive system to work normally.
The testicles have two related, but separate roles:
• To make sperm
• To make testosterone.
The testicles develop inside the abdomen when you’re an unborn baby. They then move down (descend) into your scrotum before or just after birth. The descent of your testicles is important for your fertility, because your testicles need to be in a cooler temperature to make sperm and to work normally. In the scrotum, testicles are about 2°C cooler than normal core body temperature. This is why, in cold weather, the scrotum contracts and brings the testicles closer to the body, and relaxes in hotter weather.
Your epididymis (ep-ee-did-ee-miss) is a thin, coiled tube that lies at the back of each testicle and connects the testicle to another single tube, called the vas deferens.
The vas deferens (vaas def-er-ens) is a muscular tube, about 30 cm long, that connects the epididymis to the urinary tract (urethra) at the back of the bladder. The main job of the vas deferens is to transport mature sperm and semen to the urethra.
The ejaculatory duct is a tube that joins the vas deferens and the seminal vesicle. The ejaculatory duct empties mature sperm and semen into the urethra.
The seminal vesicles (sem-in-al vess-ick-ells) are two small glands that sit directly above your prostate gland, near the base of your bladder. These glands are very active, and create a fluid that makes up more than half of your semen.
The prostate is a small but important gland. The main role of your prostate is to make fluid that protects and gives nutrients to sperm. Your prostate makes about one third of the fluid that is ejaculated from the penis when you orgasm.
Cowper’s glands are a pair of pea-sized glands that sit near your prostate. These glands produce clear mucus that’s released before ejaculation to neutralise any urine that might be left in your urethra. This fluid also acts as a lubricant.
The bladder is a muscular sac that stores urine. The bladder receives urine from the kidneys. When the bladder is full, urine is released into the urethra, the tube that carries the urine out of the body.
The rectum is the final 20 cm strip of the large intestine. Bowel motions (faeces) are stored in the rectum before being passed out during a bowel movement.
Sperm are male reproductive cells that contain the father’s genetic information (DNA) that will be passed onto his children. Each sperm takes about three months to mature. Mature sperm have a tail, allowing them to move inside the female reproductive tract to meet the egg (female reproductive cell).
Semen is the fluid that transports the sperm during ejaculation. During an orgasm, sperm are released from the epididymis, and are mixed with fluid released by the prostate gland and the seminal vesicles. This creates semen. The semen fluid protects and provides nutrients to the sperm.