The male reproductive system includes a group of organs that make up a man’s reproductive and urinary system. These organs do the following jobs within your body:
. They produce, maintain and transport sperm (the male reproductive cells) and semen (the protective fluid around sperm).
. They discharge sperm into the female reproductive tract.
. They produce and secrete male sex hormones.
The male reproductive system is made up of internal (inside your body) and external (outside your body) parts. Together, these organs help you urinate (rid your body of liquid waste materials), have sexual intercourse and make children.
The entire male reproductive system is dependent on hormones. These are chemicals that stimulate or regulate the activity of your cells or organs. The primary hormones involved in the functioning of the male reproductive system are follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone.
FSH and LH are produced by the pituitary gland. It’s located at the base of your brain and it’s responsible for many functions in your body. FSH is necessary for sperm production (spermatogenesis). LH stimulates the production of testosterone, which is necessary to continue the process of spermatogenesis. Testosterone is also important in the development of male characteristics, including muscle mass and strength, fat distribution, bone mass and sex drive.
Most of the male reproductive system is located outside of your abdominal cavity or pelvis. The external parts of the male reproductive system include the penis, the scrotum and the testicles.
The penis is the male organ for sexual intercourse. It has three parts:
. The root: This is the part of the penis that attaches to the wall of your abdomen.
. The body or shaft: Shaped like a tube or cylinder, the body of the penis is made up of three internal chambers. Inside these chambers there’s a special, sponge-like erectile tissue that contains thousands of large spaces that fill with blood when you’re sexually aroused. As the penis fills with blood, it becomes rigid and erect, which allows for penetration during sex. The skin of the penis is loose and elastic, allowing for changes in penis size during an erection.
. The glans: This is the cone-shaped end of the penis. The glans, which is also called the head of the penis, is covered with a loose layer of skin called foreskin. This skin is sometimes removed in a procedure called circumcision.
The opening of the urethra — the tube that transports both semen and urine out of the body — is located at the tip of the glans penis. The penis also contains many sensitive nerve endings.
Semen, which contains sperm, is expelled (ejaculated) through the end of the penis when a man reaches sexual climax (orgasm). When the penis is erect, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm.
The scrotum is the loose pouch-like sac of skin that hangs behind the penis. It holds the testicles (also called testes), as well as many nerves and blood vessels. The scrotum protects your testes, as well as providing a sort of climate control system. For normal sperm development, the testes must be at a temperature slightly cooler than the body temperature. Special muscles in the wall of the scrotum allow it to contract (tighten) and relax, moving the testicles closer to the body for warmth and protection or farther away from the body to cool the temperature.
The testes are oval organs about the size of very large olives that lie in the scrotum, secured at either end by a structure called the spermatic cord. Most men have two testes. The testes are responsible for making testosterone, the primary male sex hormone, and for producing sperm. Within the testes are coiled masses of tubes called seminiferous tubules. These tubules are responsible for producing the sperm cells through a process called spermatogenesis.
The epididymis is a long, coiled tube that rests on the backside of each testicle. It carries and stores sperm cells that are created in the testes. It’s also the job of the epididymis to bring the sperm to maturity — the sperm that emerge from the testes are immature and incapable of fertilization. During sexual arousal, contractions force the sperm into the vas deferens.
You have several internal organs — also called accessory organs — that play a big part in the male reproductive system. These organs include:
. Vas deferens: The vas deferens is a long, muscular tube that travels from the epididymis into the pelvic cavity, to just behind the bladder. The vas deferens transports mature sperm to the urethra in preparation for ejaculation.
. Ejaculatory ducts: These ducts are formed by the fusion of the vas deferens and the seminal vesicles. The ejaculatory ducts empty into the urethra.
. Urethra: The urethra is the tube that carries urine from the bladder to outside of your body. In males, it has the additional function of expelling (ejaculating) semen when you reach orgasm. When the penis is erect during sex, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm.
. Seminal vesicles: The seminal vesicles are sac-like pouches that attach to the vas deferens near the base of the bladder. The seminal vesicles make a sugar-rich fluid (fructose) that provides sperm with a source of energy and helps with the sperms’ ability to move (motility). The fluid of the seminal vesicles makes up most of the volume of your ejaculatory fluid, or ejaculate.
. Prostate gland: The prostate gland is a walnut-sized structure that’s located below the urinary bladder in front of the rectum. The prostate gland contributes additional fluid to the ejaculate. Prostate fluids also help to nourish the sperm. The urethra, which carries the ejaculate to be expelled during orgasm, runs through the center of the prostate gland.
. Bulbourethral glands: The bulbourethral glands, or Cowper’s glands, are pea-sized structures located on the sides of the urethra, just below the prostate gland. These glands produce a clear, slippery fluid that empties directly into the urethra. This fluid serves to lubricate the urethra and to neutralize any acidity that may be present due to residual drops of urine in the urethra.
Menopause is a term used to describe the end of a woman's normal menstrual function. In women, this is marked by changes in hormone production. One of the biggest changes for a woman after menopause is that she can no longer have children. The testes, unlike the ovaries, don't lose the ability to make hormones. If a man is healthy, he may be able to make sperm well into his 80s or longer.
On the other hand, subtle changes in the function of the testes can happen as early as 45 to 50 years of age, and more dramatically after the age of 70. For many men, hormone production may remain normal into old age, while others may have declining hormone production earlier on. This can sometimes be a result of an illness, such as diabetes.
It’s unclear whether decreasing testicular function contributes to symptoms like fatigue, weakness, depression or impotence.
If your testosterone levels are low, hormone replacement therapy may help relieve symptoms, such as the loss of interest in sex, depression and fatigue. However, replacing male hormones can make prostate cancer worse, and may make atherosclerosis (hardening of the arteries) worse, also.
You should receive a complete physical examination and laboratory tests should be performed before starting hormone replacement therapy. There are still many unanswered questions about how many middle-aged men could benefit from hormone replacement therapy. Talk to your healthcare provider about all the pros and cons of this treatment and what the best option is for you.