An Overview of the Male Reproductive System

The male reproductive system consists of internal and external organs that play a role in sexual function, human reproduction, and urination. The sex organs typically referred to as male produce sperm and semen that, during sexual intercourse, can fertilize an ovum (egg) in a female to conceive a baby.

Outside of reproduction, the male reproductive system produces hormones that play a central role in the development of sexual function and characteristics often classified as male. Parts of the reproductive tract also enable urination (the passing of liquid waste from the body).

This article describes the various organs that make up the male reproductive system, including their function and conditions that can adversely affect those functions.

Parts of the Male Reproductive System

The male reproductive system is made up of a complex network of organs both inside and outside of the body. The organs have different structures that enable functions such as urination and ejaculation.

External Structures

The external organs of the male reproductive system consist of the penis and scrotum, both of which are situated at the base of the pelvis.

Penis

The penis is the male organ for sexual intercourse and urination.

It is a complex organ made up of different structures that work in coordination to enable erections (the enlargement and stiffening of the penis during sexual stimulation), ejaculation (the discharge of semen during sexual orgasm), and urination.

Penises come in different sizes and shapes but consist of the following key structures:

• Glans: Also known as the head of the penis, this bulbous, sensitive structure is covered with a loose layer of skin called the foreskin (prepuce). The foreskin is sometimes removed in a surgical procedure known as circumcision.
• Urethra: This is the tube that runs the length of the penis through which semen and urine exit the body. The opening at the head itself is called the meatus.
• Shaft: Also known as the corpus, this section of the penis is made of three columns of spongy tissue, two of which fill with blood to enable erections (called the corpus cavernosa) and the other of which (corpus spongiosum) supports the urethra and keeps it open during erections.
• Root: Also known as the radix penis, this is the base of the penis that is attached to the pelvis and stabilized by connective tissues known as ligaments.

Scrotum

The scrotum is a loose, pouch-like sack of skin situated below the penis that houses the testes ("balls"). The scrotum maintains the ideal temperature for sperm to survive. It does so through nerves within the skin that cause the scrotum to shrink and become wrinkly when it is cold (increasing the temperature) or relax and loosen when it is warm (reducing the temperature).

Internal Organs

The male reproductive system's internal structure consists of organs involved with the production, maintenance, and delivery of sperm (male reproductive cells) and the production and delivery of semen (fluids that transport sperm out of the body).

Other functions include the production and secretion of hormones.

Testes

Testes, also known as the testicles, are two oval organs housed within the scrotum that are suspended by a cable-like structure called the spermatic cord. The testes are responsible for producing sperm and the hormone testosterone.

Within the testes is a network of coiled tubes called seminiferous tubules. These tubules are responsible for producing the sperm through a process called spermatogenesis.

Epididymis

The epididymis is a long, tightly coiled tube situated at the back of each testicle into which sperm is passed from the seminiferous tubules. It is within the epididymis that spermatozoa (sperm cells) will begin to mature until they are capable of fertilization.

Vas Deferens

The vas deferens, also known as the sperm duct, is a long, thin tube that starts at the epididymis and connects to a passageway known as the ejaculatory duct. During orgasm, powerful muscular contractions will propel sperm from the vas deferens, where it will combine with various fluids to form semen.

During a vasectomy, the vas deferens is cut or ligated (closed) to prevent sperm from exiting the testes and epididymis.

Accessory Glands

The accessory glands are organs that secrete fluids that lubricate, nourish, preserve, and transport sperm. Together, they are responsible for producing a substance called seminal fluid that combines with sperm to form semen.

The three organs that make up the accessory glands are:

• Seminal vesicles: These are a pair of glands situated behind the bladder that produces fluids rich in a sugar called fructose (that nourishes sperm) and a substance called prostaglandin that triggers sperm motility (movement).
• Prostate gland: This walnut-sized gland situated below the bladder contains ducts that secrete a fluid called prostatic fluid that creates the ideal environment for sperm to survive.
• Bulbourethral glands: Also known as the Cowper's glands, these organs secrete fluids that help neutralize the acidity of the female vagina while providing lubrication at the tip of the penis in the form of preseminal fluid ("pre-cum").

How Does the Male Reproductive System Function?

Sex hormones regulate the male reproductive system. These include androgens and estrogens. People of all sexes produce these hormones, although males usually produce more androgens, and females usually produce more estrogens.

The primary sex hormone in males is an androgen known as testosterone. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) help regulate testosterone as well as the production and maturation of sperm cells.

Both FSH and LH are produced by the pea-sized pituitary gland located at the base of the brain. FSH and androgens work together to stimulate and maintain spermatogenesis. LH directly stimulates the testes to make more testosterone.

These hormonal interactions are essential to numerous biological and physiological functions in males, including:

• Puberty and secondary sexual characteristics: This includes the development of facial hair, an enlarged Adam's apple, the deepening of the voice, and increased stature and muscle mass.
• Sexual function: This includes libido (sex drive), erection, and ejaculation.
• Fertility and reproduction: This includes sperm count and sperm viability.

Urination is the one function of the male reproductive system not linked to reproduction or sexual function. The expulsion of urine through the penis is regulated by voluntary and involuntary sphincter muscles, the latter of which prevents urine from entering the urethra during ejaculation.

Conditions and Disorders

There are many conditions and disorders that can affect the function of the male reproductive system. Some are influenced by age (due to normal declines in testosterone and other factors), while others can affect males of any age.

Delayed Ejaculation

Delayed ejaculation is the inability to achieve orgasm (sexual climax) despite sexual desire and stimulation. Causes include low testosterone, nerve damage (including diabetic neuropathy), alcohol, certain medications, depression, and stress.

The inability to climax is known as anorgasmia.

Enlarged Prostate

An enlarged prostate, also known as benign prostatic hyperplasia (BPH), is a condition common in older males that can impede the flow of urine. Symptoms include difficulty urinating, frequent urination, urinary urgency (the need to urinate immediately), and nocturia (frequent nighttime urination).

Epididymitis

Epididymitis is the inflammation of the epididymis. It is most commonly caused by bacterial infections, including sexually transmitted infections (STIs) like chlamydia or gonorrhea.

Epididymis typically affects one testicle. Symptoms include pain, swelling, frequent urination, painful urination, pain with intercourse, or blood in semen.

Erectile Dysfunction

Erectile dysfunction (ED) is the inability to achieve or sustain an erection suitable for sexual intercourse.

The risk of ED increases with age. Other risk factors include obesity, smoking, high blood pressure, pelvic surgery (including prostate surgery), nerve damage, depression, stress, and certain medications.

Hypogonadism

Hypogonadism is the term used to describe abnormally low testosterone levels caused by the dysfunction of the testes. This can lead to low libido, erectile dysfunction, fatigue, muscle loss, depression, and weight gain.

Common causes include an undescended testicle, testicular surgery or radiation, liver disease, kidney disease, HIV, and certain genetic disorders (such as Turner syndrome).

Hypospadias

Hypospadias is a congenital (present at birth) condition in which the opening of the urethra is not at the tip of the penis. The opening instead will be near the head, in the middle of the shaft, or at the junction of the penis and scrotum.

Hypospadias is one of the most common anatomical congenital conditions in babies identified as male. It typically requires corrective surgery by a specialist pediatric surgeon.

Micropenis

Micropenis describes an adult penis that is smaller than 2.8 inches (7 centimeters) when erect. While having a penis of this size won't necessarily interfere with sexual satisfaction, it can sometimes make conceiving a baby difficult and require the assistance of a fertility specialist.

Peyronie's Disease

Peyronie's disease (PD) is the development of scar tissue inside the penis that causes curved, painful erections. PD is typically caused by repeat penile trauma during sex or physical activity. It results from a wound-healing disorder of the tunica albuginea (outer layer of the penile blood bodies) in some people who are susceptible to this condition.

When the bend is significant, it can cause pain during intercourse, interfere with sexual function, and increase the likelihood of erectile dysfunction. The risk of PD increases with age.

Phimosis and Paraphimosis

Phimosis is a condition in uncircumcised males in which a tight foreskin cannot be pulled back over the head of the penis, increasing the risk of penile infection (balanitis).

Paraphimosis is a related condition in which the foreskin is trapped behind the head of the penis, obstructing the flow of blood. Paraphimosis is a medical emergency that can lead to tissue death and gangrene if not treated immediately.

Priapism

Priapism is an erection that lasts for four or more hours, usually without sexual arousal. It is an unwanted condition that can cause increasing pain and lead to permanent nerve damage and erectile dysfunction if not treated promptly.

Causes include certain medications (including erectile dysfunction drugs), spinal cord or genital injury, sickle cell disease (a genetic condition affecting the red blood cells), and certain cancers.

Testicular Torsion

Testicular torsion is a medical emergency that occurs when a testicle rotates excessively, twisting the spermatic cord and cutting off the blood supply. This can lead to sudden and often severe pain with swelling.

If not treated immediately, testicular torsion can lead to permanent damage and the loss of the testicle.

Varicocele

Varicocele is the development of enlarged varicose veins within the scrotum. It usually occurs when there is severe compression of a vein and/or the valves in a vein fail to function.

Varicocele can cause swelling and the formation of a painless lump on a testicle. The impaired blood flow can, in turn, lead to low sperm production, decreased sperm quality, lower testosterone, and infertility.

Cancer

There are several cancers that can directly or indirectly affect the function of the male reproductive organs, including prostate cancer, testicular cancer, penile cancer, colorectal cancer, and anal cancer.

Some of the treatments used to treat these cancers—including prostatectomy (prostate removal) and rectal radiation—can lead to erectile dysfunction or the loss of urinary control.

Maintaining a Healthy Reproductive System

It is not uncommon to experience problems with the male reproductive system, particularly as you get older. Even so, there are a few simple things you can do be improve the overall health of your reproductive tract at any age.

Practice Good Hygiene

You can reduce the risk of balanitis and urinary tract infections (UTIs) by regularly washing the penis and genitals with soap and warm water.

This is especially true if you are uncircumcised since bacteria can proliferate under the foreskin. Be sure to retract the foreskin gently while bathing and clean and dry the penis thoroughly afterward. Avoid powders, like talcum powder, that can become moisture traps.

Get Tested for STIs

Untreated sexually transmitted infections (STIs) can lead to complications if left untreated, including infertility and an increased risk of HIV. If you are at risk of STIs or believe you may have been infected, speak with your healthcare provider about getting tested.

This is especially true for sexually active men who have sex with men (MSM) for whom annual testing is recommended for chlamydia, gonorrhea, syphilis, and HIV. For MSM at high risk of infection, such as those with HIV or multiple sex partners, more frequent testing may be advised.

Maintain a Healthy Lifestyle

Maintaining a healthy male reproductive system involves every aspect of your health.

Certain conditions like obesity, high blood pressure, and type 2 diabetes are directly linked to erectile dysfunction and an enlarged prostate. To reduce your risk, it is important to exercise regularly, eat a healthy low-fat diet, and achieve and maintain a healthy weight.

It is also important to speak with your healthcare provider if you have trouble managing your diabetes or high blood pressure.

Quitting cigarettes is also important as tobacco smoke contributes to erectile dysfunction, enlarged prostate, and prostate cancer as well as reduced sperm count and quality.

Summary

The male reproductive system is made up of external organs (like the penis and scrotum) and internal organs (like the testes, seminal vesicles, and epididymis) that play a role in human reproduction, sexual development, sexual function, and urination.

Many conditions can impair the function of the male reproductive system. Some are more common in older males (like enlarged prostate, erectile dysfunction, and Peyronie's disease), while others can affect younger and older males (including epididymitis and balanitis),

Good hygiene, the avoidance of sexually transmitted infections, and healthy lifestyle choices (like quitting cigarettes and losing weight) can improve the overall health of the male reproductive system.

A Word From Verywell

There are many conditions affecting the male reproductive system that a primary care provider can treat. Even so, common conditions like erectile dysfunction can sometimes benefit from the expertise of a specialist known as a urologist, particularly if standard treatments fall short.

Urologists are specially trained in diseases of the urinary tract and male reproductive organs. They are usually aware of the latest treatments and may be better equipped to identify and treat uncommon conditions affecting the male reproductive tract.

Don't let embarrassment prevent you from seeking treatment for any condition affecting the male reproductive system. Certain conditions can also be seen during a telehealth visit with a urologist.