What Is the Prostate? A Guide to Its Form and Function and Some Common Problems
The prostate gland, an organ in the male body, produces a fluid that makes up an important part of semen and is therefore vital for reproduction.
The prostate is a gland and reproductive organ located directly beneath the urinary bladder.
About the size and shape of a walnut, the prostate is only found in males and is an important part of the male reproductive system. (1)
Note that although females do not have a prostate, they do have the Skene's?gland, or paraurethral gland, which is located at the lower end of the urethra and considered homologous to the prostate gland. (2)
Numerous health issues may affect the prostate as men get older, including prostatitis (prostate inflammation), prostate infections, enlarged prostate, and prostate cancer. (1)
Where Is the Prostate and What Does It Look Like?
The prostate is situated between the bladder and penis, just in front of the rectum (lower end of the bowel). It is above the muscles of the pelvic floor.
The urethra, a narrow tube that carries urine and semen out of the body through the penis, runs through the center of the prostate, which weighs less than 1 ounce (20 to 30 grams).
The word "prostate" comes from the Greek word "prostates," which means "one who stands before," aptly describing the position of the gland. That is, when viewed from below, the prostate "stands before" the bladder.
Because the rectum is behind the prostate, it is possible to feel the prostate with a finger when inserted through the rectum. The prostate feels elastic because it's surrounded by a supportive tissue called the stroma, which is made of flexible smooth muscle fibers and connective tissue (the prostate itself also contains many smooth muscle cells).
What Does the Prostate Gland Actually Do?
The prostate gland isn't essential for life, but it is vital for reproduction and is part of the male reproductive system.
The rest of semen is composed of sperm cells from the testicles, fluid from the seminal vesicles, and secretions from the pea-sized bulbourethral gland.
The prostatic fluid contains substances that are important to the functioning and survival of sperm cells, such as the enzyme?prostate-specific antigen (PSA), which thins or loosens up semen, helping the tadpole-like sperm cells swim freely to reach the egg.
Other important components of prostatic fluid include an enzyme called prostatic acid phosphatase, citric acid, zinc, spermine (which plays a vital role in cellular metabolism) and prostatic inhibin (a protein involved in cell growth regulation). (5)
During an orgasm, prostate muscles squeeze the gland's stored fluid into the urethra, where it mixes with the sperm cells and other semen components.
This expulsive process also helps propel the semen out of the body during ejaculation. (3)
How Is the Prostate Involved in Reproduction?
The prostatic fluid accounts for 20 to 30 percent of the volume of seminal fluid (semen). (2)
As mentioned before, this fluid contains enzymes, proteins, and minerals that protect and nourish sperm —?and are necessary for the proper functioning of sperm cells.
What's more, research, such as one paper published in July 2015 in the journal?PloS?One, has suggested the alkalinity (or basic pH level) of the fluid helps ensure the viability of sperm in reproduction. (6)
The prostatic fluid mixes with sperm and fluid from the seminal vesicles —?which makes up the majority of semen and contains various other components, including the fructose that provides the main energy source for sperm outside of the body?— inside of the urethra. (7)
Changes in the composition or secretion of the prostatic fluid affects the health and function of sperm, impacting male fertility.(5) These changes may arise due to various health issues with the prostate.
Prostatitis: A Common Prostate Problem in Younger Men
Prostatitis, or prostate inflammation, is the most common prostatic and urinary tract problem for men under age 50, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). It accounts for 2 million doctor visits in the United States each year. (8)
There are several types of prostatitis.
Prostatitis caused by bacteria is known as bacterial prostatitis, and it can cause an acute (short term) or chronic infection.
Nonbacteria microbes may cause a different type of chronic prostatitis, known as chronic pelvic pain syndrome, which may also develop as a result of chemicals in the urine, a?urinary tract infection, or pelvic nerve damage.
Affecting 10 to 15 percent of the U.S. male population, chronic pelvic pain syndrome is the most common type of prostatitis,?but also the least understood.
Symptoms vary depending on the type of prostatitis, but can include urination problems, pain (from the perineum to the penis and scrotum to the central lower abdomen and lower back), fever, and body aches, among other things.
Some people develop asymptomatic inflammatory prostatitis, in which the prostate is inflamed but doesn't produce any symptoms or require treatment.
Bacterial prostatitis is most often treated with antibiotics. Chronic pelvic pain syndrome may require drugs, surgery, and lifestyle changes.
Over time, prostatitis may cause sexual dysfunction, abscesses in the prostate, inflammation of nearby reproductive organs, and infection of the bloodstream. (8,9)
Another Common Issue: Enlarged Prostate or Benign Prostatic Hyperplasia
Noncancerous prostate enlargement is the most common prostate problem for men over 50 years old, according to the NIDDK. (10)
It's not well understood what causes prostate enlargement, also known as?benign prostatic hyperplasia (BPH), but research suggests age-related hormonal changes may be to blame. Men younger than 40 rarely experience symptoms of BPH.
In men with BPH, the prostate presses into and pinches the urethra as it enlarges.
This pressure can negatively affect the urine-holding bladder, which is connected to the urethra, by weakening it and preventing it from emptying completely.
Prostate enlargement can cause a number of related urination symptoms, such as:
- Increased urinary frequency and urgency
- Weak or interrupted urine stream
- Urine with an unusual color or smell
- Nocturia, or frequent urination during periods of sleep
- Pain after urination (or after ejaculation)
Over time, BPH may cause complications, including urinary tract infections, damage to the bladder or kidneys, and bladder stones, among other things.
Treatment of BPH includes lifestyle changes, medication, and surgery, which may be minimally invasive. (10,11)
Prostate Cancer: Risk Factors, Symptoms, and Treatment
Aside from prostatitis and BPH, another common prostate issue is?prostate cancer.
Excluding?skin cancer, prostate cancer is the most common type of cancer among?American men, according to the American Cancer Society. About 1 in 9 men will be diagnosed with prostate cancer during his lifetime.
The risk of developing prostate cancer is higher for men who are over age 65, are African-American, or have a family history of the disease. (12)
Most often, prostate cancer develops slowly, but some men develop an aggressive form of the disease.
Early prostate cancer generally doesn't cause any symptoms. Symptoms generally develop as the disease progresses and include:
- Urination issues
- Erectile dysfunction
- Bloody semen
- Bone pain (particularly the hips, spine, and ribs)
- Numbness of the legs and feet
- Loss of bladder or bowel control
But most of these symptoms can also be caused by other problems.
Primary treatment options include surgery, radiation therapy, and hormone therapy.
Prostate cancer has a high 5- to 15-year survival rate, though the disease can often be deadly if it spreads to distant lymph nodes, bones, or other organs. It is still the second leading cause of cancer death in American men (behind lung cancer).(12,13)
Resources and Support for Maintaining a Healthy Prostate
If you’re having prostate trouble, you’re concerned about a friend or family member who is, or you’d like to stay up to date on prostate health and research, there are a number of organizations that provide online educational material, comprehensive medical information, emotional support, and avenues for financial assistance.