What is the Prostate?
The prostate is a small walnut sized gland in the male pelvis. It is part of the male genitourinary tract and resides just below the bladder in men. During in utero growth, the prostate forms in response to male androgens such as testosterone. During puberty, (age 12-14) male androgens surge and the prostate reawakens and begins to grow. By early adulthood the prostate has reached its normal size — about that of a walnut or golf ball. In some men, later in life, the prostate continues to grow, sometimes to the size of an orange. This increased growth can produce urinary symptoms in men, such as weak urinary stream, urinary urgency and frequent urination. The prostate is surrounded by important structures including the rectum and nerve bundles that stimulate erections in men. Treatments of prostatic diseases can sometimes impact the function of these adjacent structures. Because of the prostate’s close proximity to the rectum, the prostate can be felt by a physician with a rectal exam.
What Does the Prostate Do?
The prostate gland produces fluid that protects and nourishes the sperm during intercourse. It also produces enzymes, such as PSA (prostate-specific antigen), which help to break down the thick semen, allowing the sperm to better reach the egg. During orgasm, the prostate squeezes and releases its fluid into the urethra. The testicles and seminal vesicles also empty their contents into the prostatic urethra, mixing together and eventually getting expelled out of the tip of the penis in a process called ejaculation.
During normal daily functions, the role of the prostate is less clear. When the bladder fills with urine, it empties through a tube called the urethra. The first part of the urethra travels through the middle of the prostate. Thus, for some men later in life, urinary drainage from the bladder can be obstructed or blocked by an oversized prostate. The decreased urine flow that ensues is not commonly due to prostate cancer growth, but more often is due to non-cancerous overgrowth.
What Can Go Wrong With the Prostate?
Although small, the prostate can result in many problems in men including urinary infection, urinary obstruction and cancer.
The most common source of infections in men over the age of 50 is the urinary tract, including the prostate and bladder. As the prostate enlarges with age it alters the dynamics of urinary drainage in men. This can lead to suboptimal emptying of urine and subsequent infection. Prostatic enlargement and suboptimal urinary emptying can also induce a multitude of urinary symptoms in men, including weak urinary stream and increased urgency and frequency of urination. See Other Prostate Conditions for more information.
Lastly, prostate cancer is the most common non skin cancer in men. In the United States, where screening for prostate cancer is widely utilized, it is the most common cancer diagnosed in men. In Norway, prostate cancer is the second leading cause of cancer death in men, after lung cancer.