Prostate – Tissue and Systems

This article describes the basic form and function of the prostate gland.  By better understanding these things, symptoms from the prostate and a basic understanding of prostate disease will be developed.

The prostate is a gland found only in men.  The prostate sits under the bladder and contains part of the drainage tube of the bladder, the urethra.  The urine is made in the kidneys, passes through ureters and collects in the bladder.  Periodically, the bladder is emptied during urination.  The urine passes from the bladder through the urethra where the first part of it is within the prostate gland.  The normal prostate is about 18 grams and is about 2 x 4 cm.  The prostate gland functions and grows under the direction of male sex hormones (a derivative of testosterone).

Besides housing the passageway for urine exiting the bladder, the prostate serves a key function in reproduction.  The prostate secretes part of the fluid that composes semen.  The prostate fluid has a high pH (i.e. it is alkaline) and this pH helps sperm survive its transport to the female egg for fertilization.

The prostate’s proximity to the bladder, urethra, seminal vesicles and penis help explain many symptoms that might arise from abnormalities of the prostate.  Normal levels of testosterone, and its derivative dihidrotestosterone (aka DHT) are necessary for normal growth and function of the prostate.

The prostate is under the bladder and is also directly in front of the rectum.  This is why the often feared “prostate examination” consists of a digital (i.e. finger) rectal examination feeling in front of the rectum.  A normal prostate feels small and smooth.  It should not feel very large or have hard nodules or lumps on it.  It should not be asymmetric either.

Common problems of the prostate include:

  • Prostate infection (prostatitis)
  • Prostate inflammation (inflamed but not infected)
  • Prostate swelling / enlargement
  • Prostate Cancer

Prostate infection or inflammation may cause pain and tenderness of the prostate gland.  There may be pain or difficulty with urination.  Treatment of prostate infection involves antibiotics similar to those used to treat kidney or bladder infections.

As a man gets older, the prostate enlarges a bit but sometimes it enlarges too much.  This causes several problems but most are related to a complete or partial blockage of the urinary flow and emptying the bladder can be difficult.  Difficulty emptying the bladder causes several characteristics symptoms.  Understanding the function and position of the prostate is key to interpreting these symptoms.Enlargement of the prostate can also cause difficulties with sexual function

Common symptoms of an enlarged prostate include:

  • Incomplete   bladder emptying – after urinating, the man still has urine in the bladder and can go or has to go a short time thereafter
  • Urinary Frequency – having to urinate frequently, usually in small amounts as above
  • Urinary Intermittency –While urinating, having to start and stop the stream frequently.  Often this is involuntary.
  • Urgency – A feeling of sudden intense pressure to urinate.  Often this feeling comes on at night or shortly after having voided.
  • Straining – Normally, it should not take straining, pushing, “bearing down”, or pressure on the bladder to begin urinating.  With prostate swelling, the man will have to strain as if he is having a bowel movement in order to begin urinating.
  • Nocturia – Having to awaken at night to urinate several times is abnormal and may be associated with enlargement of the prostate.

Enlargement of the prostate that is just swelling of the gland is usually from hormonal stimulation.  This type of enlargement is also known as benign prostate hypertrophy (BPH).  Symptoms from enlargement of the prostate are also known collectively as prostatism.

Swelling of the prostate is usually benign (i.e. not cancer), but sometimes the enlargement of the prostate is due to cancer.  Prostate cancer is the most common cancer diagnosed in men in the United States.  Enlargement of the prostate from cancer can cause the same set of problems as listed above from benign prostate enlargement but also has additional problems that can occur as well.  Prostate cancer has the ability to spread and grow outside of the prostate gland.  Spreading of cancer cells outside their “home” or tissue of origin is called metastases.  The main areas a prostate cancer can spread to are the bones, liver and lungs.  Spread to the bones such as the spine can cause pain or back fractures.  Occasionally, the first way a prostate cancer is found is when a man has severe back pain from fractured spinal vertebrae.

With swelling of the prostate gland from a variety of reasons, the bladder drainage can become partially or completely blocked.  This can interfere greatly with normal kidney function.  With partial or near-complete blockage of the bladder drainage, the kidneys are more prone to infection and kidney failure.  The kidneys have difficulty filtering the blood when the outflow pressures are very high.  The kidneys are basically fancy pressure driven filters and if the outflow is blocked this interferes with glomerular filtration.  When urine cannot empty promptly and is stagnant in the bladder this makes it more prone  to infections.  Infections of the bladder can cause pain and burning with urination. Severe multiple bladder or kidney infections can also damage the kidney over time and cause chronic kidney disease or kidney failure.

REFERENCES:

  1. Townsend Jr, CM; Beauchamp RD; Evers BM; Mattox KL. (2008) Townsend: Sabiston Textbook of Surgery, 18thed.  Chapter 77.  New York, NY: Saunders.
  2. Wein, AJ: (2007) Wein: Campbell-Walsh Urology, 9thed.  Chapter 2. Philadelphia, PA: Saunders Elsevier
  3. This article was originally published on September 3, 2012 and last revision and update was 9/4/2015.