Prostate gland - definition and function
What is Prostate Gland, Definition and Function
The gland in the male reproductive tract that produces most of the volume of SEMEN. About the shape and size of a walnut, the prostate gland wraps around the URETHRA at the neck of the BLADDER. The back of the prostate gland rests against the front wall of the RECTUM. A tough, fibrous membrane forms a single capsule enclosing the 30 to 50 clusters of glandular tissue that make up the prostate gland. There are three distinct structures of glandular tissue, which urologists refer to as zones—peripheral, transition, and central—though how the zones differ in function remains unknown. The prostate gland also contains nonglandular cells, primarily MUSCLE and connective tissue cells that help move prostatic secretions into the urethra.
Prostate gland cells produce their secretions under stimulation by TESTOSTERONE, which reaches them through the BLOOD circulation. The seminal vesicles, which lie just behind the prostate gland, store mature SPERM encased in a thick, jellylike solution that prevents them from motility. During ORGASM and EJACULATION, the seminal vesicles and the prostate gland each contract, mixing sperm and prostatic fluid in the urethra to form semen. The prostatic fluid contains an enzyme, PROSTATESPECIFIC ANTIGEN (PSA), that thins the semen to allow the sperm to become motile. Ejaculation then carries the semen through the urethra and out the tip of the PENIS.
As a man ages the prostate gland slowly enlarges, a condition called BENIGN PROSTATIC HYPERPLASIA (BPH). In most men BPH remains innocuous, causing no symptoms or even awareness of its presence. Other health conditions that can affect the prostate gland are PROSTATITIS (INFLAMMATION or INFECTION) and PROSTATE CANCER. The surgical OPERATION to remove the prostate gland is PROSTATECTOMY. The doctor can palpate (feel) the prostate gland through the wall of the rectum during DIGITAL RECTAL EXAMINATION (DRE), which helps detect prostate enlargement as well as abnormalities that suggest other health concerns affecting the prostate gland. Because the risk for prostate cancer increases after age 40, DRE palpation of the prostate gland becomes part of the ROUTINE MEDICAL EXAMINATION for men age 40 and older.
| HEALTH CONDITIONS THAT CAN AFFECT THE PROSTATE GLAND | |
|---|---|
| bacterial PROSTATITIS | BENIGN PROSTATIC HYPERPLASIA (BPH) |
| nonbacterial | prostatitis prostadynia |
| PROSTATE CANCER | prostatic ABSCESS |
See also AGING, REPRODUCTIVE AND SEXUAL CHANGES THAT OCCUR WITH; CANCER PREVENTION.
