DISEASES

Prostate Gland

Author: Dr. Lee
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Time: 2014/4/15 11:22:45

If you don't know what your prostate is or what it does, you're certainly not alone: most men don't. But you really should. More than 30 million men suffer from prostate conditions that negatively affect their quality of life.


1. The structure of the prostate gland


The prostate gland is made up of glandular tissue and muscular tissue. The prostate is part of a man's reproductive system. The prostate gland is the size of a walnut.The transverse diameter of the prostate's extremitas posterior is about four centimeters, and the vertical diameter is about three centimeters, and anteroposterior diameter is about two centimeters. The prostate is surrounded by a thin layer of connective tissue that merges with surrounding soft tissues, which is called prostatic vesicle. There is veniplex between the prostate gland and prostatic vesicle. The prostate gland makes almost a third of the fluid in the semen that a man ejaculates.


The prostate gland wraps around male urethra just below the urinary bladder. A pair of ejaculatory ducts pass through the prostate, and empty into the urethra at the Colliculus seminalis. During ejaculation, semen passes through the ducts and exits the body via the penis. Generally, the prostate gland is made up of five lobes: anterior lobe, median lobe, posterior lobe and the two lateral lobes. The median lobe is wedge-shaped, locating between urethra and ejaculatory duct. Men over age 40 would have a greater risk of developing an enlarged prostate due to the obese median lobe. The enlarged prostate squeezes the urethra, which slows or stops the flow of urine, making it difficult for men to urinate, resulting in the symptoms such as frequent urination, straining to urinate, a weak urine stream, and a sensation that the bladder has not completely emptied.


As the root of the prostate gland is close to bladder neck, seminal vesicle and the ampullae of seminal duct, once the prostate gland is infected by bacteria, the seminal vesicle will be coinfected, and vesiculitis will also stimulate prostatitis. Therefore, prostatitis often amalgamates with vesiculitis. The prostate gland is found in front of the rectum and in back of the pubis symphysis. The size of a child's prostate gland is rather small, and it increases quickly in latency period. When men are old, it deteriorates and atrophies. For instance, the connective tissue inside the gland proliferates, leading to enlarged prostate.


There is a thin layer of envelope on the surface of the prostate gland. This envelope has many elastic fibers and smooth muscles which pass through the gland. Actually, the prostate gland is made up of 30-50 compound tubularacinous glands, and there are 15-30 ducts ending in the sides of colliculus urethralis of urethra. According to their distribution, the gland is divided into mucous gland, submucosal gland, and master gland. Acinar epithelium is made up of simple cuboidal, simple columnar epithelium and pseudostratified epithelium, with much interstitial substance. Besides connective tissue, it also has elastic fibers and smooth muscles. The concretion is always found in the acinar cavity, which is the condensed secretion released by epithelium.


The prostatic fluid released by the prostate gland is the essential component of the semen. If the seminal fluid reduce due to prostatitis, the patients would have the lesion of nonliquefaction of the semen and poor activity of the sperm. So, the patients with prostatitis must promptly look for treatment, if not, it will lead to the serious consequence--male infertility.


2.The main physiological functions of the prostate gland:


1) To secrete prostatic fluid


The prostate gland is the biggest accessory genital gland of male, and one of human exocrine glands. It can secrete prostatic fluid, which is the an important component of seminal fluid and plays an important role to maintain the normal function of sperm. The prostatic fluid helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. The reproduction of bacteria in the reproductive tract will produce some hazardous substance to damage the sperms. The bacterial reproduction in the tractus genitalis consumes large quantity of nutriment, which damages sperm's living environment and the sperms will die due to lack of nutrition. The bacteria excrete large quantity of acid substances in the tractus genitalis, which will reduce the PH value of male tractus genitalis, and cause acid intoxication to the sperms. Therefore, the bacterial infection of the prostate may lead to male infertility.


2) To produce nutrition


The prostate gland is rich in 5α-reductase, which can convert testosterone into DHT which is of more physiological activity. DHT plays an important role in the pathogenesis process of the benign prostatic hyperplasia. By blocking the 5α-reductase, the production of DHT would be reduced, thus shrinking the proliferative prostatic tissue.


3) To control urination


The prostate gland surrounds the urethra and is close to the neck of the bladder, forming the wall of the proximal urethra. The circular and smooth muscle fibers surround the prostatic urethra, constituting the urethral sphincter. When the urge to urinate occurs, the contraction of detrusor and the relaxation of the internal sphincter together make smooth urination.


4) To transport semen


A complex system of valves in the prostate, sends the semen into the urethra during ejaculatory process and a prostate muscle called the sphincter seals the bladder, thereby preventing urine entry into the urethra. The inflammation stimulates the prostate will lead to prostatic edema and hypertrophy, dysuria, inability to ejaculate, impotence and premature ejaculation.

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