Читать книгу Saving Your Sex Life: A Guide for Men With Prostate Cancer - John P. Mulhall - Страница 15

The prostate gland is classically described as a walnut-sized structure that lies behind the pubic bone in the pelvis (see Figure 1, Chapter 1). This analogy is somewhat misleading as the prostate varies dramatically in size, practically being nonexistent in a young child to being very small in the young adult and increasing in size as we age. This increasing size, which we will talk about further later, is predominantly related to hormonal surges that occur. It is a structure known as a gland, which is filled with cells and tissues that produce fluids. Running through the tissue of the prostate are ducts (pretty much in the same way that your home’s air conditioning system has ducts) and the purpose of these ducts is to deliver the prostatic fluid into the urethra.

The prostate lies below the bladder and it surrounds the urethra, which passes from the bladder out through the penis. If you think of an apple that you have just cored, the apple itself is the prostate and the cored portion is the urethra. The prostate gland secretes fluid from many ducts into the urethra. Directly in front of the prostate is the pubic bone, and directly behind it is the rectum. It is important to understand that the pelvis, and particularly the male pelvis, is a relatively tight area with multiple organs and structures in very close communication. The prostate lies directly against the front surface of the rectum, and this is why when a physician places his or her finger in the rectum, the prostate can be easily felt and examined.

The primary function of the prostate is to produce a portion of semen. You will remember from Chapter 1 that semen is a combination of fluids coming from the seminal vesicles, the prostate and the vas deferens. The latter is the structure that transports sperm from the testicle. The seminal vesicles produce the vast majority of the semen, but a significant portion of it is produced by the prostate.The purpose of this prostate fluid is to balance the pH of the semen.The seminal vesicle fluid is predominantly alkaline and the prostatic fluid is predominantly acidic, so there is a balance once these two are mixed together. This balance is critical to the nourishment and protection of sperm as they are being stored and delivered into the vagina during sexual intercourse.The prostate,or more accurately the cells (epithelial cells) in the gland, produce an enzyme called prostate specific antigen (PSA). PSA is a chemical which gets delivered into the blood and is used as a screening test for prostate cancer. PSA has a vital function in semen in that it dissolves the semen clot once it is deposited in the vagina and allows sperm to swim out from the liquid toward the cervix.