The prostate gland 101

The prostate gland is a walnut-sized gland in men located directly beneath the bladder, which produces prostatic fluid (the liquid part of semen)

•    This male gland (really glandular tissue)  envelops the urethra (carries urine from bladder to penis) and its thousands of glands secrete prostatic fluid to nourish and transport semen   - especially during sexual arousal

•     Size of a small kiwi fruit -weighs 20 -25 grams (2/3 to 3/4 of an ounce), but can weigh > 10 oz.

•     Divided into 2 lobes

•        Contains smooth muscle cells and connective tissue ("stroma") -muscles can contract to expel prostatic fluid 

•        Divided into 3 zones

•        Central zone -involved with connection of seminal vesicles to prostate

•        Transitional zone -located between central and peripheral zones; the exclusive site of BPH

•        Peripheral zone -felt during a rectal examination; the most common site of cancer

Semen / Seminal Fluid

Right and left seminal vesicles attach to the prostate secrete seminal fluid - which drains into the prostate and urethra via the ejaculatory ducts. 

Semen is alkaline - to  help neutralize acidity in vaginal tract

SEMEN (ejaculated during orgasm) is formed from:

•    Prostatic Fluid (25-30% / from prostate) -during ejaculation, muscular contractions squeeze prostatic fluid into urethra (whose other function is to carry urine from bladder out through penis)

•    Seminal fluid (65-75% /from seminal vesicles) -excretory duct of each of two seminal glands (located in pelvis) opens into the vas deferens to enter the part of urethra passing through the prostate gland; high in fructose, it can provide food for the sperm on their journey

•    Sperm (2-5%  / from testes) - travel via the vas deferens from testes to join with the seminal vesicle to form the ejaculatory duct, which passes through the prostate and empties into the urethra. Rhythmic muscle movements propel sperm forward  during ejaculation. After a vasectomy, ejaculate no longer contains sperm.

•    Bulbourethral fluid (<1% / bulbourethral glands) -its cohesive jelly-like texture "hangs on to"sperm and lessens semen viscosity  allowing them to swim in it more easily