The main function of the prostate is to store
and secrete a slightly alkaline (pH 7.29) fluid, milky or white of egg
in appearance, that usually constitutes 25-30% of the volume of the
semen along with spermatozoa and seminal vesicle fluid. The alkalinity
of prostate fluid helps neutralize the acidity of the vaginal tract,
prolonging the lifespan of sperm. The prostatic fluid is expelled in
the first ejaculate fractions together with most of the spermatozoa. In
comparison with the few spermatozoa expelled together with mainly
seminal vesicular fluid, those expelled in prostatic fluid have better
motility, longer survival and better protection of the genetic material
(DNA).
The prostate also contains some smooth muscles that help expel semen
during ejaculation.
Regulation
To work properly, the prostate needs male hormones (androgens), which
are responsible for male sex characteristics.
The main male hormone is testosterone, which is produced mainly by the
testicles. Some male hormones are produced in small amounts by the
adrenal glands. However, it is dihydrotestosterone that regulates the
prostate.
Development
The prostatic part of the urethra develops from the pelvic (middle)
part of the urogenital sinus (endodermal origin). Endodermal outgrowths
arise from the prostatic part of the urethra and grow into the
surrounding mesenchyme. The glandular epithelium of the prostate
differentiates from these endodermal cells, and the associated
mesenchyme differentiates into the dense stroma and the smooth muscle
of the prostate. [3]The prostate glands represent the modified wall of
the proximal portion of the male urethra and arises by the 9th week of
embryonic life in the development of the reproductive system.
Condensation of mesenchyme, urethra and Wolffian ducts gives rise to
the adult prostate gland, a composite organ made up of several
glandular and non-glandular components tightly fused within a common
capsule.
Skene's glands found in many females are homologous to the prostate
gland in males.
Structure
A healthy human prostate is slightly larger than a walnut. It surrounds
the urethra just below the urinary bladder and can be felt during a
rectal exam.
The ducts are lined with transitional epithelium.
Within the prostate, the urethra coming from the bladder is called the
prostatic urethra and merges with the two ejaculatory ducts. (The male
urethra has two functions: to carry urine from the bladder during
urination and to carry semen during ejaculation.) The prostate is
sheathed in the muscles of the pelvic floor, which contract during the
ejaculatory process.
source: Wikipedia
