Prostate Flashcards
what is the prostate
The prostate is the largest accessory gland in the male reproductive system.
what does the prostate do
It secretes proteolytic enzymes into the semen, which act to break down clotting factors in the ejaculate. This allows the semen to remain in a fluid state, moving throughout the female reproductive tract for potential fertilisation.
what is teh anatomical position of tbhe prostate
The prostate is positioned inferiorly to the neck of the bladder and superiorly to the external urethral sphincter, with the levator ani muscle lying inferolaterally to the gland.
Most importantly, posteriorly to the prostate lies the ampulla of the rectum – this anatomical arrangement is utilised during Digital Rectal Examinations (DRE), allowing physicians to examine the gland.
The proteolytic enzymes leave the prostate via the prostatic ducts. These open into the prostatic portion of the urethra, through 10-12 openings at each side of the seminal colliculus (or verumontanum); secreting the enzymes into the semen immediately before ejaculation.
what is the anatomical
The prostate is commonly described as being the size of a walnut. Roughly two-thirds of the prostate is glandular in structure and the remaining third is fibromuscular. The gland itself is surrounded by a thin fibrous capsule of the prostate. This is not a real capsule; it rather resembles the thin connective tissue known as adventitia in the large blood vessels.
Traditionally, the prostate is divided into anatomical lobes (inferoposterior, inferolateral, superomedial, and anteromedial) by the urethra and the ejaculatory ducts as they pass through the organ. However, more important clinically is the histological division of the prostate into three zones (according to McNeal):
Central zone – surrounds the ejaculatory ducts, comprising approximately 25% of normal prostate volume.
The ducts of the glands from the central zone are obliquely emptying in the prostatic urethra, thus being rather immune to urine reflux.
Transitional zone – located centrally and surrounds the urethra, comprising approximately 5-10% of normal prostate volume.
The glands of the transitional zone are those that typically undergo benign hyperplasia (BPH)
Peripheral zone – makes up the main body of the gland (approximately 65%) and is located posteriorly.
The ducts of the glands from the peripheral zone are vertically emptying in the prostatic urethra; that main explain the tendency of these glands to permit urine reflux.
That also explains the high incidence of acute and chronic inflammation found in these compartments, a fact that may be linked to the high incidence of prostate carcinoma at the peripheral zone.
The peripheral zone is mainly the area felt against the rectum on DRE, which is of irreplaceable value.
The fibromuscular stroma (or fourth zone for some) is situated anteriorly in the gland. It merges with the tissue of the urogenital diaphragm. This part of the gland is actually the result of interaction of the prostate gland budding around the urethra during prostate embryogenesis and the common horseshoe-like muscle precursor of the smooth and striated muscle that will eventually form the internal and external urethra sphincter.
what are the neoourovasular bundles of the prostate
The prostate is flanked by the two neurovascular bundles that travel through the pelvic floor towards the penis, supplying it with nerve fibres and blood vessels for the corpora cavernosa. The integrity of these bundles is critical for normal erection.
During surgery for prostate cancer (radical prostatectomy), damage is often inevitable to one or both of these bundles, resulting in impairment of erectile function. Special nerve-sparing techniques may prevent extensive damage to these bundles, thus allowing for post-operative potency.
