Prostate gland

Watch: Video On Prostate

The prostate is an accessory gland of the male reproductive system. In females the prostate is represented by the paraurethral glands. The Prostatic size changes with age. At birth the prostate is small in size. At puberty, the male hormones bring about rapid changes in the gland. In less than one year the gland size will increase double its prepubertal size.
After 50 years the gland either enlarge causing benign hypertrophy (BPH- enlarge prostate) or reduce in size (senile atrophy)

Functions

  1. The gland produces thin, milky fluid containing citric acid and acid phosphatase which is added to the seminal fluid at the time of ejaculation and adds bulk to the seminal fluid.
  2. The secretion is alkaline and helps to neutralize the acidity in the vagina, which favors sperm survival.


General Features

  • The prostate is inverted cone-shaped, a fibromusculo-glandular organ, measures about 3cm long, located between the neck of the urinary bladder superiorly and the urogenital diaphragm inferiorly
  • The gland is surrounded by a fibrous capsule which is enclosed by a fibrous sheath derived from the pelvic fascia. This fibrous capsule prevents prostate from enlarging outwards. In case of BPH the gland enlarge inwards, compress the urethra and cause urinary obstruction.
  • The gland is traversed by the prostatic urethra. The prostatic ducts open on the sides of the seminal colliculus.
  • The prostate has a base which lies superiorly against the neck of the urinary bladder and an apex which lies inferiorly against the urogenital diaphragm


Structure
Numerous glands embedded in a mixture of smooth muscle and connective tissue are incompletely divided in 5 lobes or zones:

  1. Anterior lobe; anterior to the urethra; fibromuscular; no glandular tissue
  2. Median (middle) lobe; between urethra and ejaculatory ducts; upper surface related to the trigone where it produces an elevation immediately posterior to the internal urethral orifice (uvula of the bladder), rich in glands and more prone for BPH.
  3. Posterior lobe; posterior to the urethra and inferior to the ejaculatory ducts, contains glandular tissue, readily palpable by rectal examination
  4. Lateral lobes; on either side of the urethra, contain many glands


Blood Supply:
Arteries
The branches of the inferior vesical and middle rectal arteries (from internal iliac artery)

Veins:
The veins from the prostate form the prostatic venous plexus between the capsule and fibrous sheath which receives the deep dorsal vein of the penis and the vesical veins and drains into internal iliac veins.
Continuous superiorly with the vesical venous plexus and communicates posteriorly with the internal vertebral venous plexus

Lymphatic Drainage:
Internal iliac and sacral lymph nodes

Nerve Supply:
Parasympathetic fibers arise from the pelvic splanchnic nerves
Sympathetic fibers derive from the inferior hypogastric plexuses stimulate the smooth muscle of the prostate during ejaculation