Human Anatomy - Kotsan I. Ya. 2009

Urogenital System
Reproductive Organs - Male Reproductive Organs
Prostate Gland

The Prostate Gland (prostata) is an unpaired fibromuscular and glandular organ that secretes a fluid which forms part of the seminal fluid (Fig. 175). It is located in the anteroinferior part of the lesser pelvis, beneath the Urinary Bladder and upon the urogenital Diaphragm. The initial part of the Urethra, along with the right and left ejaculatory ducts, passes through the prostate. In shape, the gland resembles a chestnut, slightly flattened in the anteroposterior direction. The transverse diameter of the gland reaches 4 cm, the vertical (superior-inferior) diameter is 3 cm, and the anteroposterior diameter (thickness) is about 2 cm. The mass of the gland in an adult male is 20–25 g.

The gland features a thickened Base of the prostate (basis prostatae), which faces upward and is adjacent to the base of the urinary bladder, Seminal Vesicles, and ampullae of the Ductus Deferentes, and a pointed apex of the prostate (apex prostatae), which points downward and forward, resting against the urogenital diaphragm. Additionally, four surfaces of the gland are distinguished: anterior, posterior, and two inferolateral (right and left). The anterior surface (facies anterior) faces the Pubic Symphysis and is separated from it by loose Connective Tissue housing a venous plexus. Extending from the prostate to the pubic symphysis are the lateral and median puboprostatic ligaments (ligg. puboprostatica) and the puboprostatic Muscle (musculus puboprostaticus). The posterior surface (facies posterior) of the gland is adjacent to the ampulla of the rectum, separated from it by a thin connective tissue plate known as the rectovesical septum (septum rectovesicale). This proximity to the rectum allows the prostate to be palpated in a living person through the anterior rectal wall. The inferolateral surface (facies inferolateralis) (right and left) faces the levator ani muscle.

The gland consists of two lobes: the right lobe (lobus dexter) and the left lobe (lobus sinister), as well as the ISTHMUS OF THE prostate (isthmus prostatae), often referred to as its middle lobe (lobus medius). In elderly individuals, the middle lobe frequently undergoes hypertrophy (benign prostatic hyperplasia), causing urinary obstruction.

Externally, the prostate is surrounded by fascial layers derived from the pelvic fascia, forming a sheath that encloses not only the prostate itself but also adipose tissue and a rather voluminous prostatic venous plexus (plexus venosus prostaticus). Enclosed within its sheath and firmly fused with the urogenital diaphragm, the prostate is securely anchored to the pelvic floor. Beneath the fascial sheath lies the prostatic capsule (capsula prostatica), which is composed of Cytology/cytology/32.html">Smooth Muscle tissue and a small amount of connective tissue, with a thickness of about 1 mm. From the capsule, bundles of fibers extend into the interior of the gland, forming the septa of the prostate.

The prostate is composed of glandular tissue (substantia glandularis) and muscular tissue (substantia muscularis). The glandular tissue forms the parenchyma (parenchyma) of the organ, which consists of 30–40 small prostatic glands (lobules) (glandulae prostaticae) of an alveolar-tubular Structure. The prostatic glands are located mainly in the posterior and lateral PARTS OF THE organ. They produce a whitish, fluid secretion that becomes part of the semen. This secretion flows through the prostatic ducts (ductuli prostatici) into the urethra. The openings of about 30 prostatic ducts open onto the mucosal surface of the prostatic urethra in the area of the seminal colliculus.

The muscular tissue of the prostate is built of smooth muscle Cells which, together with connective tissue septa, form broad partitions separating the prostatic glands from one another. Since there are few prostatic glands in the anterior part of the organ, this area is predominantly occupied by muscular tissue concentrated around the lumen of the male urethra. This prostatic muscle tissue, merging with the muscle bundles of the bladder neck wall, participates in forming the involuntary sphincter of the male urethra. The contraction of the muscular apparatus during ejaculation facilitates the expulsion of secretion from the prostatic glands.

The prostate is considered the biochemical laboratory of the male body, producing Enzymes that liquefy the ejaculate, as well as substances that influence the viability and motility of spermatozoa, enhancing their activity. Recently, it is also believed that the gland performs an endocrine function by secreting Prostaglandins.

The prostate receives its Blood supply from Branches of the inferior vesical and middle rectal Arteries. Venous blood drains into the prostatic and vesical plexuses and further through the inferior vesical Veins into the internal iliac vein. Lymph from the prostate drains into the internal iliac Lymph Nodes.

The prostate is innervated by the prostatic plexus, which receives sympathetic fibers (from the sympathetic trunks) and parasympathetic fibers (from the pelvic splanchnic nerves) originating from the inferior hypogastric plexus.