Prostate, Seminal, and Bulbourethral Glands: Anatomy

Development

• The prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. arises from epithelial buds that emerge from the embryonic urogenital sinus Urogenital Sinus Congenital Malformations of the Female Reproductive System.
• The buds elongate and split, becoming hollow, forming the ducts and acini.
• Interfascicular fibroblasts Fibroblasts Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules. Sarcoidosis and the smooth muscle of the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. arise from the urogenital sinus Urogenital Sinus Congenital Malformations of the Female Reproductive System mesenchyme.
• The prostatic Müllerian mesenchyma further differentiates in response to stimulation with male androgen hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types, forming the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. .

Gross Anatomy

Structure of the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid.

• Lobular fibromuscular gland, covered in a fibrous Fibrous Fibrocystic Change capsule Capsule An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides. Bacteroides, surrounding the prostatic urethra Prostatic urethra from the bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess base to the external urethral sphincter, where the membranous portion of the urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy begins
• Average dimensions: 3 cm long, 4 cm wide, and 2 cm in anteroposterior (AP) depth
• Located in the lesser pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy and lies immediately:
  • Inferior to the bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess
  • Posterior to the pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy
  • Anterior to the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
• Consists of both muscular and glandular tissue:
  • The glandular part makes up approximately ⅔ of the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. ; the other ⅓ is fibromuscular.
  • Glandular tissue can be subdivided into 3 distinct zones, which produce secretions that make up approximately 20% of the seminal fluid.
    • Main prostatic glands: make up the peripheral ⅔ of the gland and empty into the distal urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy
    • Submucosal (outer periurethral) glands: empty into the urethral sinuses
    • Mucosal (inner periurethral) glands: empty directly into the urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy 
• The prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. gland is divided anatomically into 5 lobes:
  • An anterior lobe Anterior lobe Cerebellum: Anatomy ( isthmus Isthmus Uterus, Cervix, and Fallopian Tubes: Anatomy):
    • Located anterior to the urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy
    • Fibromuscular: the muscle fibers that are a superior continuation of the external urethral sphincter to the bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess
    • Contains little, if any, glandular tissue
  • A posterior lobe Posterior lobe Cerebellum: Anatomy:
    • Posterior to urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy
    • Inferior to ejaculatory ducts Ejaculatory Ducts Paired ducts in the human male through which semen is ejaculated into the urethra.
  • 2 lateral lobes: located on either side of the urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy 
  • 1 median Median After arranging the data from loWest to highest, the median is the middle value, separating the lower half from the upper half of the data set. Measures of Central Tendency and Dispersion lobe: cone-shaped portion of the gland situated between the 2 ejaculatory ducts Ejaculatory Ducts Paired ducts in the human male through which semen is ejaculated into the urethra. and the urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy
• The prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. consists of histologically different areas; on this basis, the gland is divided into 4 zones:
  • The central zone:
    • It forms the base of the gland.
    • Encircles the ejaculatory ducts Ejaculatory Ducts Paired ducts in the human male through which semen is ejaculated into the urethra.
    • 25% of glandular tissue
  • The peripheral zone: 
    • Encircles most of the central zone and partially surrounds the distal part of the prostatic urethra Prostatic urethra
    • Most prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. cancers arise from the peripheral zone.
    • 70% of this zone is made up of glandular tissue.
  •  The transition zone Transition Zone Pediatric Gastrointestinal Abnormalities:
    • Encircles the portion of the urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy between the urinary bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess and verumontanum
    • 5% of glandular tissue
  • The anterior fibromuscular stroma:
    • This area has no glandular tissue.
    • Consists of mostly muscular and fibrous Fibrous Fibrocystic Change tissue
• The urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy enters the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. near its anterior border and passes between its anterior and middle thirds.
• The ejaculatory ducts Ejaculatory Ducts Paired ducts in the human male through which semen is ejaculated into the urethra. pass through its posterior region to open into the prostatic urethra Prostatic urethra .

Accessory glandular structures

• Seminal glands Seminal glands A saclike, glandular diverticulum on each ductus deferens in male vertebrates. It is united with the excretory duct and serves for temporary storage of semen. ( vesicles Vesicles Female Genitourinary Examination):
  • Elongated structure, approximately 5 cm long
  • Lies between the fundus Fundus The superior portion of the body of the stomach above the level of the cardiac notch. Stomach: Anatomy of the bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess and the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
  • The duct of the seminal gland joins the ductus deferens Ductus deferens The excretory duct of the testes that carries spermatozoa. It rises from the scrotum and joins the seminal vesicles to form the ejaculatory duct. Testicles: Anatomy to form the ejaculatory duct.
  • Secrete a thick alkaline fluid with fructose (an energy source for sperm)
• Bulbourethral glands Bulbourethral Glands Glands situated on each side of the prostate that secrete a fluid component of the seminal fluid into the urethra. ( Cowper’s glands Cowper’s glands Glands situated on each side of the prostate that secrete a fluid component of the seminal fluid into the urethra. ):
  • Small lobulated structures located immediately posterior and lateral to the membranous urethra Membranous urethra Urinary Tract: Anatomy and superior to the perineal membrane
  • Contraction of muscle fibers leads to the expulsion of clear mucus from the glands during sexual arousal.

Neurovasculature and Lymphatics

Arterial supply

Blood vessels supplying the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. arise from the internal iliac artery and enter the gland from the posterolateral region.

• The iliac artery gives rise to inferior vesical.
• The inferior vesical gives rise to 2 branches:
  • Urethral branch
  • Capsular branch

Venous drainage

• The veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology surrounding the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. join to form the prostatic venous plexus Prostatic venous plexus around the sides and base, which drains into the internal iliac veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology.
• The prostatic venous plexus Prostatic venous plexus is continuous superiorly with the vesical venous plexus.
• The prostatic venous plexus Prostatic venous plexus communicates posteriorly with the internal vertebral venous plexus.

Lymphatic drainage

• Internal iliac lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs nodes
• Sacral lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs nodes

Innervation

• The prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. is innervated by autonomic fibers arising from the inferior hypogastric plexus: 
  • Sympathetic innervation from the hypogastric nerve
  • Parasympathetic innervation via the pelvic splanchnic nerve
• Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation is provided by the hypogastric and pelvic plexuses.
• Urethral sphincter motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology innervation is supplied by somatic pudendal nerve Pudendal nerve A nerve which originates in the sacral spinal cord (s2 to s4) and innervates the perineum, the external genitalia, the external anal sphincter and the external urethral sphincter. It has three major branches: the perineal nerve, inferior anal nerves, and the dorsal nerve of penis or clitoris. Gluteal Region: Anatomy fibers.

Microstructure

The prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. consists of glandular tissue and fibromuscular tissue.

• Glandular epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium: Histology is arranged in acini and ducts lined by:
  • Luminal cells:
    • Columnar, with pale eosinophilic cytoplasm and round nuclei 
    • Secrete into the lumen, contributing to seminal fluid production
    • Strongly positive for PSA PSA A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer. Prostate Cancer immunohistochemistry Immunohistochemistry Histochemical localization of immunoreactive substances using labeled antibodies as reagents. Myeloperoxidase Deficiency
  • Basal cells:
    • Basement membrane Basement membrane A darkly stained mat-like extracellular matrix (ecm) that separates cell layers, such as epithelium from endothelium or a layer of connective tissue. The ecm layer that supports an overlying epithelium or endothelium is called basal lamina. Basement membrane (bm) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. Bm, composed mainly of type IV collagen; glycoprotein laminin; and proteoglycan, provides barriers as well as channels between interacting cell layers. Thin Basement Membrane Nephropathy (TBMN) adjacent
    • Ovoid nuclei and inconspicuous cytoplasm
    • The number of basal cells varies between glands in an individual prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. .
  • Neuroendocrine cells: positive for neuroendocrine markers such as chromogranin and synaptophysin Synaptophysin A marvel domain-containing protein found in the presynaptic vesicles of neurons and neuroendocrine cells. It is commonly used as an immunocytochemical marker for neuroendocrine differentiation. Gastrinoma
• Prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. secretions (along with seminal vesicular secretions) form the bulk of the seminal fluid. Acidic secretions are composed of:
  • Proteolytic enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes
  • Acid phosphatase
  • PSA PSA A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer. Prostate Cancer
  • Fibrinolysin Fibrinolysin A product of the lysis of plasminogen (profibrinolysin) by plasminogen activators. It is composed of two polypeptide chains, light (b) and heavy (a), with a molecular weight of 75, 000. It is the major proteolytic enzyme involved in blood clot retraction or the lysis of fibrin and quickly inactivated by antiplasmins. Hemostasis
  • Zn

Clinical Relevance

• Benign Benign Fibroadenoma prostatic hyperplasia Hyperplasia An increase in the number of cells in a tissue or organ without tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. Cellular Adaptation ( BPH BPH Benign prostatic hyperplasia (bph) is a condition indicating an increase in the number of stromal and epithelial cells within the prostate gland (transition zone). Benign prostatic hyperplasia is common in men > 50 years of age and may greatly affect their quality of life. Benign Prostatic Hyperplasia): a common condition in older men (> 50) characterized by a firm enlargement of the lateral and middle lobes. The growth is not premalignant and presents low levels of clinical risk. The most important symptoms include increased frequency of urination and slowness or dribbling of the urinary stream. Benign Benign Fibroadenoma prostatic hyperplasia Hyperplasia An increase in the number of cells in a tissue or organ without tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. Cellular Adaptation is detected via both blood PSA PSA A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer. Prostate Cancer test and digital rectal exam ( DRE DRE A physical examination in which the qualified health care worker inserts a lubricated, gloved finger of one hand into the rectum and may use the other hand to press on the lower abdomen or pelvic area to palpate for abnormalities in the lower rectum, and nearby organs or tissues. The method is commonly used to check the lower rectum, the prostate gland in men, and the uterus and ovaries in women. Prostate Cancer Screening). Various treatment options are available, including surgical and supportive.
• Prostate cancer Prostate cancer Prostate cancer is one of the most common cancers affecting men. In the United States, the lifetime risk of being diagnosed with prostate cancer is approximately 11%, and the lifetime risk of death is 2.5%. Prostate cancer is a slow-growing cancer that takes years, or even decades, to develop into advanced disease. Prostate Cancer: among the most common cancers in men worldwide. Prostate cancer Prostate cancer Prostate cancer is one of the most common cancers affecting men. In the United States, the lifetime risk of being diagnosed with prostate cancer is approximately 11%, and the lifetime risk of death is 2.5%. Prostate cancer is a slow-growing cancer that takes years, or even decades, to develop into advanced disease. Prostate Cancer may cause no signs or symptoms in its early stages. Uncommonly, the cancer may present with nonspecific urinary symptoms, hematuria Hematuria Presence of blood in the urine. Renal Cell Carcinoma, or hematospermia. Diagnosis is based on PSA PSA A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer. Prostate Cancer testing and DRE DRE A physical examination in which the qualified health care worker inserts a lubricated, gloved finger of one hand into the rectum and may use the other hand to press on the lower abdomen or pelvic area to palpate for abnormalities in the lower rectum, and nearby organs or tissues. The method is commonly used to check the lower rectum, the prostate gland in men, and the uterus and ovaries in women. Prostate Cancer Screening. A variety of treatment options are available, including surgery, chemotherapy Chemotherapy Osteosarcoma, and radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma. The overall 5-year survival rate is over 98%.
• Prostatitis Prostatitis Prostatitis is inflammation or an irritative condition of the prostate that presents as different syndromes: acute bacterial, chronic bacterial, chronic prostatitis/chronic pelvic pain, and asymptomatic. Bacterial prostatitis is easier to identify clinically and the management (antibiotics) is better established. Prostatitis: a term that indicates inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. , which can be due to infectious Infectious Febrile Infant or noninfectious Noninfectious Febrile Infant causes. Bacterial prostatitis Prostatitis Prostatitis is inflammation or an irritative condition of the prostate that presents as different syndromes: acute bacterial, chronic bacterial, chronic prostatitis/chronic pelvic pain, and asymptomatic. Bacterial prostatitis is easier to identify clinically and the management (antibiotics) is better established. Prostatitis is easier to identify clinically and its management is better established. The main diagnostic tools for prostatitis Prostatitis Prostatitis is inflammation or an irritative condition of the prostate that presents as different syndromes: acute bacterial, chronic bacterial, chronic prostatitis/chronic pelvic pain, and asymptomatic. Bacterial prostatitis is easier to identify clinically and the management (antibiotics) is better established. Prostatitis are clinical history and physical exam. Prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. massage by DRE DRE A physical examination in which the qualified health care worker inserts a lubricated, gloved finger of one hand into the rectum and may use the other hand to press on the lower abdomen or pelvic area to palpate for abnormalities in the lower rectum, and nearby organs or tissues. The method is commonly used to check the lower rectum, the prostate gland in men, and the uterus and ovaries in women. Prostate Cancer Screening is only recommended in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with chronic prostatitis Prostatitis Prostatitis is inflammation or an irritative condition of the prostate that presents as different syndromes: acute bacterial, chronic bacterial, chronic prostatitis/chronic pelvic pain, and asymptomatic. Bacterial prostatitis is easier to identify clinically and the management (antibiotics) is better established. Prostatitis and not for acute bacterial prostatitis Acute bacterial prostatitis Acute bacterial infection of the prostate with lower urinary tract symptoms Prostatitis.