Anatomy & Physiology of the Genitourinary System: Functions, Assessment, and Age-Related Changes

Genitourinary System Overview

Objectives of Study

This guide outlines the essential functions of the urinary system, describes age-related changes, differentiates types of urinary incontinence, discusses risks associated with nocturia, reviews prostate gland anatomy and pathology, and details assessment techniques for genitourinary health.

• Functions of the urinary system

• Age-related changes in urinary function

• Types of urinary incontinence

• Nocturia and associated risks

• Prostate gland structure and pathology

• Assessment of genitourinary health

Functions of the Urinary System

Key Roles and Processes

The urinary system maintains homeostasis by regulating fluid balance, waste excretion, and several endocrine functions.

• Regulation of blood pressure: The kidneys secrete renin, activating the Renin-Angiotensin-Aldosterone System (RAAS) to control blood pressure.

• Production of hormones: Kidneys produce calcitriol (active vitamin D) and erythropoietin (stimulates red blood cell production).

• Regulation of blood glucose: Kidneys contribute to gluconeogenesis and glucose reabsorption.

• Excretion of wastes: Metabolic wastes (e.g., urea, creatinine) are filtered and excreted in urine.

• Urine transport and storage: Urine passes from kidneys to bladder via ureters, is stored in the bladder, and expelled via the urethra.

Example: The RAAS system is activated during dehydration to increase blood pressure and conserve sodium.

Urinary Function and the Ageing Process

Age-Related Changes in Urinary Physiology

Urinary function is affected by physiological changes associated with ageing, impacting continence and renal efficiency.

• Bladder issues: Incontinence and urinary retention are common but not inevitable; often linked to comorbidities.

• Antidiuretic hormone (ADH): Night-time ADH production declines, increasing nocturnal urine output.

• Renal function: May increase at night due to reduced metabolic demands.

• Urine concentration: Older adults have reduced ability to concentrate urine, increasing risk of dehydration.

• Drug accumulation: Impaired clearance can lead to toxicity.

• Detrusor muscle changes: Overactivity or impaired contraction leads to urgency and incomplete bladder emptying.

Example: Elderly patients may experience nocturia due to decreased ADH and impaired bladder function.

Types of Urinary Incontinence

Classification and Mechanisms

Urinary incontinence is the involuntary loss of urine, classified by underlying mechanism.

• Stress incontinence: Leakage occurs when increased abdominal pressure (coughing, sneezing, laughing) overcomes weak pelvic floor muscles.

• Urge incontinence (Overactive Bladder, OAB): Detrusor muscle contracts prematurely, causing sudden urge and leakage.

• Functional incontinence: Incontinence due to external factors (e.g., mobility impairment, cognitive dysfunction) rather than urinary tract pathology.

Example: A patient with arthritis may experience functional incontinence due to difficulty reaching the toilet in time.

Nocturia

Definition, Prevalence, and Risks

Nocturia is the need to wake and urinate during the night, common in older adults and associated with increased risk of falls.

• Prevalence: Affects up to 59% of men and 62% of women aged 70+.

• Risks:

  • Rushing to the toilet increases fall risk.

  • Postural hypotension may cause dizziness.

  • Mobility deficits further increase risk.

Example: An elderly patient with nocturia may fall due to dizziness and urgency.

Prostate Gland

Anatomy and Function

The prostate gland is a male accessory reproductive organ with important roles in semen production and urinary flow.

• Location: In front of the rectum, behind the symphysis pubis, surrounding the bladder neck and urethra.

• Ducts: 15–30 ducts open into the urethra.

• Seminal vesicles: Project above the prostate, contribute to seminal fluid.

• Secretions: Fluid rich in fructose and prostaglandins nourishes sperm.

• Cowper's glands: Inferior to prostate, secrete mucus for lubrication.

• Bladder outlet obstruction: Enlarged prostate may impede urine flow in older males.

Example: Benign prostatic hyperplasia (BPH) can cause urinary retention in elderly men.

Prostate Cancer

Pathology, Risk Factors, and Screening

Prostate cancer is the most frequently diagnosed cancer in men, with several known risk factors and variable mortality rates.

• Risk factors:

  • Increasing age

  • Family history

  • Inherited mutations in BRCA1 and BRCA2 genes

  • Ethnic/geographic variation (higher mortality in men of African descent)

  • Diets high in red meat or high-fat dairy

  • Obesity (possible association)

• Screening: Recommendations vary by risk profile; PSA blood test is commonly used.

Example: Men with a family history of prostate cancer should follow early screening protocols.

Assessment of Genitourinary System

Subjective Data Collection

Subjective assessment involves gathering patient-reported symptoms and history.

• Urinary frequency or urgency

• Burning or pain on micturition

• Nocturia

• Hematuria (blood in urine)

• Changes in urine color or odor

• Incontinence or loss of control

• Leakage associated with activities (e.g., sneezing, coughing)

Objective Data Collection

Objective assessment includes physical examination and diagnostic tests.

• Inspection: Assess height/weight ratio, body shape, mobility, hygiene, and demeanor.

• Abdominal/genital inspection: Look for discharge or excoriation.

• Vital signs: Pay attention to temperature and blood pressure.

• Bladder scan: Performed post-void to assess residual urine.

• Urinalysis: Collect and analyze urine samples for abnormalities.

• Fluid balance: Evaluate adequacy of fluid intake.

Reproductive Assessment

Structures of the Genitourinary System

Assessment includes evaluation of both male and female reproductive anatomy.

Female Structures	Male Structures
Vagina	Testis
Cervix	Scrotum
Squamocolumnar junction	Glans penis
Anterior & Posterior fornix	Urethra
Rectouterine pouch	Corona
Uterus	Foreskin
Fallopian tubes	Corpus spongiosum
Labia majora/minora	Corpus cavernosum
Perineum	Symphysis pubis
Vestibule	Ductus deferens
Clitoris	Seminal vesicle
Mons pubis	Rectum
Rectum	Prostate
	Bulbourethral gland

Additional Info: Age-Related Changes in Reproductive System

Infants, Adolescents, and Older Adults

• Infants: External genitalia may be engorged due to maternal estrogen.

• Adolescents: Puberty triggers growth of reproductive tract and secondary sex characteristics via estrogen (female) and testosterone (male).

• Older adults:

  • Females: Menopause leads to uterine and ovarian atrophy, vaginal changes, and decreased pubic hair.

  • Males: Testicular mass and testosterone decrease; prostate enlarges (benign prostatic hyperplasia), sperm count declines.

Health Promotion and Screening

Preventive Measures

• Cervical screening: Women and people with a cervix aged 25–74 years, every 5 years.

• Self-examination: Regular breast and testicular self-exams recommended.

• Prostate screening: PSA blood test for prostate cancer risk.

• HPV vaccination: Recommended for men and women under 26 years.