Exam 2 Flashcards
Scientific Knowledge Base – Urinary System
Kidney
Retroperitoneal
Located against the posterior abdominal wall behind the peritoneum
Weighs about 5 ounces and is the shape of a kidney bean.
The nephron is the basic structural and functional unit of the kidney.
The nephrons form urine.
Each nephron consists of:
A Bowman’s capsule (a double-walled hollow capsule), enclosing a glomerulus (a knotty ball of capillaries)
A series of filtrating tubules
A collecting duct
Function of the kidneys
Filter:
Metabolic wastes, toxins, excess ions, water from the blood and excrete them as urine
Regulate
Blood volume, blood pressure, electrolyte levels, and acid–base balance by selectively reabsorbing water and other substances
Produce erythropoietin
Secrete the enzyme renin
Activate vitamin D3
Ureters transport urine
From kidney to bladder
Peristaltic waves
Bladder stores urine
Detrusor muscle
Urethra transports urine
From bladder to urethral meatus
Urination
AKA voiding, micturition
Bladder emptying
Urinary Process
Filling of bladder (200 to 450 mL of urine)
Activation of stretch receptors in bladder wall
Signaling to the voiding reflex center
Contraction of detrusor muscle
Conscious relaxation of external urethral sphincter
Factors influencing urinary elimination
Growth and Development
-Infants
15 to 60 mL per kg
Produce 8 to 10 wet diapers/day
No voluntary control until 18-24 mos.
Factors influencing urinary elimination
Children
-Toilet training requires
Mature neuromuscular system
Adequate communication skills
-Problems include
Enuresis
Nocturnal enuresis
Typically resolves by 3-5y
Life Span Considerations Related to Urination
-Most adults void 5-6/day
After awakening
After meal
At hs
-Kidneys produce 50-60 mL/ hr
Infrequent voiding … ? Dehydration
Frequent voiding … ? UTI, ? DM
Life Span Considerations Related to Urination
-Older adults
+Kidney function decreases
+Loss of elasticity in bladder wall
Urgency and frequency common
+Loss of bladder elasticity and muscle tone leads to
Stress incontinence
+Prostate enlargement
Nocturia
Incomplete emptying
+Cognitive changes
Factors Affecting urinary Elimination
-Personal
Loss of dignity
Need for privacy and time
Factors Affecting urinary Elimination
-Sociocultural
Cultural and gender norms vary
Who can assist
Factors Affecting urinary Elimination
-Environmental
Private facilities vs. communal
Factors Affecting urinary Elimination
-Nutrition/Hydration
Fluid intake and fluid balance
Use of caffeine, ETOH, Sodium
