Download URINARY SYSTEM

CHAPTER 16
URINARY SYSTEM
Copyright 2003 by Mosby, Inc. All
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Structure and Function
• The functions of the urinary system
are to:
– Filter about 180 liters of blood plasma daily
– Form and excrete urine daily to remove
waste products
– Regulate the chemical composition of body
fluids
– Remove body wastes by filtering blood
Copyright 2003 by Mosby, Inc. All
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Kidneys
• Each kidney is about 4 inches long and 2
inches wide, and weighs about 150 g
• Each kidney contains about 1 to 2 million
nephrons (tiny structures that filter the blood)
• The kidney has three layers
– Cortex
– Medulla
– Renal pelvis
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Figure 16-3 The Kidney
Copyright 2003 by Mosby, Inc. All
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Additional Components of
the Urinary System
• Ureters
– Small tubes composed of smooth muscle tissue,
move the urine from the kidney to the bladder
with peristaltic motion
• Bladder
– A smooth muscular sac that expands as it fills
with urine
• Urethra
– Moves urine from the bladder to be excreted from
the body
Copyright 2003 by Mosby, Inc. All
rights reserved.
Urine Formation
• Every minute blood plasma enters the nephrons of
each kidney through the renal arteries
• In the nephron, particles are filtered from the blood
to be eliminated by the body
• Water, glucose, vitamins, amino acids, and chloride
salts are reabsorbed into the blood in the renal
tubules
• Ammonia, potassium, hydrogen ions, and some drugs
are secreted into the urine
• The blood leaves the kidneys in the renal veins
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Table 16-2 Characteristics of
Urine
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Assessment Techniques
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Urinalysis
Radiological examination (KUB)
Intravenous pyelogram (IVP)
Cystoscopy
Urodynamic tests
Electromyography (EMG)
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Disorders of the Urinary
System
• Cystitis
– Inflammation of the bladder caused by many
different types of bacteria
• Edema
– An abnormal accumulation of fluid in the tissue
intercellular space
• Nephritis
– Inflammation of the kidneys
• Renal calculus
– A kidney stone
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Disorders of the Urinary System
(continued)
• Renal failure
– The absence of urine formation
• Uremia
– A condition in which the kidneys do not filter the
blood
• Urethritis
– Acute or chronic inflammation of the urethra
• Urinary incontinence
– The inability to control urination
Copyright 2003 by Mosby, Inc. All
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Disorders of the Urinary System
(continued)
• Urinary retention
– The inability to urinate when the urge is felt or the
bladder is full
• Urinary tract infection
– Usually caused by bacteria, and may affect the
bladder, kidneys, or prostate
Copyright 2003 by Mosby, Inc. All
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Issues and Innovations
• Dialysis
– Filtration of body fluids through a machine instead
of the kidneys
• Kidney transplant
– Drawbacks include matching tissues, expense, and
shortage of donors
– High success rate
• Lithotripsy
– Disintegrates kidney stones
– Prevents need for surgery to remove stone
Copyright 2003 by Mosby, Inc. All
rights reserved.