1. CHAPTER 16 URINARY SYSTEM
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2. 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 rights reserved.

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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
Copyright 2003 by Mosby, Inc. All rights reserved.

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Figure 16-3 The Kidney
Copyright 2003 by Mosby, Inc. All rights reserved.

5. 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.

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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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7. Table 16-2 Characteristics of Urine
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8. Assessment Techniques
Urinalysis
Radiological examination (KUB)
Intravenous pyelogram (IVP)
Cystoscopy
Urodynamic tests
Electromyography (EMG)
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9. 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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10. 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
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11. 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
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12. 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.