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lthough the kidneys control the formation of urine,
its storage and periodic elimination depend on the
coordinated activity of the smooth and striated muscle
of the two functional units of the lower urinary tract—
the urinary bladder, which serves as reservoir for urine
storage and the urethra and urethral sphincter, which
function as an outlet for urine elimination. Alterations in
the storage and expulsion functions of the lower urinary
tract can result in urine retention, which has deleteri-
ous effects on ureteral and, ultimately, renal function; or
incontinence, with its accompanying social and hygienic
problems. The discussion in this chapter focuses on the
control of urine elimination, disorders of lower urinary
tract structures and function, lower urinary tract infec-
tions, and bladder cancer.
Control of Urine Elimination
The urinary bladder is a freely movable organ located
retroperitoneally on the pelvic floor, just posterior to the
pubic symphysis. It consists of two main components:
the body in which urine collects, and the bladder neck,
which is a funnel-shaped extension of the body that con-
nects with the urethra.
1,2
In the male, the urethra contin-
ues anteriorly through the penis, with the prostate gland
surrounding the neck of the bladder where it empties
into the urethra. In the female, the bladder is located
anterior to the vagina and uterus.
Urine passes from the kidneys to the bladder through
the ureters. The interior of the bladder has openings for
both the ureters and the urethra. The smooth triangular
area that is bounded by these three openings is called the
trigone
(Fig. 27-1). There are no valves at the ureteral
openings, but as the pressure of the urine in the bladder
rises, the ends of the ureters are compressed against the
bladder wall to prevent the backflow of urine.
A
Disorders of
the Bladder and
Lower Urinary
Tract
27
C h a p t e r
Control of Urine Elimination
Bladder Structure
Neural Control of Bladder Function
Spinal Cord Centers
Pontine Micturition Center
Cortical and Subcortical Centers
Neuromediator Control of Bladder Function
Evaluation of Bladder Function
Disorders of Lower Urinary Tract Structures and
Function
Lower Urinary Tract Obstruction and Stasis
Compensatory and Decompensatory Changes
Neurogenic Bladder Disorders
Neurogenic Overactive Bladder: Failure to
Store Urine
Neurogenic Areflexic Bladder: Failure to
Empty Urine
Nonrelaxing External Sphincter
Treatment
Urinary Incontinence
Types and Causes of Incontinence
Diagnosis and Treatment
Special Needs of Elderly Persons
Urinary Tract Infections
Etiologic Factors
Host–Agent Interactions
Obstruction and Reflux
Catheter-Induced Infection
Clinical Features
Diagnosis and Treatment
Infections in Special Populations
Urinary Tract Infections in Non-Pregnant
Women
Urinary Tract Infections in Pregnant Women
Urinary Tract Infections in Children
Urinary Tract Infections in the Elderly
Interstitial Cystitis/Painful Bladder Syndrome
Cancer of the Bladder
Etiology and Pathogenesis
Manifestations
Diagnosis and Treatment
