essentials of pathophysiology chapter 27 disorders of the bladder and lower urinary tract
TRANSCRIPT
Essentials of Pathophysiology
CHAPTER 27
DISORDERS OF THE BLADDER
AND LOWER URINARY TRACT
CHAPTER 27
DISORDERS OF THE BLADDER
AND LOWER URINARY TRACT
PRE LECTURE QUIZ TRUE/FALSE
The storage and emptying of urine involves voluntary (somatic nervous system) control only.
Stress incontinence is the involuntary loss of urine during coughing, laughing, sneezing, or lifting, which increase intra-abdominal pressure.
The average bladder capacity (in ounces) is equal to the age (in years) + 2 of the child.
Urinary incontinence is not a common problem in elderly persons.
Flaccid bladder dysfunction is a neurogenic disorder of the bladder in which bladder emptying is impaired.
In flaccid (hypotonic) neurogenic bladder, volume is large, pressure is low, and contractions are absent. It may result from peripheral nerve damage or spinal cord damage at the S2 to S4 level (Overflow incontinence)
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PRE LECTURE QUIZ A neurogenic disorder of bladder function,
which is manifested as a failure to store urine, is known as __________ bladder dysfunction.
The most common sign of bladder cancer is painless __________.
__________ incontinence is characterized by the involuntary loss of urine that results from overfilling of the bladder.
The _______________ nervous system promotes bladder emptying.
In men, the most important cause of urinary obstruction is external compression of the urethra caused by enlargement of the __________ gland.
hematuria
Overflow
parasympathetic
prostate
spastic
MICTURITION REFLEX
Begins when bladder contains 150-250 mL of urine
ureters
urine produced in
kidneys
bladder fills with urine
STRETCH RECEPTORS IN THE BLADDER
stretch receptors
stretch receptors
bladder fills with urine
micturition center in pons
stimulated
spinal reflex stimulated
URINATION
Detrusor muscle of bladder contracts to push urine out
Abdominal muscles may also be used
Internal sphincter relaxes
External sphincter relaxes Unconscious in young
children Under conscious control in
adults
QUESTION
Tell whether the following statement is true or false:
Abdominal muscles are used during forced urination.
Controlling Nerves
Sympathetic- inhibits
detrusor and contracts sphincter
Parasympathetic- contracts
detrusor and inhibits
sphincter
ANSWER
True
Passive urination occurs when the bladder’s detrusor muscle contracts, and both internal and external sphincter muscles are relaxed. Abdominal muscles contract in order to force the excretion of urine.
PARASYMPATHETIC NERVES
M3 receptors
stretch receptors
M3 receptors
bladder fills with urine
detrusor muscle
contracts
internal sphincter relaxes and is pulled
open
parasympathetic neurons
spinal reflex stimulated
MICTURITION CENTER ALLOWS CONSCIOUS CONTROL
stretch receptors
bladder fills with urine
detrusor muscle
contracts
internal sphincter relaxes and is pulled
open
micturition center in
pons stimulated
external sphincter
relaxes
Conscious Control
QUESTION
All but which of the following stimulates urination?
a. Parasympathetic nervous system neurons
b. Micturition centerc. Sympathetic nervous systemd. Spinal reflex
ANSWER
c. Sympathetic nervous systemThe micturition center in the pons and the
spinal reflex respond to stretch receptors in the bladder to stimulate urination. The parasympathetic nervous system neurons are stimulated by the spinal reflex to cause urination. Sympathetic NS (fight-or-flight) decreases activity in both the excretory and digestive systems.
SCENARIO
A 63-year-old woman complains of stress incontinence, and her 60-year-old husband complains of difficulty voiding.
Question: Why do people of the same age and
lifestyle have opposite problems with urination?
MALE VS FEMALE URETHRA
Female is urethra 2.5–3.5 cm long
Allows urine to pass more freely
Male urethra 16.5–18.5 cm long Passes through prostate
QUESTION
Tell whether the following statement is true or false.
Benign prostatic hyperplasia (BPH) has no effect on the elimination of urine.
ANSWER
FalseBecause the male urethra passes
through the prostate gland, if the gland increases in size, the urethra may become compressed or obstructed. This decreases the diameter of the urethra’s lumen, and the ability to urinate is diminished.
SCENARIO
Six months later, the husband develops urgency and incontinence.
The doctor explains that it's due to his muscle strength.
Question Which muscles is the doctor talking
about? How did they cause incontinence?
BLADDER WALL HYPERTROPHY
The bladder may also pouch outward in diverticuli