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25 Cards in this Set
- Front
- Back
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what are the three anatomical divisions of the urinary tract
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the upper urinary tract, bladder, urethra
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s2,3, 4 are part of the micturition center and travel in the __ __ then cause the bladder to contract and sphincter to relax
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pelvic nerve
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the hypogastric nerve innervates
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the bladder and urethra
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ureters are supplied with __ and __ fibers
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parasymp and symp
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what role does parasymp stim have on the ureters
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increases frequency of peristaltic contractions in ureter, increasing urine delivery to bladder
and symp- slows peristalsis |
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what does the stress relaxation mech do for the bladder
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minimizes pressure rise as bladder fills- it does this by initiating contractions with parasymp
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__ __ from bladder wall, posterior urethra are activated by stretch
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sensory fibers
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__ __from sacral micturition center (pelvic nerve) stimulate detrusor muscle, inhibit contraction of internal urethral sphincter
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parasymp fibers
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(__ __ hypogastric nerve) inhibit detrusor, constrict internal urethral sphincter
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symp nerves
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__ __ __(voluntary; pudendal nerve) constrict external urethral sphincter
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somatic motor neurons
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what is the equation for tension in early bladder filling
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T=pxr/2
as pressure increases |
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bladder stretch receptors are activated and send stretch sensory info to:
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1.Sacral micturition center: activates parasympathetics
2. Higher centers in brainstem, cerebral cortex: suppress parasympathetic impulses |
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what are the 4 main things that happen in later bladder filling
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1. Increasing wall tension more frequent sensory impulses from stretch receptors
2. Inhibition of sacral micturition center by higher centers in brain is overridden 3. Parasympathetic impulses from sacral cord:stimulate bladder contraction nhibit contraction of internal urethral sphincter 4. Urine enters posterior urethra |
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what happens after urine enters urethra
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Sensory impulses from urethra to sacral cord inhibit somatic nerves that constrict external sphincter
Bladder continues to fill; its contractions intensify Sensory impulses from bladder and urethra become more powerful. When the time is right external sphincter relaxes, urine is voided |
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__ __ maintains intravesical pressure despite decreased tension
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decreased radius
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what is the cause of atonic bladder
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destruction of sensory inputs from bladder to sacral cord
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what happens to the atonic bladder
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Stretch information no longer transmitted; bladder contractions are no longer initiated.
Bladder becomes flaccid, filled to capacity; eventually distended, thin-walled. |
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what dz is assoc with atonic bladder
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spyhillis
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what causes denervated bladder
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destruction of both afferent and efferent fibers between bladder and cord
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what happens to the bladder in a denervated bladder
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Initially: detrusor contractions cease; bladder becomes flaccid, distended
Later: detrusor regains spontaneous activity; bladder shrinks, hypertrophies ( small thick walled) |
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what is the cause of automatic bladder
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injury or severing of spinal cord above sacral region: cuts off communication with brain
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what happens to the bladder in an automatic bladder
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Acute phase: ‘spinal shock’ temporarily suppresses micturition reflex
Micturition reflex can gradually recover, although control by brain is lost. |
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what is the cause of uninhibited neurogenic bladder
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destruction of tracts carrying inhibitory impulses (- · - · -) from brain
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what happens to the bladder in uninhibited neurogenic bladder
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Facilitatory inputs (- - -) remain intact; micturition ctr. is continually stimulated
Micturition is activated by small amounts of urine Detrusor hypertrophies, bladder capacity reduced |
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bladder pressure is maintained during voiding by law of
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la place
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