Urinary tract and micturition Flashcards
What structures are apart of the upper urinary tract
calyces, pelvis, ureters
what are of urinary tract controls voiding
the urethra
What structures are apart of the upper urinary tract
calyces, pelvis, ureters
What structures are apart of the upper urinary tract
calyces, pelvis, ureters
Describe the sphincters of the urethra
internal is involuntary- wall of bladder as narrows to urethra
external is voluntary- skeletal that wraps around exterior of urethra where if joins bladder
Where does bladder pain travel
anterolateral column via hypogastric plexus S2-S4
where is bladder fullness sensed(nerves)
pelvic splanchnic nerves
describe the reflex arc for micturition
primary arc from bladder to bladder via sacral detrusor nucleus
secondary arc from urethra to voluntary sphincter
What do the parasympathetics do to bladder
stimulate detrusor, inhibit contraction of internal urethral sphincter
what do the sympathetics do to bladder
hypogastric nerve, it inhibits the detrusor constriction and constricts internal urethral sphincter
whare are the somatic nerves to bladder
pudendal that constrict external sphincter
Where is the micturition center located
pontine micturition center in the locus ceruleus of the pons
can the bladder overcome the micturition control center
yes, when it is so full
What is the PANS and SANS activity on ureters
PANS stimulates increased perstaltic motions white SANS inhibits this
What does a cystometrogram measure in bladder
The V/P in bladder
how does Volume and P change as the bladder fills
volume expands at a pretty constant pressure due to the elasticity of the bladder
What happens to the wall tension as the bladder fills
as radius increases, wall tension increases
when bladder stretch R are activate what happens
sensory information is sent to the sacral micturition center to activate PANS
higher centers in brainstem inhibit the PANS impulses
Describe when PANs inhibition is overridden
increased wall tension to a high frequency(around 400mL) and this inhibits the sacral micturition center and the PANS impulses are transmitted to stimulate contraction and inhibit contraction of internal sphincter
After the urine enters the urethra what happens
sensory impulses from urethra to sacral cord inhibit the constriction of external sphincter and when time is right–> void
how does the bladder completely empty while staying passive
the tension of the baldder wall declines as urine leaves–> maintains P with decrease in V
What are the 4 basic abnormalities with micturition
atonic bladder
denervated bladder
autonomic bladder
uninhibited neurogenic bladder
What is an atonic bladder
stretch info is not transmitted, bladder contractions no longer initiated
what causes atonic bladder
destruction of sensory inputs from bladder to sacral cord (DM, syphilis, MS))
what is the long term result of atonic bladder
overflow incontinence, distended and thin-walled
what causes a denervated bladder
destruction of both afferent and efferent fibers between bladder and cord
what is the intial result of a denervated bladder and long term result
initial: detrusor mm contractions stop and bladder is flaccid and distended
later: detrusor regains spontaneous activity; bladder shrinks and muscle wall hypertrophies
What causes an autonomic bladder
injury or severing of spinal cord above sacral region
What is the acute and chronic phase of an autonomic bladder
acute: spinal shock which temporarily suppresses micturition reflex
reflex can gradually recover and become exaggerated leading to spasticity and all control by brain is lost
What is the cause of an uninhibited neurogenic bladder
destruction of tracts carrying inhibitory impulses
what inputs are still in tact in an uninhibited neurogenic bladder
facilitatory (micturition control)
What is the net result of an uninhibited neurogenic bladder
micturition activated with small amounts of urine
detrusor hypertrophies and the bladder capacity is reduced
What happends during an UTI
uninhibited contraction of detrusor muscle with facilitation of micturition reflex
urinary frequency and leakage
what are of urinary tract controls voiding
the urethra
Describe the sphincters of the urethra
internal is involuntary- wall of bladder as narrows to urethra
external is voluntary- skeletal that wraps around exterior of urethra where if joins bladder
Where does bladder pain travel
anterolateral column via hypogastric plexus S2-S4
where is bladder fullness sensed(nerves)
pelvic splanchnic nerves
