w2 mictrution

Question 1

what nerves are associated with

somatic MN

parasympathetics

sympathetics

sensory

Answer 1

pudental

pelvic

hypogastric

pelvic

Question 2

what impact does the sympathic system have on the internal sphinctor

Answer 2

nternal sphincter contraction = promotes bladder filling

Question 3

what causes detrusor muscle contraction

Answer 3

parasympathetics

axons in pelvic nerve release ACh = detrusor contraction, urethral relaxation = promotes voiding

Question 4

what causes urethral contraction

Answer 4

somatic motor neuron

axons in pudendal nerve release ACh = external urethral sphincter contraction = VOLUNTARY prevention of voiding

Question 5

what reflex causes voiding/filling

Answer 5

voiding- Spino-bulbo-spinal reflex

filling- Lumbosacral spinal reflex

Question 6

outline the process of voiding

Answer 6

o Sensoryinputtoperiaqueductalgrey(PAG) when bladder is getting full

o StrongPAGactivation=pontinemicturition center (PMC) activated towards voiding
o PMCaxonsalterlumbosacralreflexactivity:

▪ Inhibits sympathetic and somatic motor output

▪ Activates parasympathetic output
o PMCmustcoordinatebladdercontractionandsphincterrelaxationtofullyvoidbladder
o Higherconsciouscontrol:prefrontal/insular/cingulatecortexalsoreceivessensoryinput,and

can inhibit PAG = prevents switch to voiding phase

Question 7

outine the process of filling

Answer 7

Sensory fibers report the bladder’s emptines so Sympathetic output predominates,whichalso

inhibits pre-ganglionic parasympathetic so Somatic motor output promotes guarding

reflex = external sphincter contraction

Question 8

what causes urge incontinence

Answer 8

detrusor hyperactivity

CNS prob

Question 9

what causes stress incontinence

Answer 9

spincter incontinence

Question 10

what causes overflow incontinence/ incomplete emptyng

Answer 10

outlet obstruction

detrusor hypoactivity

neurogenic bladder (disc or diabetes, alcoholism)

CNS prob

Question 12

what causes function incontinence

Answer 12

cognitive impairment

Question 13

how would cauda equina cause lower MN bladder disorder

Answer 13

•Bladder fills to max capacity, then dribbles,

•Urinary retention

•Overflow incontinence.

Detrusor large and flaccid –>

• Parasympathetic unable to contract bladder
• Loss of somatic efferentsmeans no voluntarycontrol of external sphincter
• Internal sphincter might still be innervated by sympatheticsfrom thoracic spinal cord, but internal sphincter tone cannot withstand additional pressure

Question 14

what could cause spastic bladder

Answer 14

•Loss of control from brainstem means loss of detrusor-sphincter coordination

upper MN disorder seen in MS or in traumatic spinal cord disorder

Question 16

will there be a retension problem if the detrusor-sphincter loop is still intact?

Answer 16

no

Question 17

what can cause urge incontinence and urinary urgency

Answer 17

• Loss of cortical input to brainstem (i.e. to PAG of midbrain)
• Without voluntary control from cortical oversight, pontine micturition center acts autonomously, triggering micturition whenever it senses sufficient fullness.