physiology of micturition Flashcards
(16 cards)
stimulation of which receptors would treat urinary incontinence + MOA
Beta -3 agonists
causes the detrusor to relax so increases bladder capacity
Nerve roots of pudendal nerves
S2-S4 contraction of external urethral
Which nerves involved in the voluntary somatic control of bladder + muscles during storage
Pudendal nerves - act on nictotinic receptors on striate muscles on EUS.
How does the sympathetic innervation of the ANS in storage works:
Impulses -> spinal cord T10-L2 -> via hypogastric nerve -> Destrusor relaxation + IUS contractions.
What happens to intravesical pressure as the bladder fills up
Remains constant and LOWER than that of the urethra.
Prevents leakage.
What can cause a reflex bladder
- MS
- Trauma
- strokes
- brain tumours
- parkinson’s disease.
Which receptors, when stimulated causes detrusor muscle contraction
M3 muscarinic receptors
At what bladder volume do afferent signal to void the bladder
400ml
Typical male urinary flow rate
20-25ml/s
which nerve is responsible for causing contraction of detrusor muscle during micturition
Pelvic nerve.
Parasymapthetic stimulation
Release of acetylcholine -> M3 receptors binding
which nerve roots give rise to pelvic nerve
S2-4
urinary flow rate in women
25-30ml/s
what happens to 3 muscles during voiding
Smooth muscle of IUS = relax
Striated muscles of EUS = relax
Detrustor muscle = Contracts
nerve involvement in voiding phase:
- Cortex - detects strong desire to void
- PMC - co- ordinates void
- Sympathetic - inhibited = activity turned off
- Somatic = conscious relax of phasbosphincter
- Parsympathetic - destrusor contraction.
what happens if destrusor doesnt contract enough
failure to contract during emptying
incomplete emptying
urinary retention
luts, utis, high pressure retention
what happens if sphinctor doesnt relax
failure to relax during empyting phase
destrusor contracts against closed sphinctor = wrong time
AKA destrusor-sphincter dyssynergia
