physiology of micturition Flashcards
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
