Renal micturition and incontinence Flashcards
Where do the sympathetic fibres involved in nerve supply of urine bladder originate from?
Sympathetic fibres originate in the T11–L2
What is the course of the sympathetic fibres like from the point of origination to pelvic nerves?
Run through the inferior mesenteric ganglia (plexus, IMP) and the hypogastric nerve (HGN) or through the paravertebral chain to enter the pelvic nerves at the base of the bladder and the urethra.
Where do parasympathetic preganglionic fibres fibres involved in the nerve supply of urine bladder arise from?
S2-S4
What is the course of the parasympathetic preganglionic fibres from the point where they arise to the ganglia in the pelvic plexus and in the bladder wall?
travel in sacral roots and pelvic nerves (PEL) to ganglia in the pelvic plexus (PP) and in the bladder wall.
Where do the somatic motor nerves that supply striated muscles of external urethral sphincter arise from and where do they pass through?
Somatic motor nerves (yellow) that supply the striated muscles of the external urethral sphincter arise from S2–S4 motor neurons and pass through the pudendal nerves.
What do parasympathetic postganglionic acons in the pelvic nerves release, what do they stimulate and what effect does this bring about?
Parasympathetic postganglionic axons in the pelvic nerve release acetylcholine (ACh), which produces a bladder contraction by stimulating M3 muscarinic receptors in the bladder
What do sympathetic postganglionic neurons release in the bladder and urethra, what do they stimulate and what effect do they bring about?
Sympathetic postganglionic neurons release noradrenaline (NA), which activates β3 adrenergic receptors to relax bladder smooth muscle and activates α1 adrenergic receptors
What do somatic axons in the pudendal nerve release, what do they activate and what does this result in?
Somatic axons in the pudendal nerve also release ACh, which produces a contraction of the external sphincter striated muscle by activating nicotinic cholinergic receptors.
What is the sympathetic nervous system responsible for in the bladder?
Sympathetic nervous system responsible for urinary retention
What is the parasympathetic nervous system responsible for in the bladder?
Parasympathetic nervous system responsible for voiding
What are the steps involved in the initiation of micturition?
Stimulation of Micturition centre in Pons
Preganglionic parasympathetic
(inferomedial grey column)
S2 S3 S4 segments
Inferior hypogastric plexus
Post-ganglionic neurons
Detrusor muscle
Acetyl choline
Muscarinic receptor (M3)
Contraction of bladder
What protects the bladder?
The urethra
How does urine flow -unidirectional prevent UTI?
Physical removal of bacteria from the urinary tract
How does mucus and mucin prevent UTI?
Traps and prevents bacterial adherence to the
epithelium
How does tam horsfall protein prevent UTI?
Competitive inhibition of bacterial binding to the protein
