BLADDER INNERVATION NOORMIN HAIDA ADENAND
BLADDER INNERVATION
NOORMIN HAIDA ADENAND
• Normal voiding is a spinal reflex• Modulated by - CNS (Brain, brain stem & spinal cord) - PNS (ANS & somatic nervous system)• Micturation control center is located in the frontal
lobe
• Signal transmitted by brain is routed through brainstem & spinal cord prior to reaching the bladder.
• Mechanical process of urination is coordinated by pons in Pons Micturation Center
- coordinates - urethral sphincter relaxation - detrusor muscle contraction - facilitates urination
• Bladder full stretch receptors of detrussor muscle
pons brain
pons
inhibit bladder fr contracting
• Spinal cord act as important intermediary between pons & sacral cord
• Sacral cord has specialized area known as sacral reflex center
- responsible for bladder contraction - is the primitive voiding center
• In infants, higher center of voiding control (the brain) is not mature enough to command the bladder
- when urine fills the infant bladder
excitatory signal
sacral cord
detrusor to contract
involuntary detrusor contraction with coordinated voiding
• ANS - regulates action of internal organs under involuntary control - divided into sympathetic parasympathetic • Sympathetic - bladder to increase its capacity without detrusor resting pressure - + internal urinary sphincter to remain tightly closed - urinary accomodation occurs - - micturation reflex
• Parasympathetic - + detrusor muscle to contract• Pudendal nerve - originates from nucleus of Onuf - regulates voluntary actions of
external sphincter diaphragm - its activation causes contraction of the above muscles
Synergistic Dysfunction• Abnormal neuronal supply to the bladder
increased contraction of the detrusor
• However, as there is coordinated relaxation of the internal & external urethral sphincters
voiding of urine
• These bladders are generally safe with low association intravesicular pressures
have a release valve through the sphincter
• Unlikely to cause renal damage
Dysynergistic Dysfunction
• Detrusor and urethral sphincter contraction is uncoordinated which results in
- high vesicular - detrusor hypertrophy - vesicoureteric reflux - renal damage• Unsafe bladders• Need to be treated early to minimize the damage
caused to the kidneys
Atonic Dysfunction
• Lack of detrusor and often sphincter activity• These systems are at low pressure &
generally safe• The bladder is commonly capacious• Constant dribbling incontinence• Do not cause upper tract damage
• The 3 above types are difficult to distinguish in the young as they can all result in children who wet.
• Can only be assessed by detailed urodynamic studies