Bladder Neurophysiology

DR. ALI M AHMADMBBCH, MS, MD, MRCS-ED, EBPS

ASSOCIATE CONSULTANT PEDIATRIC SURGERY; KAAUH_ PNU

Anatomy of Urinary Bladder

Detrusor Fundus Neck

• internal sphincter Functional ,due to circular arrangement

• External sphincter Striated muscle under voluntary control

Trigone Located at base of bladder Extends from urethral orifices to bladder neck

Anatomy of Urinary Bladder

Storing the urine till convenient time to empty Function depends upon interaction among:

o Peripheral parasympathetico Sympathetico Somatic innervations

Modulation from central nervous system

Neuroanatomy of the micturition

Storing the urine till convenient time to empty

Function depends upon interaction among:

o Peripheral parasympathetico Sympathetico Somatic innervations

Modulation from central nervous system

Neuroanatomy of the micturition

Originates from T10 – L2

Travel to lumbar sympathetic ganglion and from there to fundus and neck through hypogastric nerves

Provide excitatory input to bladder neck and inhibitory to fundus of bladder {relaxation of detrusor and contraction of internal sphincter hence enhancing storage of urine}

Action through alpha & beta adrenergic receptors

Sympathetic Efferent

Originates from detrusor nucleus in S2-4 Travel through pelvic nerves to ganglion in

fundus of detrusor

Provide excitatory input to fundus of bladder & contraction of detrusor

Action through Action through cholinergic receptors

Para Sympathetic Efferent

Originates from pudendal nucleus in S 2-4

Travel through pudendal nerve

Provide excitatory /inhibitory output to pelvic floor & external sphincter

Somatic Efferent

Sensation carried through hypogastric, pelvic & pudendal nerves to dorsal columns of Lumbosacral spinal cord

In the spinal cord sensation carried through lateral spinothalamic and dorsal columns

Afferents

PONTINE MICTURITION CENTER Receives input from cerebral cortex ,

cerebellum , basal ganglion & hypothalamus

Most of the input is inhibitory but few are facilitatory.

Cerebellum important in o Maintenance of tone in pelvic flooro Co-ordination between bladder

contraction and external sphincter relaxation

Central control

MICTURITION HAS TWO PHASES

Filling PhaseVoiding phase

Occurs when person not trying to void Sensations of fullness carried through the afferents

and then through dorsal and spinothalamic tracts to pontine micturition center which is under the inhibitory influence of higher centers

Little rise in bladder pressure Maintained by progressive increase in sympathetic stimulation causing relaxation of body of bladder and stimulation of sphinctersS2-4 in

cauda equina

pelvic & pudendal ns

PMCFilling Phase

At convenient time and place Withdrawal of inhibitory influence from PMC & + Excitatory

input from other centers

Increase in parasympathetic derive Decrease in sympathetic derive Contraction of bladder and relaxation of sphinctersS2-4 in

cauda equina

pelvic & pudendal ns

PMCVoiding Phase