The document discusses the innervation of the urinary bladder. It describes how the bladder develops from three sources and its anatomy. The bladder has a detrusor muscle layer and two sphincters. Micturition is controlled by higher cortical and brainstem centers that coordinate sympathetic, parasympathetic, and somatic nerve pathways. The sympathetic pathway relaxes the detrusor and contracts the internal sphincter during bladder filling. The parasympathetic pathway contracts the detrusor and relaxes the internal sphincter during voiding. The somatic pathway controls the external urethral sphincter voluntarily. Neurogenic bladder can occur due to nerve damage and is classified based on the lesion level.

1. INNERVATION OF URINARY
BLADDER
Dr.Ponnilavan

2. DEVELOPMENT OF URINARY BLADDER
Developed from 3 sources:
• VESICOURETHRAL CANAL ( ENDODERM)
- Major parts of urinary bladder & prostatic urethra
• PROXIMAL PART OF ALLANTOIS ( ENDODERM)
- Apex of urinary bladder
• PROXIMAL PORTION OF MESONEPHRIC DUCTS ( MESODERM)
- Trigone of urinary bladder

3. ANATOMY OF BLADDER
• Anterior most element of the pelvic viscera.
• Situated in the pelvic cavity when empty, but expands superiorly into the
abdominal cavity when full.
• At BIRTH – EXTRAPERITONEAL AREA of LOWER ABDOMINAL WALL
• 5-6years – DESCENDS INTO TRUE PELVIS

4. ANATOMY OF BLADDER
TRIGONE- Smooth triangular area between
the openings of the ureters and urethra on
the inside of the bladder
The ureter pierces the bladder wall obliquely,
travels 1.5 to 2 cm, and terminates at the
urethral orifice. As it passes through the
hiatus in the detrusor (intramural ureter), it
is compressed and narrows considerably.
 The intravesical portion of the ureter lies
beneath the urothelium and backed by a
strong plate of detrusor muscle.

5. PARTS OF URINARY BLADDER

6. Anatomy of bladder
• DETRUSOR MUSCLE
Is a layer of the urinary bladder wall made of smooth muscle
fibres arranged in spiral, longitudinal and circular bundles.
• SPHINCTERS
Internal (smooth muscles ) sphincter – bladder neck and proximal
urethra
External ( striated muscle ) – membranous urethra

7. HIGHER CENTRE CONTROL
CORTICAL CONTROL AREAS
 Frontal and cingulate gyri – subcortical nuclei.
 Inhibition - micturition at the level of pons
 Excitatory - external urinary sphincter
 Voluntary control of micturition
PONTINE MICTURITON CENTRE
Barrington’s nucleus or M – region
Coordination of micturition.
SPINAL MICTURITON CENTRE
T11 – L2
Sympathethic and parasympathethic innervation.

8. MICTURATION – BLADDER INNERVATION
PARASYMPATHETIC SUPPLY: S2 S3 S4
- Contraction of detrusor muscle
- Relaxation of internal sphincter
FACILITATES MICTURATION
SYMPATHETHIC SUPPLY : L1 L2 L3
-Contraction of external sphincter
- Voluntary control
WITHOLDS MICTURATION

9. NERVE SUPPLY
Parasympathetic efferent fibers S2, S3, S4 are
- motor to detrusor muscle and inhibitory to the sphincter vesicae.
Sympathetic efferent fibers ( T11 to L2 )
- Inhibitory to detrusor and motor to sphincter vesicae.
The pudendal nerve ( S2, S3, S4 )
- Supplies sphincter urethrae which is voluntary
Sensory nerves
Pain sensations by both sympathetic and parasympathetic nerves

11. MICTURATION
REFLUX

12. TYPE OF NERVE NERVE FIBRES ACTION COMMENTS
SYMPATHETIC HYPOGASTRIC NERVE
(L1,L2L3)
INFERIOR MESENTRIC
GANGLION
MOTOR TO INTERNAL
URETHRAL SPHICTER,
INHIBITORY TO DETRUSOR
NO SIGNIFICANT ROLE IN MICTURITION; ALONG WITH IUS
PREVENT REFLUX OF SEMEN INTO THE BLADDER DURING
EJACULATION
PARASYMPATHETIC PELVIC NERVES (S2,S3,S4) MOTOR TO DETRUSOR
INHIBITORY TO INTERNAL
URETHRAL SPHINCTER
STRECH RECEPTORS PRESENT ON THE WALL OF THE
URINARY BLADDER SENSORY FIBRES IN THE PELVIC
NERVES INTERMEDIOLATERAL COLUMN OF SPINAL
CORD PARASYMPATHETIC NERVES MUSCARINIC
RECEPTORS EMPTYING OF URINARY BLADDER
SOMATIC PUDENDAL NERVES (S1, S3,
S4)
VOLUNTARY CONTROL OF
EXTERNAL URETHRAL
SPHICTER
THIS MAINTAINS THE TONIC CONTRACTIONS OF THE
SKELETAL MUSCLE FIBRES OF THE EXTERNAL SPHICTER, SO
THAT THIS SPHICTER IS CONTRACTED ALWAYS. DURING
MICTURITION, THIS NERVE IS INHIBITED, CAUSING
RELAXATION OF THE EXTERNAL SPHINCTER AND VOIDING
OF URINE
SENSORY HYPOGASTRIC, PELVIC AND
PUDENDAL NERVES
CORTICAL SENSATION

13. NERVE
ON DETRUSOR
MUSCLE
ON INTERNAL
SPHINCTER
ON EXTERNAL
SPHINCTER
FUNCTION
Sympathetic nerve Relaxation Constriction Not supplied Filling of urinary bladder
Parasympathetic
nerve
Constriction Relaxation Not supplied Emptying of urinary
bladder
Somatic nerve Not supplied Not supplied Constriction Voluntary control of
micturition

14. Bladder filling stage
Supraspinal centre inhibits PMC.
Increased thoracolumbar sympathetic outflow
Decreased sacral parasympathetic outflow to
lower urinary tract.
Increased activity of the pudendal nerve.
Detrusor smooth muscle relaxation, bladder
neck smooth muscle contraction, external
urinary sphincter contraction.

15. Bladder emptying stage
• Supra spinal centres’ inhibitory outflow to
PMC suppressed.
• Decreased thoracic sympathetic outflow.
• Increased sacral parasympathetic outflow.
• Supresed pudendal nerve
• Detrusor smooth muscle contraction,
bladder neck smooth muscle relaxation,
external urinary sphincter relaxation.

16. Neurogenic bladder

17. NEUROGENIC BLADDER
• Defined as the one whose function has been modified due to
interference with its nerve supply .

18. Epidemiology
• Usually affects
1. 40-90% multiple sclerosis
2. 37 – 72% Parkinsonism
3. 15% stroke
4. 70 – 84 % spinal cord injury
5. 61 % spina bifida
6. Other causes- autonomic neuropathy, pelvic surgery sequelae,
cauda equina syndrome

19. aims
• Preservation of renal function.
• Regular adequate emptying
• Prevention and control of infection and incontinence
• Minimize residual urine
• Judious and proper management –prevents renal damage .

20. NEUROGENIC BLADDER
classification & level of lesion
• Uninhibited bladder- lesions above the PMC
• Upper motor neuron bladder – lesions between PMC & Sacral spinal cord
• Mixed type A bladder – sacral cord lesions that damage detrrusor nucles but
spares pudendal nucleus
• Mixed type B bladder – sacral lesions sparing detrusor nucleus but damage
pudendal nucleus
• Lower MotorNeuron bladder – sacral nerve root injuries

21. • Uninhibited bladder :urinary frequency , urgency, incontinence.
• UMN bladder dysfunction: high bladder contractions – VUR – renal damage
• Mixed Type A bladder: hypertonic external urinary sphincter , urinary
retention
• Mixed type B bladder: flaccid external urinary sphincter , urinary
incontinence
• LMN Lesions – detrusor areflexia

22. Autonomous bladder
• Lesion : sacral segment of the spinal nerve
• Seen in:
1. Congenital : spina bifida, meningomyelocoele
2. Trauma
3. Infective : arachnoiditis, radiculitis
4. Neoplasms of the cord
• Affected individual may not be able to sense when the bladder is full
• Symptoms : difficulty in passing urine, urinary incontinence
• Bladder gradually over distends till the urine dribbles out

23. THANK
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