The document discusses the physiology of micturition and neuroanatomy of the bladder. It covers the anatomy of the bladder, urethral sphincter, and urethra. It then discusses the innervation of the bladder, control of micturition, and the mechanisms involved in micturition and voiding. It also covers geriatric and pediatric voiding physiology as well as classifications of neurogenic bladder and voiding dysfunction in various neurological disorders.

1. Physiology of micturition and
Neuroanatomy of bladder
MODERATOR:
• Dr Sanjai Singh
Assisstant prof
DEPT OF PMR
KGMU
PRESENTED BY:
• Dr Joe Antony
JR1
DEPT OF PMR
KGMU

2. Contents
1) INTRODUCTION
2) ANATOMY OF BLADDER, URETHRAL SPHINCTER & URETHRA
3) INNERVATION OF BLADDER
4) CONTROL OF MICTURITION
5) MECHANISM OF MICTURITION
6) VOIDING PHYSIOLOGY
7) GERIATRIC VOIDING PHYSIOLOGY
8) PAEDIATRIC VOIDING PHYSIOLOGY
9) CLASSIFICATION OF NEUROGENIC BLADDER
10) VOIDING DYSFUNCTION IN NEUROGENIC DISORDERS

3. INTRODUCTION
Micturition is process of passing urine. This is
primarily reflex phenomena which is mostly
integrated in spinal cord which is further
influenced by activation of higher centres
Urine formation starts in kidney
Urine flows down to bladder through ureter
Urinary bladder stores urine up to critical
volume & empty it at appropriate time following
suitable rise in pressure & critical volume.

4. BLADDER GROSS ANATOMY:-
It is hollow muscular distensible organ
in pelvis just above & behind pubic
bone.
Empty bladder-tetrahedral in
shape Full bladder -ovoid
It has:-
1) Apex
2) Neck
3) 3 surfaces-
Superior &right and left inferolateral

5. BLADDER
Anatomically it is divided into:-
DETRUSOR- composed of
smooth m/s bundle that
crisscross & interlace each other.
At bladder neck muscle fibre assume circular
arrangement which allow them to act as
functional sphincter .
TRIGONE:- located at inferior base of bladder.
Extends from urethral orifice to bladder neck.
Normal bladder capacity 400-500ml

6. URETHRAL SPHINCTER
• INTERNAL SPHINCTER:-
– It is consider as functional
sphincter because there is a
progressive increase in tone
with bladder filling so,that
the urethral pressure is
greater than intravesical
pressure.
• EXTERNAL SPHINCTER :-
– Is under voluntary control.
– The striated m/s fibre has
proportion of slow twitch
fibre with capacity for steady
tonic compression of
urethra.

7. FUNCTION OF URETHRAL SPHINCTER
External sphincter closed most of the time.
Sensation of filling bladder felt at volume of about 150 ml.
Sensation to pass urine is felt at 150-250ml
.
At 400ml sensation to pass urine become uncomfortable.
At 700ml it become very painful leading to loss of control.

8. URETHRA
.
Urethra contains inner longitudinal &outer semicircular layer of smooth m/s.
Circular m/s layer exerts a sphinctric effect along entire length.
FEMALE URETHRA is 3-4 cm
MALE URETHRA is 18-20cm
It has-
• Prostatic part (3cm)
• Membranous part (1.5)
• Penile part (15cm)

9. INNERVATION OF BLADDER
PARASYMPATHETIC FIBERS originates
from DETRUSOR nucleus located in
intermediolatral gray
matter of sacral cord S2, S3 ,S4 to reach bladder
via pelvic nerve
Cholinergic receptors( M2>M3)
Contraction of bladder
(They are mainly distributed in the body of
bladder ,TRIGONE, bladder neck & urethra.)

10. SYMPATHETIC FIBERS originates in
intermediolateral gray column from T11 toL2
& reach bladder via hypogastric nerve.
Alpha receptor concentrated in
TRIGONE, bladder neck, urethra leading
to maintenance of continence by
contracting bladder neck.
beta receptor concentrated in body of
bladder leading to its relaxation which
enhance storage.

11. SENSORY /AFFERENT FIBERS:PELVIC NERVE
It has 2 types:-
Small myelinated A delta:- Respond in graded fashion to
bladder distension which is needed for normal voiding.
Unmyelinated C fibers:- They do not respond to bladder
distension. Only activated by chemical or cold temperature
irritating bladder wall.

12. INNERVATION OF URETHRAL SPHINCTER
INTERNAL SPHINCTER:-
innervated by sympathetic & parasympathetic nerve
therefore it is under autonomic control.
EXTERNAL SPHINCTER:- somatic fibers originated from
S2 ,S3, S4 innervate bladder & external sphincter via
pudendal nerve.

13. INNERVATION OF BLADDER &URETHRAL SPHINCTER

14. CONTROL OF MICTURITION
•Micturition reflex controlled by brain stem.
Facilitatory area and area of
coordination present in pons
•Inhibitory area present in
midbrain
•Posterior hypothalamus facilitatory areafor
micturition
•Cortex has voluntary inhibitory control on
micturition

15. MICTURITION REFLEX
Filling of bladder
Stimulates stretch receptor (A delta
fibers) present in wall of bladder
Center for spinal reflex is sacral S2,3
&4 segment of spinal cord
Stimulate motor fibre of
parasympathetic system causing
contraction of detrusor muscle
leading to MICTURATION

16. VOIDING PHYSIOLOGY
FILLING PHASE
There is little rise in bladder pressure
Intravesical pressure is maintained by sympathetic stimulation
beta receptor, alpha receptor- increase in urethral sphincter tone
Full intravesical pressure (0-6cm of H2O &it should not be>15 cm of H2O
Filling continued leading to steady progressive rise in intravesical pressure

17. EMPTYING PHASE
Cessation of urethral sphincter pressure & funneling of bladder neck
No reflex inhibition to sacral micturation centre from sphincter
Detrusor contraction
Urethral sphincter kept open throughout micturition & no rise in
intravesical pressure during voiding

18. GERIATRIC VOIDING PHYSIOLOGY
The Kidney undergoes age related changes in which there is :-
1) decrease in Glomerular blood flow & renal blood
flow 2). decrease in concentrating ability
There is increase urgency with increase daytime frequency
&nocturia ,incontinence & incomplete emptying in absence
of identified cause.
Urodynamic studies shows that older adults have involuntary
bladder contraction during filling which leads to these symptoms.

19. PEDIATRIC VOIDING PHYSIOLOGY
In newborn sacral micturition reflex is primarily responsible for voiding.
There is little inhibition of micturition reflex from the cerebral cortex.
Neonates & infants have involuntary reflex voiding occur at 50-100ml.
At 1yr childshows awareness of bladder evacuation & can begin to delay
urination for a brief period by contracting sphincter
voluntary.
5yrs 90% children voluntary control of micturition.

20. CLASSIFICATION
OF
NEUROGENIC
BLADDER

21. CLASSIFICATION OF NEUROGENIC BLADDER

22. VOIDING DYSFUNCTION IN
NEUROLOGICAL DISORDERS
• Supra pontine lesions
• Supra sacral/ Pontine lesions
• Sacral spinal cord lesions
• Infra sacral lesions

23. Supra pontine lesions
• Lesions- CVA,degenerative diseases, hydrocephalus,
IC neoplasms,TBI, Parkinsons disease, Multiple
sclerosis
• Inability to initiate voiding, inappropriate timing,
detrusor overactivity incontinence
• Normal detrussor- sphincter synergy

24. PARKINSON’S DISEASE
•Delayed relaxation of sphincter
•Delay in urine flow on attempted voiding
•If pontine micturition center is also affected, urinary retention
and overflow incontinence ( acontractile bladder)

25. Multiple sclerosis
•In this 90% pt. develop urinary manifestation.
•White matter of spinal cord also involved to
a varying degree
•Presents with variable features

26. SURASACRAL SPINAL CORD/PONTINE
LESION
Traumatic SCI - m/c suprasacral lesion affecting voiding.
Other cause are:- transverse myelitis,
primary or metastatic tumour etc.
Initial period of spinal shock - Areflexia of somatic
system below level of injury- detrusor areflexia – urinary
retention

27. • Initial reflex return ( such as bulbo cavernous reflex) in 1-3 days
• Recovery of bladder function follows recovery of skeletal muscle reflexes
• Spinal shock is not an all or nothing phenomenon
• Beginning of involuntary bladder contractions- can be considered as ‘Out
of spinal shock’- Usually 6-8 weeks
– BCR
– ICE WATER TEST

28. •Detrusor areflexia - Uninhibited bladder contraction
become stronger leading to postvoidal residual
volume decrease.
•PVR reaches lowest by 12 weeks of injury
•After that, expected finding will be, detrusor
overactivity with significant detrussor-sphincter-
dyssenergia, resulting in significant PVR ( high
pressure bladder)

29. SACRAL LESION
•LESION ARE:
1. spinal trauma,
2. herniated lumbar disc,
3. primary or metastatic tumour
4. lumbar stenosis,
5. intervertebral disc protrusion & prolapse
leading to cauda equina syndrome.

30. Damage to sacral cord or root
Acontractile bladder usually with
impaired sphincter activity (decreased
compliance may or may not be seen)
In partial injury
Areflexia with decrease bladder
compliance- progressive increase in
vesical pressure

31. PERIPHERAL LESION
M/c lesion is peripheral neuropathy secondary to DM.
Other cause are:- Chronic alcoholism,
• herpes zoster,
• GB syndrome,pelvic surgery.
there is decrease bladder sensation, bladder
overdistension and increased PVRs

32. • Thank you