AUTONOMIC NERVOUS SYSTEMANATOMY PHYSIOLOGY AND DYSFUNCTION
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RICHA GUPTA MPT II YR
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Introductiony Involuntary AND automatic nervous system y
Primarily concerned with regulation of visceral or
vegetative functions
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Autonomic Nervous System
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DIVISIONS OF ANS
Sympathetic
ANS
Parasympathetic
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THIRD DIVISION OF ANS
ENTERIC NERVOUS SYSTEM
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SYMPATHETIC DIVISIONy Thoracolumbar outflow y Preganglionic
neurons: LGH of 12 thoracic & 2 lumbar
segments of SCy Preganglionic fibers
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Sympathetic ganglia
Paravertebral
Prevertebral
Terminal or Peripheral
Heart, Bronchi, pancreas, bladder
cervical Thoracic
Lumbar & sacral Sup. mesenteric Inf. mesenteric
Celiac
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PARASYMPATHETIC DIVISIONy CRANIOSACRAL OUTFLOW
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PARASYMPATHETIC DIVISION
Tectal or midbrain level
Bulbar level or bulbar outflow
Sacral outflow
Edinger Westphal Nucleus of CN III
VII, IX & X CN fibers
2, 3 & 4th sacral segment
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Functions of ANSy Regulation of functions which are beyond
voluntary control y Maintain homeostasis y SNS & PNS
antagonistic effect
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y Governs activities of cardiac & smooth muscles
including
smooth muscles of blood vessels & glandular functiony
Regulates respiration, circulation, digestion, temp
adjustment & metabolism
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Sympathetic Divisiony Stress responsesy Increased pulse &
respiratory rate y Vasoconstriction to skin & viscera y
Sweating (cold sweat) y Release of "adrenalin (epinephrine) y
Inhibition of digestive activity y Loss of appetite
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Parasympathetic Divisiony Relaxation responsesy y y y
Slower pulse & respiratory rate Increased blood flow to skin
& viscera Increased digestive activity SLUDy Salivation,
Lacrimation, Urination, Digestion/Defecation
y Increased reproductive interest, receptiveness y Penile
erection, engorgement of vulva
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No. 1. 2. 3. 4.
Effector organ Eye Ciliary muscle Pupil Lacrimal glands Salivary
secretion GIT- Motility Secretion Sphincters Gall bladder Urinary
bladder- Detrusor Internal sphincter Sweat glands Heart- rate &
Force of contraction Blood vessels- skin coronary ANS.ppt skeletal
msl
Sympathetic Relaxation Dilatation Decrease in secretion Decrease
Inhibition Decrease Constriction Relaxation Relaxation Constriction
Increase secretion Increase Increase Constriction Dilalatation
Constriction
Parasympathetic Contraction Constriction Increase Increase
Acceleration Increase Relaxation Contraction Contraction Relaxation
Decrease Decrease No effect No effect No effect No
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5. 6. 7. 8. 9.17
NO. 10.
EFFECTOR ORGAN LUNGS: Bronchiole Gland secretion
SYMPETHETIC
PARASYMPETHETIC
Dilatation Decrease
Constriction Increase
11.
Reproductive system: Male sex organs External genitalia Mucous
membrane
Ejaculation No action on BVs Capillaries constricted, Decreased
mucous secretion
No action dialatation No action
12.
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DETAILED ANATOMY
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Autonomic Nervous System:Anatomyy Two kinds of efferent neurons
y Preganglionic neuron/axony Cell body in CNS, axon to autonomic
ganglion (usu. myelinated)
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y Ganglionic neuron y Cell body in ganglion, postganglionic axon
to effector y (unmyelinated)
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Parasympathetic: Anatomyy Ganglia y Terminal, = intramural
gangliay in walls of viscera, close to effector cells
y Preganglionic axons relatively long
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PARASYMPATHETIC NERVOUS SYSTEMy
PREGANGLIONIC NEURONS:
Located partly in the brain stem in connection with:
3rd(occulomotor) 7th(facial) 9th(glossophyrangeal) and 10th(vagus)
. And partly in the 2nd,3rd & 4th sacral segment of spinal
cord. Hence called craniosacral outflow.
Parasympathetic:Anatomyy Parasympathetic pathway y Hypothalamus
& brain stem y Cranial or sacral outflow y Long preganglionic
axon to intramural ganglion y Short ganglionic neuron
(postganglionic axon)
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y POST GANGLIONIC NEURONS: Occulomotor nerve are situated in the
ciliary
ganglion. Facial nerve in pterygopalantine and submandibular
ganlion. Glossopharyngeal nerve in the otic ganglia. Vagus and
sacral component are loacated in the walls of target organs.
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Sympathetic:Anatomy y Sympathetic Ganglia1.Sympathetic trunk =
sympathetic chain ganglia paired on either side of vertebrae
2.Prevertebral = collateral ganglia unpaired among abdominal
viscera y Celiac ganglion y Superior mesenteric ganglion y Inf.
mesenteric ganglion y Aortico-renal y Superior hypogastric
3.Terminal or peripheral ganglia Suprarenal medulla as chromaffin
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Sympathetic Trunk Ganglia
Figure 15.8
y The trunk presents: 3 ganglia in cervical part ie
superior,
middle and
inferior 11 ganglia in thoracic part 4 ganglia in lumbar part 4
ganglia in sacral part
y some time inferior cervical and first thoracic ganglia are
fused to form a cervicothoracic or stellate ganglia. y Upper 4
cervical ganglia are fused to form the sup. Cervical ganglion, 5th
and 6th unite to form middle cervical ganglion y 7th and 8th
cervical ganglion join to form inf. Cervical ganglion.
y Each of thoracic and upper two lumbar sympathetic
ganglion is connected to the corresponding spinal nerves by both
white and gray rami communicants, white rami lying lateral to the
gray rami. White rami: convey preganglionic fibers from lateral
horn cells of T1-L2 segment of spinal cord through all thoracic and
upper two lumbar spinal nerves.Grey rami: convey post ganglionic
fibers from the lateral ganglia through all 31 pairs of spinal
nerves and their limb plexuses to supply sudomotor, pilomotor and
vasoconstrictor fibers to segmental skin viscera of body wall,
upper and lower limb and and vasodilator fibers to the skeletal
muscle.35 ANS.ppt 8/6/2011
Subsidiary ganglia: consist of collateral and terminal ganglia.
Collateral ganglia: are represented by coeliac,superior mesenteric,
inferior mesenteric, aortico renal ganglia and neurons in the sup.
Hypogastric plexus. Terminal ganglia: are formed only in the
suprarenal medulla as the chromaffin cells which liberate more
adrenalin than non adrenaline.
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Sympathetic:Anatomyy Adrenal medulla y One in each adrenal gland
y Develops as misplaced sympathetic ganglion y Neuron-like cells
without axons y Secrete epinephrine, norepinephrine
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s.no.
characterestic
SNS
PNS
1.
Origin
T1 to L2-L3 Thoracolumbar outflow Situated away from the organ
it supply Short
Cr ns. III,VII, IX, X Sacral. S2, S3, S4 Craniosacral outflow
Situated near or at the organ it supply Long
2.
Ganglia
3.
Preganglionic fibres
4.
Postganglionic fibers
Long
Short
5.
Neurotransmitters
Presynaptic- Ach Postsynaptic- nor adrenaline
Both Ach
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AUTONOMIC DYSFUNCTION
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y Acute autonomic paralysis ( dysautonomic polyneuropathy;
pure pandysautonomia)y Primary autonomic failure ( idiopathic
orthostatic
hypotension )y Peripheral neuropathy with secondary
orthostatic
hypotension
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y Autonomic neuropathy in infants & children (Riley-Day
Syndrome)y Autonomic failure in elderly y Horner
(oculosympathetic) & stellate ganglion syndromes
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y Sympathetic & Para sympathetic paralysis in Tetraplegia
&
Paraplegiay Acute autonomic crisis ( Sympathetic Storm ) y
Disorders of sweating y Disturbances of bladder & bowel
function
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ANS dysfunction following SCI
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Journal of Rehabilitation Research & Development. 2007
y Assessment of autonomic dysfunction following spinal cord
injury: Rationale for additions to International Standards for
Neurological Assessmentjoint committee of the American Spinal
Injury Association (ASIA) and the International Spinal Cord
Society
The committee recommends The recognition and assessment of the
following conditions: neurogenic shock, cardiac dysrhythmias,
orthostatic hypotension, autonomic dysreflexia, temperature
dysregulation, and hyperhidrosis.
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Neurogenic shocky Severe hypotension and bradycardia y An effect
of the imbalance in autonomic control, with an
intact parasympathetic influence via the vagal nerve and a loss
of sympathetic tone because of disruption in supraspinal
control
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y Can last upto 5 weeks post injury y Spinal shock
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Cardiac Dysrhythmiasy Depends on level & completeness of SCI
y Above T6:
reduction in sympathetic cardiovascular control hypotension
& bradycardia. Usually temporary
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Orthostatic Hypotensiony A decrease in systolic blood pressure
of 20 mmHg or a
decrease in diastolic blood pressure of 10 mmHg when the subject
moves from an supine to upright posture, regardless of whether
symptoms occur.Consensus Committee of the American Autonomic
Society and the American Academy of Neurology
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y Loss of supraspinal control of the sympathetic nervous
system below the lesion level frequently results in orthostatic
hypotensiony 2 grades of severity: Asymptomatic
Symptomatic
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y Symptoms : dizziness, nausea, light-headedness, or faintness y
Physical signs : pallor, diaphoresis, or loss of consciousness y
Common problem after acute cervical and high thoracic SCI
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MechanismInterruption of efferent pathways from the brain stem
vasomotor center to the sympathetic nerves involved in
vasoconstriction
Failure of short-term blood pressure regulation
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Pooling of blood in the viscera and dependent vasculature
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Autonomic Dysreflexiay Sudden bouts of hypertension (triggered
by afferent stimuli
below the lesion level)y Accompanied by piloerection, chills or
shivering, pounding
headache, paresthesias & flushing above the lesion level, as
well as nasal congestion, anxiety, malaise, and nausea
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y In both acute & later stages y Occurs as a result of
noxious or nonnoxious peripheral or
visceral stimulation below the lesion levely Primarily affects
subjects with lesions above the outflow to
the splanchnic and renal vascular beds (T5T6)
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y Found in subjects with both complete and incomplete
lesions
(C>I)y Irritation of the urinary bladder and GIT are among
the most
common causes
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Temperature Dysregulationy Occurs in the acute phase of SCI and
can potentially last a
lifetimey 3 categories Poikilothermia, or environmental fever,
from prolonged
cold exposure Quad fever without an infectious source
Exercise-induced fever
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Sweating Disturbancesy Hyperhidrosis y Most common pattern:
profuse sweating above the lesion
level with minimal or no sweating (hypohidrosis, anhidrosis)
below the lesion level
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International Standards for Neurological Classification of
Spinal Cord Injury: Training Effect on Accurate Classification
J Spinal Cord Med. 2008;31:538542
The International Standards for Neurological Classification of
Spinal Cord Injury: Intra-Rater Agreement of Total Motor and
Sensory Scores in the Pediatric Population J Spinal Cord Med. Apr
2009;32(2):157161
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Autonomic Peripheral NeuropathyRoy Freeman Neurol Clin 25 (2007)
277301
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y Small or Unmyelinated fibers are selectively involved.
S/S y Cardiovascular y Thermoregulatory y Gastrointestinal y
Urogenital y Pseudomotor y Pupillomotor
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Diabetic autonomic neuropathyy Manifests initially as an
increased resting heart rate caused by
a cardiac vagal neuropathy y Later on, sympathetic involvementy
Orthostatic hypotension occurs in diabetes as a consequence
of efferent sympathetic vasomotor denervation, causing reduced
vasoconstriction of the splanchnic and other peripheral vascular
beds
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y Bladder dysfunction: threshold for micturition reflex is
increased y GI Dysfn: diabetic gastroperesis y Constipation y
Diabetic diarrhoea y Loss of thermoregulatory sweating in a glove
and stocking
distribution: SNS dysfn y Hyperhydrosis
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Guillain-Barre syndrome
y Orthostatic hypotension
y Thermoregulatory problems
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Cardiovascular manifestation of autonomic involvement Sinus
tachycardia Bradycardia Asystole Tachyarrhythmias( fibrillation,
flutter) ECG changes (elevated or depressed ST segment changes, QT
interval prolongation) y Postural hypotension y Hypertensiony y y y
y y
Riley-Day-Syndrome (familial dysautonomia)y This syndrome has an
autosomal recessive mode of
inheritance and occurs primarily in Ashkenazic jewsy
Pathological studies show reduction in number of
preganglionic neurons in intermediolateral columns and also
small myelinated fibers in the ventral roots.
y Clinical features: y Diminished lacrimation y Hyperhydrosis y
Transient blotching of skin y Postural hypotension y Poor
temperature control
Autonomic Dysfunction in PD
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y Occur in 90% patients during disease course y May be the
result of other conditions (such as multiple
system atrophy [MSA]), the aging process itself, or
pharmacotherapy for PD
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Multiple System Atrophyy It is a degenerative disease with onset
in middle of life. Clinically characterised by any combination of
Parkinsonian, autonomic, pyramidal or cerebellar symptoms
and signs.
y Autonomic featuresy Postural faintness y Recurrent syncope y
Urinary incontinence y Faecal incontinence y Impotence in males
Localised Dysautonomic DisorderHorners syndrome Lesion affecting
pre ganglionic fibres from T1 and T2 at the inferior cervical
gangion is manifested by horners syndrome. Clinical features: y
Ptosis y Miosis y Anhidrosis y Enophthalmos1.
y Pre ganglionic lesion : Thoracic surgical trauma Trauma to
brachial plexus Aneurysm of aorta or subclavian artery
Post ganglionic lesion : Ischemia or compression of paracarotid
sympathetic pathways as a result of vasospasm
Holmes Adie Syndromey Pupil has decreased or absent light reflex
y A slow or delayed contraction to near vision y And slow or
delayed dilatation to dark
Causes y Degeneration of the ciliary ganglion and the post
ganglionic parasympathetic fibers of constrictor pupillae
muscle
Hirschsprungs diseasey Congenital y Absence of myentric plexus y
Segment of colon remain in constriction
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Raynauds Diseasey Raynauds disease characterized by constriction
of blood vesselsy Provoked by exposure to cold or by emotional
stress
Hypertensiony Hypertension high blood pressurey Can result from
overactive sympathetic vasoconstriction
AUTONOMIC DYSFUNCTION AFTER TBI???
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Dysautonomia after severe traumatic brain injuryEuropean Journal
of Neurology 2010, 17: 1172-1177 INCIDENCE: 11.8% Dysautonomia
after traumatic brain injury (TBI) is characterized by episodes of
increased heart rate, respiratory rate, temperature, blood
pressure, muscle tone, decorticate or decerebrate posturing, and
profuse sweating.
PATHOGENESIS: Epileptogenic etiology Disconnection theory
Excitation- inhibition ratio model
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THANK YOU
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