1. Autonomic nervous system
Sympathetic nervous system
Dr
Swati Patil
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2. • Autonomic nervous system
-History
-Introduction
-Types :- Sympathetic –Development
-Introduction
-Course
-Types
-Applied
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3. Autonomic Nervous System
• Self regulating
• History:
– 1898 - J.N.Langley assigned the term Autonomic
Nervous System
– 1921 – subdivided ANS into
• Sympathetic
• Parasympathetic
• Enteric
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4. 4

5. Autonomic Nervous System
• Introduction
– Visceral component of
nervous system ,
function closely related
to somatic nervous
system
– Visceral afferent
pathways resemble
somatic afferent
– Peripheral processes –
auotonomic ganglia –
somatic nerves
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6. Visceral Afferents
-Cell bodies –unipolar –
present in cranial sensory or
dorsal root ganglia
-Central processes –with
somatic afferents into CNS
–establish connections
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7. Visceral Efferent
• Visceral efferent
pathways in ANS differ
from their somatic
equivalents
• pre-ganglionic neurons:
– Somata are located in
• visceral efferent nuclei &
• in lateral grey columns
– axons are
• myelinated ,
• pass to peripheral ganglia
• synapse with
postganglionic neurons
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8. Visceral Efferents
Pre-ganglionic Post-ganglionic
ganglion
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9. • Post-ganglionic neurons –axons are unmyelinated ,
more numerous
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10. Subdivisions of ANS
• Sympathetic
• Parasympathetic
• Enteric
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11. • Sympathetic –mass
response
- Constriction of cutaneous
arteries
- Cardiac acceleration
- Rise in blood pressure
- Contraction of sphincters
- Depression of peristalsis
• Sympathetic:
mobilization & increased
metabolism
“fight, flight or fright” or
“fight, flight or freeze”
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12. Neurotransmitters:
• pre-ganglionic neurons of
both are cholinergic
• post-ganglionic
– parasympathetic –cholinergic
– sympathetic –nor-adrenergic
• principal co-transmitters
– ATP , Neuropeptide Y
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13. Sympathetic Nervous System
• Development :-
-During 5th week, neural crest
cells migrate along sides of
spinal cord ganglia -
dorsolateral to aorta
-Some neural crest cells
migrate ventral to aorta
pre-aortic ganglia – celiac
& mesenteric ganglia
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14. • Other neural crest cells
migrate to heart, lungs, GIT
terminal ganglia
• Axons of sympathetic
neurones in
intermediolateral cell
column of thoracolumbar
seg of spinal cord
pass through ventral root of
spinal nerve & white ramus
communicans to reach
paravertebral ganglia
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15. • Synapse with neurons –
ascend / descend in
sympathetic trunk
• Other presynaptic fibers –
pass through paravertebral
ganglia without synapsing –
splanchnic nerves to viscera
• Post synaptic fibres –grey
rami from sympathetic
ganglion into spinal nerve
• Sympathetic trunk –
ascending & descending
fibres
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16. Sympathetic Trunk
• Two ganglionated nerve
cords –either side of
vertebral column
• White & grey rami
communicantes
• Location –neck ,thorax,
abdomen, pelvis
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17. Preganglionic neurones:
• Cell bodies of preganglionic
sympathetic neurons –in
lateral horn
• Axons –myelinated ,diam
-1.5 - 4 microm
• Leave cord in ventral nerve
roots – pass into spinal
nerves, soon leave in white
rami communicants
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18. Behaviour of Preganglionic Fibres
• Synapse with neurons in
nearest ganglion or may
ascend or descend
• Fibres terminate in single
ganglion or through
collateral branches –
synapse
• Fibres may ascend or
descend without synapsing
–emerge in branches of
sympathetic trunk –synapse
in ganglia of autonomic
plexus
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19. Postganglionic Neurones of Sympathetic
Nervous System
• Somata of postganglionic
neurons –in ganglia of
sympathetic trunk
• Axons –unmyelinated,
return to spinal nerve
through grey ramus just
proximal to white ramus &
then form dorsal & ventral
ramus
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20. Cervical Sympathetic Trunk
• B/w Carotid sheath and
prevertebral muscles
• Internal carotid nerve
• Three cervical ganglia
– Superior
– Middle
– Inferior
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21. Superior Cervical Ganglion
• Largest ganglion
• Lies in front of transverse
processes of C2 and C3
vertebrae
• Branches
– Medial
– Lateral
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22. Middle Cervical Ganglion
• Smallest of the Cervical
ganglion
• Lies on the C6
vertebra in front or behind
Inf. thyroid artery
• Branches
– grey rami communicantes
– Cardiac branch
– Vascular Branch
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23. Stellate Ganglion
• Formed by the fusion of
C7,C8 andT1 ganglia
• Lies b/w neck of 1st Rib and
transverse process of C7
vertebra
• Branches
– Grey rami communicans
– Vascular branches
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24. Sympathetic supply – Head and Neck
• Preganglionic fibres – T1-T5
segments of Spinal Cord
• Ascend in Sympathetic Trunk
• Synapse in cervical ganglia
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25. Thoracic Sympathetic Trunk
• Comprises of 11 ganglia
• Ganglia lie against the
heads of ribs
• Branches
– Grey rami
communicans
– Pul. And cardiac
Plexus
– Splanchnic Nerves
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26. Coeliac Plexus
• Situated around the origin
of coeliac artery
• Formed by greater
Splanchnic Nerves and Ist
lumbar sympathetic nerves
• Nerves from the plexus
supply abdominal viscera
via blood vessels
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27. Lumbar Sympathetic Trunk
• Lies retroperitoneally on
the anterolat. surface of
lumbar vertebrae
• Rt side – overlapped by IVC
• Lt side – overlapped by
Aorta
• Branches
– Splanchnic nerves
– Grey rami communicantes
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28. Hypogastric Plexuses
• Superior hypogastric plexus:-
-location
-formation
-branches
• Inferior hypogastric plexus :-
-location
-formation
-branches
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29. Adrenal Medulla
• Neural crest cells –
secretary cells of medulla
• Sympathetic supply –
preganglionic sympathetic
neurons
• Secretary cells –
postganglionic sympathetic
neurons –lack axons or
dendrites
• Larger secretory cells –
secrete adrenaline & NA
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30. Summary
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31. Sympathetic Ganglion
Histology :
• Connective tissue,
ganglion, capsule cells
• Nerve cells –multipolar,
smaller
• Nucleolus –prominent
eccentric
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32. Sympathetic Ganglion
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33. Enteric Nervous System
• Myenteric (Auerbach’s)
plexus & submucosal
(Meissner) plexus
• Plexus –small enteric
ganglia –joined by thin
nerves –unmyelinated
• Avascular –nutrition by
diffusion
• Neurones –excitatory &
inhibitory
• Afferents to ENS -2 types –
cholinergic & NA
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34. Pain Afferents
• Sensory neurones –pain
in thoracic & abdominal
organs
• Cell bodies –dorsal root
ganglia
• Peripheral processes –
white communicating
rami –sympathetic trunk
–viscera
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35. • Referred pain –diffuse
localization & radiation
• Zone of reference of pain
from int organ coincides
with part of body served
by somatic sensory
neurons assoc with same
segment of spinal cord
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36. Referred Pain
• Heart –middle &
inferior cervical cardiac
nerves, thoracic cardiac
branches of left
sympathetic chain
• Gall bladder –greater
splanchnic nerve ,
diaphragm –phrenic
nerve
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37. • Stomach –epigastrium –
Rt & Lt greater splanchnic
nerves
• Duodenal ulcer –AAW –
T9 T10
• Appendix –lesser
splanchnic nerves –T10
• Pelvis & ureter –least
splanchnic nerves –loin &
groin
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38. Surgical Sympathectomy
• Indications
– Peripheral vascular disease –sympathectomy –temporary
vasodilatation –development of collaterals
– Hyperhidrosis –sympathectomy –permanent relief
– Relief of Pain –a) visceral pain –excision / destruction –
coeliac ganglia –Ca pancreas, chronic pancreatits
– b) causlgia –intense pain
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39. Upper Thoracic and Cervical
Sympathectomy
• Upper limb -2 & 3 thoracic
ganglia with rami &
intervening part
• 1st thoracic –not removed,
preganglionic fibres not
arise above T2 (removal –
Horner’s syndrome)
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40. Kuntz Nerve
• Communicating branch B/w
T1and T2 nerves
• Receives Grey rami from
Stellate and T2 ganglia
• Clinical relevance –failure
to identify during thoracic
sympathectomy
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41. Lumbar Sympathectomy
• Gangliectomy -3 & 4
lumbar ganglia &
intervening trunk
• Removal of LI is harmful
– interferes with
ejaculation
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42. Horner’s Syndrome
• Preganglionic –white ramus
of T1 –sympathetic trunk –
superior cervical ganglion –
postganglionic fibres (ICA) –
ophthalmic –nasociliary –
long ciliary branches
• Damage –vascular lesions of
cortex / brainstem, cervical
rib, Ca lung, thyroid,
oesophagus
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43. Clinical features of
Horner’s syndrome:
• Miosis –failure dilation –
unopposed
parasympathetic activity
• Partial ptosis –paralysis of
LPS
• Anhydrosis –lesion of
superior cervical ganglion
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44. Central Control of Sympathetic
Nervous System
• Hypothalamus –controlling
&integrating center
• Hypothalamus –autonomic
nuclei –spinal cord –
reticular formation
• Posterior & lateral nuclei –
noradrenergic response
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45. THANK YOU… 45