A basic physiology lecture on the autonomic nervous system and its functions for undergraduates and postgraduates.

1. Autonomic Nervous
system
Dr. Mrs.Minakshi Ashok Randive
Professor & head - Kriyasharir
Tilak Ayurved Mahavidyalaya, Pune .

2. Introduction
• ANS is mostly concerned with regulation of
visceral functions in the body , it is also called
involuntary Nervous system .
• Divisions - 1 - Sympathetic division
2 - parasympathetic division

3. Sympathetic division
• The preganglionic neurons are situated in lateral
grey horns of twelveth thoracic and first two
lumbar segments of spinal cord .
• Arising fibers from here are called as
preganglionic fibres .
• Preganglionic fibres leave the spinal cord
through anterior nerve root and white rami
communicants - terminates -post gang.neurons.

4. Sympathetic Division
• Post ganglionic neurons are situated in
sympathetic ganglia .
• Organs supplied - visceral organs like heart,
lungs, viscera , glands , smooth muscles .

5. Sympathetic Division
• Divisions of sympathetic ganglia -
• 1 - Paravertebral or sympathetic chain ganglia .
• 2 - Pre vertebral or collateral ganglia .
• 3 - Terminal or peripheral ganglia .

6. Paravertebral chain ganglia
• These are arranged in a segmental fashion along
the anterolateral surface of vertebral column .
• The ganglia on either side of the spinal cord are
connected with each other by longitudinal fibres
to form sympathetic chains .
• Both the chains extend from skull to coccyx .

7. Paravertebral chain ganglia
• There are 4 groups of ganglia
• 1 - Cervical ganglia
• 2 - Thoracic ganglia
• 3- Lumbar ganglia
• 4 - sacral ganglia

8. Cervical Ganglia
• 8 Cervical ganglia arranged in 3 groups
• 1 - Superior Cervical ganglia - it is largest
ganglion of the autonomic nervous system, formed
by fusion of upper four cervical ganglia .
• It receives pre ganglionic fibres from first thoracic
spinal segment (T1)via white rami .
• The postganglionic fibres from this ganglion supply
blood vessels, glands .

9. Cervical ganglia
• Sends some fibres to heart through superior
cervical sympathetic nerve and cardiac plexus.
• Middle cervical ganglion - formed by 5th & 6th
cervical ganglia.pre ganglionic fibres T1 segment
, and post ganglionic fibres supply - sweat glands
, thyroid and parathyroid glands
• Also sends fibers to heart through middle cervical
sympathetic nerve and cardiac plexus .

10. Inferior cervical ganglion
• It is formed by fusion of 7th & 8th cervical ganglia ,
• First thoracic ganglion fuses with inferior cervical
ganglion forming stellate ganglion .
• Receives pre ganglionic fibers from T1 segment .
• Sends post ganglionic fibres to heart through inferior
cervical sympathetic nerve and cardiac plexus
• Also forms the plexus around subclavian artery.

11. Thoracic ganglia
• There are 12 thoracic ganglia on each side .
• Receives pre ganglionic fibers from the thoracic
segments of spinal cord .
• Post ganglionic fibres distributed to visceral
organs in the thorax and abdomen .

12. Lumbar ganglia
• There are 5 lumbar ganglia .
• Pre ganglionic fibres arise from 1st and 2nd
lumbar spinal segments .
• Post ganglionic fibres distribute to thorax and
abdomens visceral organs .

13. Sacral ganglia
• There are 5 sacral ganglia .
• Receives pre ganglionic fibers from L1 and L2 .
• Post ganglionic fibers distribute to blood vessels and
sweat glands of lower limbs .
• Coccygeal ganglion relieves fibres from L1 and L2
segments .
• Post ganglionic fibres are distributed to pelvic region
and abdominal viscera .

14. Prevertebral or colateral
ganglia
• Situated in thorax , abdomen and pelvis in relation to
Aorta , they are -
• 1 - Celiac ganglion
• 2 - Superior mesenteric ganglion
• 3 - Inferior mesenteric ganglion
• Pre gang. - arise from T5 to L2
• Post gang. - supply - visceral organs of thorax , abdomen,
pelvis .

15. Terminal or Peripheral
ganglia
• Situated close to organs enervated by them -
bronchi, heart , pancreas , urinary bladder .

16. Parasympathetic Division
• It is also called as Craniosacral out flow - fibres
arise from brain and sacral segment .
• Parasympathetic division in brain stem
innervates the blood vessels of neck ,head &
many thoraco lumber visceral organs .
• Sacral segments of spinal cord innervates
smooth muscles of liver , spleen , kidneys ,
large intestine , bladder,genitalia .

17. Parasympathetic division
• Cranial nerves
• 1 - Oculomotor nerve - III nerve
• 2 - Facial nerve - VII nerve
• 3 - Glossopharyngeal nerve - IX nerve
• 4 - Vagus nerve - X nerve

18. Parasympathetic division
• Sacral out flow fibres arise from S2 to S4
segments of spinal cord .
• Pre ganglionic fibres arise from ….
• 1- Tectal or Mid brain level
• 2 - Bulbar level or Bulbar outflow
• 3 - Sacral outflow

19. Parasympathetic division
• Post ganglionic neutrons are situated with in the
organs or close to the organs innervated by
these nerves .
• Tectal or Midbrain level - Edinger - Westphal of
III cranial nerve nerve gives rise to fibres and end
in the ciliary ganglion
• Post ganglionic fibres from here supply
sphincter pupilae and ciliary muscle .

20. Bulbar level or Bulbar outflow
• From Medulla oblongata fibres of VII , IX , X cranial
nerves arise .
• VII nerve pre ganglionic fibres end in sphenopalatine
ganglion and submaxillary ganglion .
• Post ganglionic fibres from sphenopalatine ganglion
supply lacrimal and nasal glands .
• Fibres from submaxillary ganglion supply sublingual
and submaxillary glands .

21. Bulbar level or Bulbar outflow
• IX cranial nerve pre ganglionic fibers synapse
with neurons of Otic ganglion , post ganglionic
fibres from otic ganglion supply parotid gland .
• X cranial nerve preganglionic fibers terminate in
the ganglia which is near to the organs ,the post
ganglionic fibres from the ganglia supply the
organs .

22. Sacral outflow
• The preganglionic fibres arise from anterior gray
horn cells of 2nd , 3rd , & 4th sacral segments of
spinal cord and from the pelvic nerve
• Fibres end on the post ganglionic neutrons of the
organs they supply - rectum , colon ,bladder,
internal sphincter , urethra and visceral
organs .

23. Functions of ANS
• Concerned with regulation of functions which are
beyond voluntary control .
• Almost all visceral organs are supplied by both
divisions and two divisions produce antagonistic
effects on each organ .

25. Neurotransmitters of ANS
• Fibres of ANS perform their functions through
different neurotransmitters .
• Sympathetic fibers - 1- pre ganglionic fibres -
Acetylcholine
• 2 - post ganglionic noradrenergic fibres -
Noradrenaline
• 3 - post ganglionic cholinergic fibres - Ach .

26. Neurotransmitters of ANS
• Parasympathetic fibers -
• 1 - Pre ganglionic fibres - Ach .
• 2 - Post ganglionic fibres - Ach.
• Acetylcholine - Synthesis - in the cholinergic nerve
endings axoplasm and stored in vesicles .
• Acetyl Coenzyme A combines with choline in presence
of the enzyme choline acetyltransferase to form Ach .

27. Fate of Ach
• Action of Ach is very short .
• Immediately after releasing from vesicle , gets
hydrolysed into acetate and choline by the
enzyme Acetylcholinesterase .

28. • Bibliography
• Ganongs Review of Medical Physiology - Kim E.Barret et
all .
• Comprehensive Textbook of Medical Physiology - G.K.Pal
• Concise Physiology by K . Sambulingam

29. • Thank you