1. Autonomic Nervous System
Chad Byworth
Reference: Material from lecture Autonomic Nervous System, Dr R Tunstall

2. which have these effects...
What is the ANS?
The autonomic nervous system allows for the self-regulation of the body viscera, it is split into the...
Sympathetic Nervous System Parasympathetic Nervous System
which have these effects...
Raises heart rate
Increases force of contraction
Constricts most blood vessels
Slows GI transit
Constricts sphincters
Bronchodilates
Increase sweating
Dilates pupil (mydriasis)
Secretion of seminal fluid/movement of sperm
Slows heart rate
(no effect on force)
Relaxes blood vessels
Speeds up GI transit
Relaxes sphincters
Increases salivation
Bronchoconstricts
Constricts pupil (miosis)
Erection

3. ANS fibres are classified as pre- and post-ganglionic
Preganglionic
Target
Peripheral ganglion
Brainstem nucleus /
Cell body in lateral horn
What is this portion of the spinal cord?
Lateral horn
Autonomic
(only seen T1-L2 & S2-4)

4. Sympathetic Nervous System
Sympathetic supply arises from the...
Sympathetic Chain
How are sympathetics to the head supplied?
Sympathetics to the head arise from the chain
continuing to the base of the skull.
Sympathetic nerves exit the CNS at...
T1 - L2
What would damage at this level result in?
Damage at the level of the L1 vertebral body and below should not affect the sympathetic supply. However parasympathetic outflow to the pelvis will be disrupted.

5. Sympathetic Nervous System
Sympathetics to the head come from the sympathetic chain continuing up to the base of the skull. There are 3 ganglia in the neck, from here the supply continues alongside arteries and cranial nerves.
Run to pterygo-palatine ganglion from which they are distributed with CN V
Plexus
around ICA
CN VII
Sup.
Cervical
Ganglia
Forms deep petrosal nerve which joins parasympathetic greater petrosal nerve

6. Patient Case
What signs can you see on this patient? What else might you expect to see?
Miosis (pupillary constriction)
Partial ptosis
Anhydrosis (lack of sweating)
Vasodilation
What is this condition called? What has happened?
Horner’s Syndrome
Loss of sympathetic supply to one side of the head
What could cause this?
Pancoast Tumour Iatrogenic
Base of Skull Tumour Trauma
Lymphadenopathy

7. Parasympathetic Nervous System
Parasympathetic supply arises from...
CN III
CN VII
CN IX
CN X
4 cranial nerves
Pelvic splanchnic nerves
From S2-4 Spinal nerves
3 spinal nerves

8. Parasympathetic Nervous System
Parasympathetic post-ganglionic fibres emerge from...
Cranial nerves III, VII, IX & X
...and travel with...
Cranial nerve V
Loss of parasympathetics to the head can lead to loss of the...
Pupillary light reflex, this is because there is unopposed sympathetic
action leading to full dilation of the affected pupil.

9. Neurotransmitters α or β
What are the 2 principal neurotransmitters in the peripheral nervous system?
Acetylcholine and Noradrenaline
Complete with each neurotransmitter and receptor
CNS
ACh
Somatic efferent
Nicotinic
ACh NA
Sympathetic
α or β
Nicotinic
ACh
ACh
Parasympathetic
Nicotinic
Muscarinic

10. Spinal nerve
Virginia Lam

11. What are they? Part of peripheral nervous system
Communication between periphery and CNS
Peripheral nervous system: Spinal and cranial nerve, autonomic nervous system and somatic sensory and motor nerve

12. Where are they? from?
Arise through numerous rootlets from dorsal and ventral surface of spinal cord
The dorsal and ventral root of spinal nerve will combine and form dorsal root ganglion, and extend to be spinal nerve
Where do they emerge from in the vertebral column?
Intervertebral foramen
Dorsal root carries sensory fibre
Ventral carries motor
Emerge through intervertebral foramen
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13. How they are named? A little tricky! Or may be not
31 pairs of spinal nerve
8 pair of cervical
12 thoracic
5 lumbar
5 sacral
1 coccyx
Cervical spinal nerves exit …… corresponding vertebrae
What happen in thoracic and the following?
After T1 level, all spinal nerve exit below the corresponding vertebrae

14. How spinal nerves distribute?
Dorsal and ventral rami
Plexus

15. Ramus Branch off after dorsal root ganglion
Both are mixed (somatic motor & sensory, visceral sensory and autonomic)
Innervation:
Dorsal ramus:
deep muscle and skin of the back
Ventral ramus:
muscle and structure of upper and lower limbs, and skin of anteriolateral of the trunk

16. Plexuses Plexuses = network of axon Principle plexus: Cervical
Brachial
Lumbar
sacral
coccygeal

17. Why bother? Lumbar puncture Anaesthesia Pathology Epidural Spinal
Caudal
Pathology
IV Disc prolapse
Cervical/lumbar spondylosis (osteroarthritis)
Trauma to nerve or plexuses
Herpes zoster (dermatonal distribution in thorax)

18. For IV disc prolapse, the damage will be one level below