L1.1 ANS

Question 1

Pathway of the somatic neurons

Answer 1

Sensory - afferent

Motor - efferent

Question 2

PS

Answer 2

• Cranio-sacral
  
  • Long pre-ganglionic neuron → post ganglionic neurons (close to target organs)
    
    • Most organs receive PS innervation from vagus N (10th cranial N)

Question 3

Sym

Answer 3

• Thoraco-lumbar (originates in LAT horn, leaves through ventral root)
• Short pre-ganglionic neuron, long post-ganglionic neuron (Synapses close to CNS)
  
  • T1-4 (Upper organs) → Synapse in sym trunk
  • Abdomen nerves → Goes through sym trunk but synapses outside trunk

Question 4

Sym pathway

Answer 4

• White rami (distal), Grey rami (prox & contains only post-ganglionic neurons)
  
  • Synapses at rami gives off 3 pathways:
    
    • Ascending → synapses → head viscera
    • Straight → Synapses → Abdomen vis
    • Straight → no synapses → thoracic viscera

Question 5

Visceral afferent neuron

Answer 5

• Not somatic nor ANS
• Provide sensory info to viscera
• Follows sym pathways back to CNS, but could also follow PS (vagus) back to CNS

Question 6

Visceral afferent neuron’s relationship to referred pain

Answer 6

• Visceral neurons end up in the same spinal segment as nerves supplying the skin (dermatomes)