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Context: The vagus nerves supply the neck viscera, heart, lungs and gastrointestinal tract. They join around the oesophagus to form the oesophageal plexus.


Question: Would damage to one vagus nerve in the neck have significant impact on heart rate and gastrointestinal tract function?


Thoughts: If the heart and GIT lie below the oesophageal plexus, which then continue in the inferior direction towards the cardiac and gastric plexuses, then surely a major functional failure in either the heart or GIT would require damage to both vagus nerves (?). I'm trying to make sense of the effect of their fusion, and whether or not this provides a compensating mechanism in the event that one of the two nerves is damaged.

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    $\begingroup$ It depends how they're damaged. Pressed on so that they fire continuously and simply severed so that no firing happens have different results. $\endgroup$ – Resonating Oct 30 '15 at 16:26
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    $\begingroup$ @Hernandez - it also depends "where" they are damaged. There are branches that we routinely encounter during stomach operations that, if we damaged, would have very different effects compared to damaging the vague as it descends through the neck in the carotid sheath. More distal injury (i.e. further away from the brain) would likely be less debilitating than more proximal injury. $\endgroup$ – Vance L Albaugh Nov 24 '15 at 22:45
  • $\begingroup$ @Hernandez - how high of a injury in the neck or how low of an injury in the neck? $\endgroup$ – Vance L Albaugh Nov 25 '15 at 5:23
  • $\begingroup$ I was thinking more of damage at the level of the neck. I guess if it occurs before the nerves join to supply fibres to the cardiac and coeliac plexi, parasympathetic functions relating to heart activity and the GIT would remain relatively untouched. Perhaps only the more superior pharyngeal innervations would be affected by such damage. $\endgroup$ – Hernandez Nov 25 '15 at 5:38
  • $\begingroup$ To qualify that further, I was thinking of damage above the level of the C6 vertebral body. $\endgroup$ – Hernandez Nov 25 '15 at 5:45
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Would damage to one vagus nerve in the neck have significant impact on heart rate and gastrointestinal tract function?

Not that much, because fibers from both sides are fused, so each nerve carries about a 50% of fibers originated from the one side and about 50% from the contro-lateral. Consider that fibers are rewired after each plexus.

References:

wikipedia page about vagus nerve

wikipedia category about vagus nerve

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