Parasympathetic division (coronary plexuses)

The parasympathetic division of the coronary plexuses can be considered in terms of:

• general visceral motor fibres:
  • derived from vagus nerve:
    • directly via superior and inferior cardiac branches
    • indirectly via recurrent laryngeal nerves
  • these are preganglionic fibres with their cell bodies in the dorsal motor nucleus of the vagus nerve
• they pass through the coronary plexus to synapse with ganglia within the heart wall e.g. the ganglia of the sinoatrial node
  • stimulation produces negative inotropy, chronotropy and coronary artery vasoconstriction
• general visceral afferent fibres:
  • originate in the walls of the carotid body and sinus
  • preganglionic fibres have their cell bodies in the inferior vagal ganglion
  • centrally synapse with the nucleus of tractus solitarius
  • involved with baroreceptor reflexes