ABSTRACT
Sympathetic fibres from the CNS traverse the spinal cord and synapse in the sympathetic chain, and in cervical and paravertebral ganglia. Efferent fibres from these ganglia provide a rich network of postganglionic nerve endings innervating the atria, ventricles, sinus, and atrioventricular nodes. The parasympathetic (vagal) fibres synapse in ganglia in the heart and innervate the atria, sinus, and atrioventricular nodes, with a few fibres also supplying the ventricles.
