The extrinsic cardiac nervous system
The extrinsic part of cardiac nervous system includes theĀ ganglia and
nerves en route to the heart. A ganglion is a cluster of neuronal cell
bodies outside the brain (1). In the ANS, while efferent axons from the
central nervous system to the ganglion are known as preganglionic nerve
fibers, efferent axons from the ganglion to the effector organ are
called postganglionic nerve fibers (1). Although ganglia of the
sympathetic division are located within the sympathetic chain or
paravertebral ganglia, ganglia of the parasympathetic division which are
called as either the intramural or the intrinsic ones are distributed
mainly within the epicardial area (3, 17, 18) (Figure 1). Thus,
parasympathetic postganglionic fibers tend to be shorter than
sympathetic ones. All extracardiac nerves access the epicardial neural
plexus as extensions of the extrinsic cardiac
plexuses.