Answer
Ventricular myocardium receives innervation from the sympathetic branch of the autonomic nervous system (ANS), only.
Work Step by Step
Sympathetic nerves from the medulla oblongata enter the spinal cord and. The cardiac accelerator nerve leaves the spinal cord at the thoracic region and innervates the SA node, the AV node and the myocardium. The sympathetic neurons release norepinephrine which enhances the entry of Ca++ ions through voltage-gated ion channels. The influx of Ca++ ions increases the force of the contraction of the ventricular myocardium with a consequent increase in volume of blood ejected during ventricular systole.
