Pulmonary Vein Ganglia and the Neural Regulation of the Heart Rate

The sympathetic and parasympathetic branches of the autonomic nervous system exert fine-tuned reciprocal influences on the heart. Sympathetic stimulation increases heart rate, electrical conductivity, and contractility, whereas in general, parasympathetic stimulation produces opposing inhibitory effects. However, the cardiac regulation driven by the autonomic nervous system is complex. In fact, the electromechanical function of the heart is subject to the influence of two separate autonomic nervous systems: the extrinsic cardiac nervous system (ECNS) and the intrinsic cardiac nervous system (ICNS). Here, we will explore the influence of the intrinsic nervous system on the regulation of heart rate.