The sympathetic nervous system is critical in maintaining the normal physiological function of the heart. Its dysfunction in pathological states may exacerbate the substrate for arrhythmias. Obviously, knowledge of its three-dimensional 3D structure is important, however, it has been revealed by conventional methods only to a limited extent. In this study, a new method of tissue clearance in combination with immunostaining unravels the 3D structure of the sympathetic cardiac network as well as its changes after myocardial infarction.
Autonomic Innervation of the Heart and Vasculature
The Role of the Autonomic Nervous System in Sudden Cardiac Death
Sympathetic nervous system , division of the nervous system that functions to produce localized adjustments such as sweating as a response to an increase in temperature and reflex adjustments of the cardiovascular system. Under conditions of stress , the entire sympathetic nervous system is activated, producing an immediate widespread response called the fight-or-flight response. This response is characterized by the release of large quantities of epinephrine from the adrenal gland , an increase in heart rate, an increase in cardiac output , skeletal muscle vasodilation, cutaneous and gastrointestinal vasoconstriction, pupillary dilation, bronchial dilation, and piloerection. The overall effect is to prepare the individual for imminent danger. The actions of the sympathetic nervous system occur in concert with other neural or hormonal responses to stress, including increases in corticotropin and cortisol secretion. In humans, chronic stress results in long-term stimulation of the fight-or-flight response, which leads to constant production and secretion of catecholamines e.
Sympathetic nervous system
The vagus nerves are paired but are normally referred to in the singular. It is the longest nerve of the autonomic nervous system in the human body. The ending part of vagus nerve is known as spinal accessory nucleus. Upon leaving the medulla oblongata between the pyramid and the inferior cerebellar peduncle , the vagus nerve extends through the jugular foramen , then passes into the carotid sheath between the internal carotid artery and the internal jugular vein down to the neck , chest , and abdomen , where it contributes to the innervation of the viscera , reaching all the way to the colon. The cell bodies of visceral afferent fibers of the vagus nerve are located bilaterally in the inferior ganglion of the vagus nerve nodose ganglia.
The autonomic nervous system cANS is essential for proper heart function, and complications such as heart failure, arrhythmias and even sudden cardiac death are associated with an altered cANS function. A changed innervation state may underlie part of the atrial and ventricular arrhythmias observed after myocardial infarction. In other cardiac diseases, such as congenital heart disease, autonomic dysfunction may be related to disease outcome.