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INNERVATION OF HEART HEART ANATOMY

The innervation of the heart is given by autonomic nerve fibers from the vagus and sympathetic trunks. Sympathetic innervation

preganglionic sympathetic fibers originate from dorsal levels I to IV (and sometimes the V and VI) of the spinal cord. Synapse in the cervical ganglia and dorsal.

Sympathetic Trunk Ganglia: formation of cardiac sympathetic branches to the heart
postganglionic sympathetic fibers to the heart, are driven by cardiac branches of the cervical and dorsal portions of the sympathetic trunk, these fibers end in sinoatrial and atrioventricular nodes in cardiac muscle fibers and dilation of the coronary arteries, including both atria and ventricles. The activation of these nerves results in: cardiac acceleration, increased strength of heart muscle contraction and dilation of the coronary arteries. Branches
heart: The cardiac branches are extremely variable in its topography and direction, and are grouped according to their level of origin as follows:
cervical cardiac branches, with higher frequency and a half originate in the cervical sympathetic trunk in ganglia, or both, and generally joined with branches of the vagus nerve, pharyngeal plexus, throat, carotid and thyroid. After all the branches down in front of or behind the aortic arch and enters the cardiac plexus. The superior cervical sympathetic nerve does not receive sensory input from the area.
cervicothoracic cardiac branches, also called lower cervical, originate from the cervicothoracic ganglion (stellate ganglion) and is usually joined by cervicothoracic cardiac branches of the vagus nerve (sometimes there is a branch of the phrenic nerve that joins.) Then the group of nerves goes ahead or behind the aortic arch to the cardiac plexus.
The thoracic cardiac branches: originate in the fourth or fifth upper thoracic sympathetic ganglion and together with the thoracic cardiac branches of vagus nerve (in relationship to the left recurrent laryngeal nerves), go directly to the cardiac plexus, especially the back walls of the atria .

parasympathetic innervation

Vagus Nerve: Primary visceral parasympathetic component, forming the cardiac plexus.
preganglionic parasympathetic fibers in the vagus nerves (originating in the medulla oblongata, the dorsal nucleus (parasympathetic) which receives input from the hypothalamus and the glossopharyngeal nerve) are conducted as cervical and thoracic cardiac branches to the ganglion cells in the cardiac plexus (below the tracheal bifurcation in the adventitia of the pulmonary trunk) or subepicardial, where they synapse.
parasimpátcias postganglionic fibers innervate the Keith and Flack node (node) of Aschoff and Tawara (atrioventricular) and coronary arteries. The activation of these nerves causes a reduction in the frequency and force of myocardial contraction and vasoconstriction of the coronary arteries.

afferent autonomic innervation

Most organs are innervated only by autonomic nerves. Therefore, it appears that visceral pain is driven by afferent autonomic nerves. Visceral pain is diffuse and poorly localized, while the somatic pain is intense and localized. Visceral pain is often referred to cutaneous areas innervated by the same segments of the spinal cord to the viscera painful. The explanation of referred pain is not known. One theory is that nerve fibers from the viscera and the dermatome ascend in the central nervous system along a common pathway and that the cortex is unable to distinguish between sites of origin. Another theory is that, under normal conditions, the bowel does not give rise to painful stimuli, while the area of \u200b\u200bskin repeatedly receives noxious stimuli. Since both afferents enter the spinal cord in the same segment, the brain interprets the information as coming from the skin rather than the viscera.