The superior cardiac nerve is a cardiac nerve and extends from the superior cervical ganglion to the cardiac plexus. It is part of the sympathetic autonomic nervous system and primarily influences cardiac function. Certain drugs and medications can enhance (sympathomimetics) or attenuate (sympatholytics) its effects.
What is dre superior cardiac nerve?
The human body has a total of three cardiac nerves that connect the vital organ to the sympathetic nervous system. The superior cardiac cervical nerve is one of them and runs slightly differently in the two halves of the body. In its entirety, the sympathetic nervous system (sympathetic nervous system) forms the activating part of the autonomic/autonomic nervous system. In relation to the heart, it influences heartbeat, tension and relaxation of cardiac muscle fibers, conduction of excitation and threshold of the cells involved.
Anatomy and structure
The superior cardiac nerve does not run symmetrically on both sides in the body because the heart is slightly displaced to the left in the thorax. In this half of the body, it terminates at the base of the heart (basis cordis), which is opposite the apex of the heart. At the base of the heart, the superior cardiac nerve joins a plexus of nerves called the cardiac plexus. This cardiac plexus is acted upon not only by sympathetic nerve fibers, but also by parasympathetic ones. The superior cardiac nerve comes from the direction of the aortic arch and further up from the area of the left common carotid artery. There it traces its path in front of the blood vessel at the base of the neck. The superior cardiac nerve originates in the superior cervical ganglion. This ganglion is a nerve node where various nerve fibers converge and the neuron density is particularly high. In the right half of the body, on the other hand, the cardiac nerve runs from the cervical superciliary ganglion along behind the aortic arch to the heart and also transmits neuronal signals to the cardiac plexus. In addition, some fibers of the superior cardiac nerve lead to the middle cervical ganglion or middle cervical ganglion.
Function and Tasks
The function of the superior cardiac nerve is to transmit signals, primarily connecting the superior cervical ganglion to the cardiac plexus or plexus at the base of the heart. There, the nerve relays its signals to the deep part of the cardiac plexus; this part is responsible for controlling the organ. As one of the three cardiac nerves, the superior cardiac plexus is vital. In the cardiac plexus, information arrives not only from the cervical ganglion via the superior cardiac nerve, but also from the medium cervical ganglion via the median cardiac nerve and from the stellate ganglion via the inferior cardiac nerve. These three pathways are part of the sympathetic nervous system; the parasympathetic supply to the cardiac plexus is via part of the vagus nerve, which also performs depth perception tasks. The sympathetic nervous system influences the heartbeat, tension and relaxation of the cardiac muscle fibers (contraction), excitation conduction and stimulus threshold. For the superior cardiac nerve to perform its function, it relies on two crucial mechanisms: electrical transmission of information within the nerve fiber and biochemical transmission at the junctions with other nerve cells. Within a single nerve fiber, the electrical action potential can propagate in only one direction. The reason for this is the regeneration time of the nerves, which must first recover after the electrical charge by restoring the original state of charge. If the electrical impulse leaves the first fiber section and moves to the second, the first section is blocked by the previous change in charge; therefore, the action potential can only continue to propagate in one direction and travels to the third section. Biochemical transmission at the [8synapses]], on the other hand, relies on messenger substances (neurotransmitters). The electrical signal converts into a chemical one at the synapse and crosses the synaptic cleft to stimulate the subsequent nerve cell.In the sympathetic nervous system, the neurotransmitters are acetylcholine (at preganglionic neurons) and norepinephrine (at postganglionic neurons).
Diseases
In the setting of heart transplantation, the connection of cardiac nerves to the transplanted organ presents a challenge. At the functional level, certain drugs and medications can affect cardiac function by interfering with the sympathetic nervous system; in this context, the superior cardiac cervical nerve either receives altered nerve signals or the agents alter its own transmission of information. In part, however, these substances also act on muscle cells and other tissues. Substances that enhance the effect of the sympathetic nervous system are called sympathomimetics and act either directly or indirectly. Direct sympathomimetics act as neurotransmitters themselves and trigger the same reaction at the receptors of cells as the actual messenger substance. In contrast, indirect sympathomimetics reduce the rate of neurotransmitter degradation, allowing them to occupy receptors longer. Stimulant drugs such as cocaine and amphetamines are well-known examples of indirect sympathomimetics. Sympatholytics are also known as adrenolytics. Like sympathomimetics, sympathetic inhibitors can be divided into direct and indirect agents. One group of drugs that belongs to the sympatholytics are alpha blockers, where the suffix “alpha” refers to the type of receptors they act on. In medicine, they are used primarily in the treatment of diseases of the cardiovascular system; a typical application is hypertension. In addition, alpha blockers may be considered for patients with benign prostate enlargement.
