The three cardiac nerves are the superior cardiac nerve, the middle cardiac nerve, and the inferior cardiac nerve.
These nerves are part of the autonomic nervous system and play a crucial role in regulating heart function. They originate from the cervical ganglia of the sympathetic trunk in the neck and travel to the cardiac plexus, a network of nerves located near the base of the heart.
Here's a breakdown of each nerve:
-
Superior Cardiac Nerve (Nervus Cardiacus Cervicalis Superior): Arises from the superior cervical ganglion. It primarily carries sympathetic fibers to the heart, which generally increase heart rate and contractility.
-
Middle Cardiac Nerve (Nervus Cardiacus Cervicalis Medius): Originates from the middle cervical ganglion. It also contains sympathetic fibers and contributes to increasing heart rate and force of contraction.
-
Inferior Cardiac Nerve (Nervus Cardiacus Inferior): Stems from the inferior cervical ganglion (which is often fused with the first thoracic ganglion to form the stellate ganglion). Like the other two, it carries sympathetic fibers involved in cardiac stimulation.
In summary, the superior, middle, and inferior cardiac nerves are sympathetic nerves that contribute to the regulation of heart function by increasing heart rate and contractility. Their precise effects and distribution can vary slightly between individuals.
