Cardiac nerves primarily originate from the cervical and upper thoracic ganglia, which are part of the sympathetic nervous system.
These nerves play a crucial role in regulating heart function. Here's a breakdown of their origins and pathways:
Sympathetic Cardiac Nerves:
- Origin: The majority of sympathetic cardiac nerves arise from postganglionic neurons located in the cervical ganglia (superior, middle, and inferior cervical ganglia) and the upper thoracic ganglia (also known as the stellate ganglia).
- Pathways: From these ganglia, the sympathetic fibers travel along the great arteries towards the heart.
- Destination: They ultimately join the cardiac plexus, which is located dorsal and caudal (behind and towards the tail) to the heart. This plexus then distributes the sympathetic nerves to various regions of the heart.
- Function: Sympathetic nerves generally increase heart rate, contractility (force of contraction), and conduction velocity.
In summary, cardiac nerves, particularly the sympathetic nerves that influence heart rate and contractility, originate from specific ganglia in the neck and upper chest.
