Paravertebral ganglia are clusters of nerve cell bodies located alongside the spinal column. They are part of the sympathetic nervous system, which is responsible for the body's "fight or flight" response. These ganglia form a chain known as the sympathetic trunk, extending from the base of the skull to the coccyx. These ganglia play a crucial role in transmitting signals that regulate various bodily functions, such as heart rate, blood pressure, and digestion. They receive input from the spinal cord and send out nerve fibers to target organs, helping to coordinate the body's response to stress and emergencies.