The sympathetic innervations of the ventricles of the heart arise in spinal levels

The sympathetic innervations of the ventricles of the heart arise in spinal levels

• A. T1-T2
• B. T3-T4
• C. T5-T6
• D. C8-T1

Answer: (A)

The ventricles receive sympathetic input from the upper part of the thoracic spinal cord. Preganglionic neurons located in that region send fibers into the sympathetic chain and synapse in the upper chest ganglia. The postganglionic fibers then travel with the cardiac nerves to reach the heart, including the ventricles, where they increase contractility and support higher heart rate during sympathetic activation. This explains why sources point to the upper thoracic levels as the origin of ventricular sympathetic innervation. Lower thoracic, cervical-only routes, or far lower levels do not provide the primary ventricular sympathetic input.

The ventricles receive sympathetic input from the upper part of the thoracic spinal cord. Preganglionic neurons located in that region send fibers into the sympathetic chain and synapse in the upper chest ganglia. The postganglionic fibers then travel with the cardiac nerves to reach the heart, including the ventricles, where they increase contractility and support higher heart rate during sympathetic activation. This explains why sources point to the upper thoracic levels as the origin of ventricular sympathetic innervation. Lower thoracic, cervical-only routes, or far lower levels do not provide the primary ventricular sympathetic input.