Which of the following structures is part of the central nervous system?

The spinal cord is an integral component of the central nervous system (CNS), which also includes the brain. The CNS is responsible for processing information and coordinating activities throughout the body. The spinal cord serves as a major pathway for transmitting signals between the brain and the rest of the body, allowing for reflex actions and sensory information processing.

In contrast, the plexus of nerves and peripheral ganglia are part of the peripheral nervous system (PNS), which connects the CNS to limbs and organs. Cardiac muscle, while crucial for the function of the heart, does not belong to the nervous system at all. Understanding the distinction between the central and peripheral nervous systems is fundamental to grasping the overall architecture and function of the nervous system.