Which structure is a key component of the central nervous system?

The spinal cord is a key component of the central nervous system (CNS) because it serves as the main pathway for transmitting information between the brain and the rest of the body. The CNS is primarily composed of the brain and spinal cord, which work together to process and coordinate the body's functions, including sensory input, motor output, and reflex actions.

In contrast, peripheral nerves are part of the peripheral nervous system, which connects the CNS to limbs and organs. Muscles play a role in movement but are not part of the nervous system itself. Endocrine glands are involved in hormone production and regulation but do not contribute to the central nervous system's structure. Understanding the roles of these different systems and structures is vital in grasping the overall organization and functionality of the human body.