What nervous system includes the brain and spinal cord?

The central nervous system is composed of the brain and spinal cord, making it the main control center for processing information and coordinating responses throughout the body. The brain serves as the primary hub for interpreting sensory information, making decisions, and directing actions. The spinal cord acts as a crucial pathway for transmitting signals between the brain and the rest of the body, facilitating reflexes and enabling communication across the nervous system.

In contrast, the peripheral nervous system encompasses all the nerves outside the central nervous system, functioning to connect the central nervous system with limbs and organs. The autonomic nervous system, which is a part of the peripheral nervous system, regulates involuntary bodily functions, such as heartbeat and digestion, while the somatic nervous system manages voluntary movements and relays sensory information to the central nervous system. These distinctions clarify why the central nervous system is specifically defined by its components, the brain and spinal cord.