Which system consists of the brain and spinal cord?

The Central Nervous System is comprised of the brain and spinal cord, serving as the primary control center for processing information and coordinating activity throughout the body. It is responsible for receiving sensory input, integrating that information, and generating responses, which allows for actions such as movement, thought, and emotion.

In contrast, the Peripheral Nervous System encompasses all the nerves outside the brain and spinal cord, connecting them to limbs and organs; it plays a different role in the overall nervous system by facilitating communication between the Central Nervous System and the rest of the body. The Sympathetic Nervous System is a subset of the Autonomic Nervous System and is primarily involved in the body's 'fight or flight' responses, regulating involuntary functions like heart rate and digestion. The Autonomic Nervous System itself manages involuntary bodily functions and consists of both sympathetic and parasympathetic divisions, but it does not include the brain and spinal cord. Thus, the designation of the Central Nervous System specifically relates to the key structures essential for higher-level brain functions and spinal cord reflexes.