Which part of the nervous system is composed of the brain and spinal cord?

• A. Peripheral nervous system
• B. Autonomic nervous system
• C. Somatic nervous system
• D. Central nervous system (CNS)

Answer: (D)

The central nervous system is the part of the nervous system that contains the brain and spinal cord. The brain serves as the main processing and decision-making hub, interpreting sensations, guiding thoughts, and coordinating movements. The spinal cord acts as the main conduit, carrying messages between the brain and the rest of the body, and it can also manage simple reflexes on its own. This arrangement distinguishes it from the peripheral nervous system, which includes all nerves outside the brain and spinal cord and connects the CNS to muscles, organs, and sensory receptors. Within the peripheral system, the autonomic division regulates involuntary functions like heart rate and digestion, while the somatic division handles voluntary movements and sensory information from the skin and muscles.