What structures compose the central nervous system (CNS)?

The central nervous system (CNS) is composed of the brain and the spinal cord. These two structures are integral to the CNS as they serve vital functions in processing and transmitting information throughout the body. The brain is responsible for higher-level functions such as thinking, memory, and sensation, while the spinal cord acts as a major conduit for signals between the brain and the rest of the body, coordinating reflexes and motor control.

Options that denote all nerves in the body, peripheral nerves only, or all muscles and tissues do not accurately represent the components of the CNS. The peripheral nervous system (PNS), which includes all the nerves outside of the brain and spinal cord, operates alongside but distinct from the CNS. Muscles and tissues are part of the broader context of the nervous system but do not belong to the CNS itself. Therefore, recognizing that the CNS specifically consists of the brain and spinal cord is crucial for understanding its role in the nervous system.