Which structures comprise the central nervous system?

• A. Brain and spinal cord
• B. Spinal nerves
• C. Ganglia
• D. Cranial nerves

Answer: (A)

The central nervous system is made up of the brain and spinal cord, which act as the body's primary processing and command centers. The brain analyzes sensory input, stores information, and directs actions, while the spinal cord transmits signals between the brain and the rest of the body and handles many reflexes. Structures like spinal nerves, cranial nerves, and ganglia belong to the peripheral nervous system; they connect the CNS to muscles, glands, and sensory receptors, carrying information to and from the brain and spinal cord.