Central Nervous System

The central nervous system (CNS) is the part of the nervous system consisting of the brain and spinal cord. It serves as the body's main control center, processing information and coordinating activity; the brain handles conscious functions and homeostasis, while the spinal cord manages reflexes and links the brain to peripheral nerves.

• The CNS is protected by the skull (brain) and vertebral column (spinal cord), as well as three layers of membranes (meninges) and cerebrospinal fluid. This bony protection is a key difference between the CNS and the peripheral nervous system (PNS).
• Neurons in the CNS form networks for complex processing: the brain is responsible for higher functions (memory, emotion, decision-making) and regulating body systems, while the spinal cord can independently mediate simple reflexes (like the knee-jerk reflex).
• Damage to the CNS (e.g., spinal cord injury or stroke) is often serious because CNS neurons have limited ability to regenerate. This is why protecting the brain and spinal cord (e.g., wearing helmets, avoiding spine trauma) is critical.

• If a question asks "Which structures make up the central nervous system?" -> the answer is the brain and spinal cord.
• If a scenario mentions an injury "within the spinal column" or "inside the skull" affecting nervous tissue -> it's referring to the CNS (encased in bone), whereas nerves outside those areas belong to the PNS.
• If a question contrasts information processing in the brain/spinal cord vs signal transmission in nerves -> it's distinguishing the CNS (processing center) from the PNS (which carries information to/from the CNS).