CBSE Class 10 Science 2020 · Paper 31/C/1 · Question 26

Central nervous system: the brain and the spinal cord. Peripheral nervous system: the nerves that connect the CNS with the rest of the body, that is, the cranial nerves arising from the brain and the spinal nerves arising from the spinal cord. Protection: the brain lies inside a bony box, the cranium (skull), and within it is contained in a fluid-filled balloon (membranes and fluid) that absorbs shocks; the spinal cord is enclosed and protected by the vertebral column (backbone). Spinal cord injury: the signals that have to pass through the injured part of the cord are disrupted in both directions: sensory signals from the receptors of the body below the injury to the brain (so feeling there is lost), motor signals from the brain to the muscles below the injury (so voluntary movement there is lost), and the reflex actions whose reflex arcs pass through the damaged part of the cord.