Some elementary reflexes are local to the spinal cord, but voluntary muscle control requires the brain as do sensory perceptions. The cells that mediate all functions are nerve cells or neurons.... Axons carry signals downward from the brain and upward toward the brain. ... Pain is not always a symptom of injury to the spinal cord, but injury to nearby nerves sometimes causes sever pain. ... Destruction of sensory nerve fibers can lead to loss of sensations such as touch, pressure, and temperature; it sometimes also causes pain. ...

• Word Count: 1606
• Approx Pages: 6
• Grade Level: High School