What is the nervous system designed to do? Nerves make the arms and legs move. Nerves make the heart beat and the lungs breathe. Ultimately, the entire nervous system is designed to keep the body alive. That is its most primal function. If a lion is chasing, the body runs. If the hand touches something hot, it jerks away. Just like a built-in alarm system, this system of nerves will alert the body to danger and trigger automatic protective responses. Normally, this system works beautifully and...