The neurological system affects all parts and functions of the body through nerve stimulation. Nerves also control the sensation and perception of pain. While pain can be described in a variety of ways, it is essentially labeled according to its duration and source. As an advanced practice nurse evaluating a patient, you need to consider the following questions: Does the pain quickly come and go, or is it persistent and ongoing? Does the pain arise at the source of injury or in another location? In this Discussion, you compare three common types of pain—acute, chronic, and referred.