Compare and contrast the functions of the sympathetic and parasympathetic nervous system. What does the current scientific evidence indicate in regard to one's ability to consciously control functions normally controlled by the autonomic nervous system?

The autonomic nervous system is divided into the sympathetic and the parasympathetic tracts. The sympathetic nervous system responds in situations that are considered emergencies to ready the body for action. The parasympathetic follows with signals that indicate the body should relax. Recent studies have shown that humans have some control over the autonomic nervous system, such as learning to moderate the severity of high blood pressure, migraine headaches, etc. through biofeedback.