Mr. Collins is a 60-year-old patient who was in a car accident earlier in the day. After an examination, the physician determines that Mr. Collins sustained no physical injuries, although the patient's blood pressure and heart rate are elevated. Mr. Collins reports that at the time of the accident he felt a high level of fear and he noticed that he had goose bumps and was sweating profusely. Currently, he reports feeling constipated. Explain the mechanics of Mr. Collins's physiological reaction to the stressful experience of an automobile accident and describe the division of the autonomic nervous system that is responsible for Mr. Collins's symptoms.