Sympathetic impulses to the adrenal medulla increase their secretion of epinephrine and norepinephrine. These hormones work to prolong the sympathetic responses. When this occurs, blood is shifted from nonvital, vital parts of the body. Blood vessels of the skin, spleen, kidneys, and intestines constrict and those to the heart, skeletal muscles, lungs, and brain dilate. Respiration, heart rate, blood pressure, and the strength of cardiac contraction increase.
Skin becomes pale, pupils dilate, and sweat production increases.
Muscle tension rises, energy stores are mobilized which increases blood glucose. There will be a resulting decline in parasympathetic -activity, which will cause nausea, vomiting, and loss of appetite. This alarm reaction within the body will enhance or heighten the sensation of pain. Anxiety related to pain may play out with increased irritability, depression, withdrawal from outside interests, strained relations with family and friends, decreased sleep, and decreased appetite. Distrust and frustration of medical staff will increase.