Sympathetic Nervous System's Flight or Fight Response

   

TABLE 36—2 Sympathetic Nervous System’s Fight-or—F ight-Response

Physiologic Response Physiologic Rationale
Increased heart rate To deliver needed oxygen rapidly
Increased respiratory rate To increase tidal volume, thereby increasing available oxygen
Increased glycolysis, gluconeogenesis, mobilization of free To increase availability of glucose for energy
fatty acids :
Decreased urine output To conserve fluid volume; to return more blood volume
' to cardiovascular system to increase volume and blood
pressure
Decreased blood flow to internal organs (e.g., kidneys, To allow more blood flow to more vital organs (e.g., heart and
gastrointestinal tract, liver) lungs)
Decreased intestinal peristalsis To shunt blood to vital organs; no need for digestion as body

energy is redirected to lifesaving measures

Cool skin Alpha receptors produce peripheral vasoconstriction to shunt
blood to more vital organs

Diaphoresis To release heat as a by—product of metabolism
—