Fight or flight

• the fight or flight response is a sequence of activity within the body that is triggered in response to stress, enabling us to react quickly to life threatening situations
• the stress response is triggered by the amygdala, an area of the brain which associates sensory inputs with emotions. the amygdala sends a distress signal to the hypothalamus
• hypothalamus activates the sympathetic nervous system. the SNS activates the adrenal medulla, causing the adrenal medulla to realise adrenaline
• adrenaline causes an increase in heart rate, breathing, blood pressure, so more oxygen reaches the heart and muscles. it also triggers release of glucose into the blood to supply energy, but inhibits digestion during the emergency
• when the threat has passed, the parasympathetic nervous system restores heart rate and blood pressure to normal and allows digestion to restart