Fight or flight

• 1. The body senses and becomes aware of a stressor in the environment.
• 2. Through sensory receptors and sensory neurons in the PNS, this information is sent to the hypothalamus in the brain which coordinates a response and triggers increased levels of activity in the sympathetic branch of the ANS.
• 3. Adrenaline is released from the adrenal glands, and is transported to target effectors, via the blood and through the action of the endocrine system.
• 4. This results in saliva production being inhibited and a greater breathing rate. This creates the physiological response needed to sustain the fight or flight response, whose adaptive purpose is to enable us to escape the stressor and so increase the likelihood of our survival.
• 5. Once the stressor is no longer a threat, the hypothalamus triggers less activity in the sympathetic branch and more activity in the parasympathetic branch decreasing the activity which was originally increased through the action of the sympathetic branch.