Fight or Flight Response and Adrenaline

• Fight of flight happens in response to a perceived threat, harmful event or attack
• There a are two systems involved in the stress response; acute stressors (sudden attack) and chronic stressors (stressful job)
• When faced with attack, what is mobilised?

  The amygdala
• When faced with threat, the Amygdala sends a distress signal to the hypothalamus then communicates with the rest of the body through the sympathetic nervous system
• Response to acute stressors

  The hypothalamus triggers the sympathetic nervous system. The SNS sends a signal to the pituitary gland which stimulates the adrenal medulla to release adrenaline into the bloodstream. Adrenaline circulates the body, causing physiological changes (increased heart rate, increased blood pressure and pupil dilation. Triggers the release of blood sugars, to give the body energy for fight or flight. Once threat has passed, the parasympathetic nervous system is activated. (Slowing heart rate and starting digestion)
• Chronic stressors are activated when the threat is perceived to be on going
• What kicks in if the brain perceives the threat to be chronic?

  If the brain perceives the threat to be ongoing, a second system, kicks in called the hypothalamic pituitary adrenal axis (HPA)
• Response to Chronic Stressors

  If the bran perceives the threat to be ongoing, the hypothalamic pituitary adrenal axis kicks in. The Hypothalamus releases a chemical messenger called Corticotrophin releasing hormone (CRH) into the bloodstream. CRH arrives at the pituitary gland and triggers the release of ACTH (adrenocorticotrophic hormone). ACTH stimulates the adrenal cortex to release stress related hormones such as cortisol. Cortisol has positive effects (quick burst of energy) and negative effects (low immune system and cognitive impairment) This helps us deal with the ongoing stressors.
• If stress response is constantly activated it can lead to heart disease
• Stress response can be beneficial. Van Dawans et all found that acute stress can lead to greater co-operative and friendly behaviour. this explains why humans are sociable beings
• Outline the role of Adrenaline in the fight or flight response

  Adrenaline is released from the adrenal medulla in response to the activation of the sympathomedullary pathway. Adrenaline triggers the body for fight or flight, it does this by increasing the oxygen to the brain for rapid response planning and increases the blood/oxygen supply to skeletal muscles for physical action