Fight or Flight

• Fight or flight - response to a stressor generated by the automatic nervous system through the sympathetic branch
• Fight or flight - Physiological response that humans undergo when they perceive or experience a threat which lasts about 30 minutes
• The hypothalamus must recognise the threat
• The hypothalamus activates the sympathomedullary (SAM) pathway, which sends a signal that stimulates the adrenal glands
• The adrenal glands release adrenalin and noradrenaline into the bloodstream, which regulate various bodily processes to prepare for fight or flight
• Effects of adrenaline :

  • Pupil dilation - allow more light in to see the threat more clearly
  • Increased heart rate/ blood pressure - quickly get more oxygen to the muscles
  • Increased respiration rate - more oxygen entering the body to be used for energy
  • Reduced activity in digestive system - body is able to use the energy for other functions
• Fight or flight is an unsustainable use of energy so the parasympathetic nervous system kicks in to return the body to its 'normal' state; this is known as the rest and digest response
• The 'normal' state of the body is known as homeostasis