Autonomic nervous system

• Homeostasis

  • ANS is responsible for controlling homeostasis
  • Process where the body maintains a constant balanced state
  • E.g, levels of carbon dioxide are controlled through breathing
  • ANS controls vital gland, muscles and organs
• Automatic autonomic

  • ANS is not controlled by us
  • Actions such as breathing or heart rate are required for survival
• Two divisions

  • ANS is divided into sympathetic and parasympathetic nervous systems
  • One of them is always activated
  • Both of them cannot be activated at the same time
• Sympathetic nervous system

  • When the body is in a state of physiological arousal, preparing the body for fight or flight
• Parasympathetic nervous system

  • When the body is in a state of rest and digest as there is no threat to us
• When threatened, our sympathetic nervous system is activated. When resting, our parasympathetic nervous system is activated
• Fight or flight

  • Immediate physiological response of an animal when in danger
  • The body becomes physically ready to fight the threat or run away from it
• 1. Brain detects threat

  • Hypothalamus identifies the threat
  • Tells the sympathetic nervous system to act
• 2. Adrenaline released

  • ANS changes from parasympathetic to sympathetic nervous system (state of arousal)
  • Sympathetic nervous system releases adrenaline into the bloodstream
• 3. Fight or flight response

  • Adrenaline causes physiological changes to occur
  • Your heart rate increases, your pupils dilate, digestion stops and saliva production is stopped
  • These changes are designed to help us fight or flight
• 4. The threat has passed

  • ANS changes back to the parasympathetic nervous system
  • Heart rate slows down and other things continue
  • This is the rest and digest state