Adrenaline (Edexcel GCSE Biology: Combined Science)

Higher tier only

• Adrenaline is known as the fight or flight hormone as it is produced in situations where the body may be in danger
• It causes a range of different things to happen in the body, all designed to prepare it for movement (ie fight or flight). 
• These include: 
  • Increasing blood glucose concentration for increased respiration in muscle cells
  • Increasing heart rate and breathing rate so glucose and oxygen can be delivered to muscle cells, and carbon dioxide taken away, from muscles cells more quickly
  • Increased blood pressure
  • Diverting blood flow towards muscles and away from non-essential parts of the body such as the alimentary canal; again to ensure the reactants of respiration are as available as possible
  • Dilating pupils to allow as much light as possible to reach the retina so more information can be sent to the brain