Adrenaline

• Adrenaline action

  • when it binds to its specific receptor, it activates an enzyme called ADENYLYL CYCLASE
  • this catalyses the conversion of ATP -> cAMP
  • cAMP activates protein kinase A enzymes
  • they initiate the process of glycogenolysis (an enzyme cascade)
• Adrenal glands

  • secrete adrenaline
  • situated just above the kidneys
  • outer part - adrenal cortex
  • inner part - adrenal medulla
• Adrenal cortex


  • secretes steroid hormones
  • cortisol - regulates metabolism of fats, proteins and glucose for energy
  • aldosterone - regulates salt and water levels in the blood, effecting blood volume and pressure (acts in the kidneys)
• Adrenal medulla


  • secretes adrenaline
  • secretes noradrenaline
• Stress responses in animals, initiated by adrenaline secretion

  • short term responses
  • increased breathing and heart rate
  • glycogen breaks down into glucose
  • some blood vessels are constricted, more blood to brain and muscles