Coordinated responses

• Fight or flight response:

  • hypothalamus activates the sympathetic nervous system
  • hypothalamus stimulates the pituitary gland to secrete ACTH
  • the sympathetic nervous system sends out impulses to glands and smooth muscles and tells the adrenal medulla to release adrenaline and noradrenaline
  • ACTH travels in the blood to the adrenal cortex where it activates the release of many other hormones
• Adrenaline:

  • binds with receptors on the surface of a liver cell
  • adenylyl cyclase is activated
  • adenylyl cyclase triggers the conversion of ATP into cAMP (the secondary messenger)
  • cAMP activates protein kinases which activate other enzymes (e.g. glycogen into glucose)