Intrinsic control

• Intrinsic control - During exercise


  1. Increased venous return = increased ventricle stretch = increases force and speed of contractions = increased stroke volume

  2. Higher body temperature = faster nerve transmission so SA node fires quicker
• Intrinsic control - During recovery


  1. Decreased venous return = decreased ventricle stretch = decreases force and speed of contractions

  2. Lower body temperature = slower nerve transmission so SA node fires slower
• Venous return


  1. Increased VR = increased ventricle stretch

  2. Increases force and speed of contractions

  3. Increased stroke volume

  4. Also directly stimulates SA node to↑ HR
• Body temperature


  1. Higher body temperature = faster nerve transmission so SA node fires quicker

  2. Higher body temp = thinner blood

  3. Thinner blood travels faster = faster HR
• Venous return


  1. Decreased VR = decreased ventricle stretch

  2. Decreases force and speed of contractions