Adaptations(heart)

• What does the left ventricle of the heart have?

  thicker, more muscular walls than the right ventricle
• Why does the left ventricle of the heart have thicker, more muscular walls than the right ventricle?

  Because it needs to contract powerfully to pump blood all the way round the body

  (The right side only needs to get blood to the lungs- which are nearby)
• Do the ventricles or atria have thicker walls?

  ventricles
• what do the ventricles have?

  thicker walls than the atria
• Why do the ventricles have thicker walls than the atria?

  Because the ventricles have to push blood out of the heart

  WHEREAS the atria just need to push blood a short distance into the ventricles
• What are the AV valves?


  The atrioventricular valves
• What do the AV/ atrioventricular valves do?

  Link the atria to the ventricles and stop blood flowing back into the atria when the ventricles contract
• What are the SL valves?

  The semi-lunar valves
• What do the SL/ Semi-lunar valves do?

  link the ventricles to the pulmonary artery and aorta, and stop blood flowing back into the heart after the ventricles contract
• What do the CORDS do?

  Attach the atrioventricular valves to the ventricles to stop them being forced up into the atria when the ventricles contract
• What do the valves only do?


  only open one waY
• Whether the valves are open or closed depends on what?


  The relative pressure of the heart chambers
• When is a valve forced open?

  If there is higher pressure behind a valve, it is FORCED OPEN
• When is a valve forced shut?

  If pressure is higher IN FRONT of the valve it is FORCED SHUT
• Having valves means what?

  blood only flows in one direction through the heart
• when does valve open?

  when pressure above it is higher than pressure below it