The Cardiac cycle

• What are the three stages of the cardiac cycle in order?

  Atrial systole,

  ventricular systole,

  diastole.
• What happens in Atrial Systole?

  • The ventricles relax, and the atria contract.
  • This increases the atrial pressure.
  • Blood flows into the ventricles.
• What happens in Ventricular Systole?

  • The ventricles contract, and the atria relax.
  • The ventricular pressure increases.
  • The semi-lunar valves open, and the atrioventricular valves close.
  • Blood flows into the Aorta.
• What happens in Diastole?

  • The ventricles and atria relax.
  • The semi-lunar valves close.
  • Blood flows passively into the atria.
• Label the diagram

  A) Atrial Systole

  B) Ventricular Systole

  C) Diastole