Cardiac cycle

• Where is the heart located in the body?

  In the chest cavity between the lungs
• What is the name of the heart muscle?

  Myocardium
• What is the blood vessel that delivers blood from the heart to the lungs?

  Pulmonary artery
• What is the benefit of double circulation?

  Delivers blood to tissues faster
• What are the three stages of the cardiac cycle?

  Atrial systole, ventricular systole, diastole
• What does the 'lub' noise heard with a stethoscope indicate?

  AV valves closing
• What does the 'dub' noise heard with a stethoscope indicate?

  Semilunar valves closing
• What happens during atrial systole?

  Atria contract, ventricles are relaxed
• What occurs during ventricular systole?

  Ventricles contract, atria are relaxed
• What prevents backflow of blood into the ventricles during systole?

  AV valves are closed
• What happens during diastole?

  Ventricles relax and atria fill with blood
• What prevents backflow of blood from the arteries during diastole?

  Semi-lunar valves are closed
• What is the equation for cardiac output?

  Cardiac Output = Stroke Volume x Heart Rate
• How does exercise affect stroke volume and heart rate?

  Both stroke volume and heart rate increase
• How does fitness level affect resting heart rate and stroke volume?

  A fit person has a lower resting rate
• Why does a fit person have a higher stroke volume?

  They have strong cardiac muscle
• What is the relationship between heart rate and the need for the heart to beat often at rest?

  The heart doesn't need to beat as often at rest
• What prevents backflow of blood into the ventricles during atrial systole?

  Semi-lunar valves are closed
• What happens to the pressure in the ventricles during ventricular systole?

  Pressure increases as blood is forced out
• What is the role of the AV valves during the cardiac cycle?

  Prevent backflow of blood into atria
• What is the role of the semi-lunar valves during the cardiac cycle?

  Prevent backflow of blood into ventricles
• How do pressure changes affect the opening and closing of heart valves?

  Pressure gradients determine valve states
• What are the stages of the cardiac cycle?

  1. Atrial systole

  • Atria contract, ventricles relax
  • Blood moves from atria to ventricles

  1. Ventricular systole

  • Ventricles contract, atria relax
  • Blood is forced into arteries

  1. Diastole

  • Ventricles and atria relax
  • Atria fill with blood from veins
• What are the pressure changes during the cardiac cycle?

  • Atrial systole: Pressure in atria increases
  • Ventricular systole: Pressure in ventricles increases
  • Diastole: Pressure in ventricles decreases
• What is the significance of the cardiac cycle in relation to heart function?

  • Ensures efficient blood flow
  • Maintains oxygen delivery to tissues
  • Regulates heart rate and pressure