The Heart

• What type of system is the circulatory system?

  An organ system
• What is the main role of the circulatory system?

  To transport oxygen and nutrients
• How many main components does the circulatory system rely on?

  Three
• Which component of the circulatory system carries oxygen and nutrients?

  Blood
• Which component of the circulatory system holds the blood?

  Blood vessels
• Which component of the circulatory system pumps the blood?

  Heart
• Why is the circulatory system referred to as a double circulatory system?

  Because there are two distinct loops
• What does one loop of the circulatory system carry?

  Deoxygenated blood to the lungs
• What happens to blood in the lungs?

  It gains oxygen
• What does the other loop of the circulatory system carry?

  Oxygenated blood to the body
• What happens to blood in the body's tissues?

  It gives up its oxygen
• How many chambers does the heart consist of?

  Four
• What surrounds the chambers of the heart?

  Thick muscular walls
• In diagrams, how is the heart typically oriented?

  As if viewing another person's front
• In a heart diagram, which side represents the left side of the heart?

  The right side
• What are the top chambers of the heart called?

  Atria
• What is a single top chamber of the heart called?

  Atrium
• What are the bottom chambers of the heart called?

  Ventricles
• What structures are found between the chambers and vessels of the heart?

  Valves
• What is the function of the valves in the heart?

  To prevent backflow of blood
• How does blood initially enter the heart?

  Via the vena cava and pulmonary vein
• Which chamber does blood from the vena cava flow into?

  The right atrium
• Which chamber does blood from the pulmonary vein flow into?

  The left atrium
• What is the oxygenation status of blood from the pulmonary vein?

  Oxygenated
• What is the oxygenation status of blood from the vena cava?

  Deoxygenated
• What happens when the atria contract?

  They push blood into the ventricles
• What happens when the ventricles contract?

  They push blood into the arteries
• Which artery does blood from the ventricles flow into to reach the lungs?

  Pulmonary artery
• Which artery does blood from the ventricles flow into to reach the rest of the body?

  Aorta
• What happens to the atria while the ventricles are contracting?

  They refill with blood
• Approximately how many times per minute does the heart cycle repeat?

  70
• Approximately how many times per day does the heart cycle repeat?

  100,000
• Where are the pacemaker cells located?

  In the right atrium
• What do pacemaker cells produce?

  Small electrical impulses
• What is the function of the electrical impulses produced by pacemaker cells?

  To cause the heart to contract
• What device can doctors use to fix pacemaker cells that don't work properly?

  An artificial pacemaker
• Where is an artificial pacemaker placed?

  Under the skin above the heart
• How does an artificial pacemaker work?

  By sending electrical signals to the heart
• What defines a vessel as an artery?

  It carries blood away from the heart
• What defines a vessel as a vein?

  It carries blood to the heart