The Heart and Circulation

• What type of circulatory system do fish have?

  Single circulatory system
• Where does deoxygenated blood go in fish?

  To the gills for oxygenation
• What happens to blood after it collects oxygen in fish?

  It passes to the organs
• What is a disadvantage of a single circulatory system?

  Blood loses pressure before reaching organs
• What type of circulatory system do humans have?

  Double circulatory system
• What is the benefit of a double circulatory system?

  Blood can travel rapidly to body cells
• How many chambers does the human heart have?

  Four chambers
• What are the names of the upper chambers of the heart?

  Left atrium and right atrium
• What are the names of the lower chambers of the heart?

  Left ventricle and right ventricle
• What separates the atria from the ventricles?

  Valves
• Why does the heart appear back to front in diagrams?

  It shows the view as if looking at a person
• What blood vessel brings oxygenated blood from the body to the heart?

  Vena cava
• What blood vessel carries blood from the heart to the lungs?

  Pulmonary artery
• What blood vessel carries oxygenated blood from the lungs to the heart?

  Pulmonary vein
• What blood vessel carries blood from the heart to the body?

  Aorta
• What happens when blood enters the atria?

  Atria contract and force blood into ventricles
• What prevents blood from flowing backwards into the atria?

  Valves in the heart
• Why does the left ventricle have a thicker muscular wall than the right ventricle?

  It pumps blood around the entire body
• What do coronary arteries supply to the heart muscle?

  Oxygen
• What is the purpose of oxygen in heart muscle cells?

  Used in respiration for energy
• What controls the natural resting heart rate?

  A group of cells in the right atrium
• What is an artificial pacemaker?

  A device that corrects heart rate irregularities
• What is the pattern of blood flow through the heart?

  1. Blood enters the left and right atria
  2. Atria contract, forcing blood into ventricles
  3. Ventricles contract, pumping blood out of the heart
  4. Valves prevent backflow into atria
• What are the differences between the circulatory systems of fish and humans?

  • Fish: Single circulatory system
  • Blood goes from heart to gills, then to organs
  • Blood loses pressure, travels slowly
  • Humans: Double circulatory system
  • Blood goes from heart to lungs, then to organs
  • Blood maintains pressure, travels rapidly