the heart and circulation

• What is the circulatory system in fish like?

  • Single circulatory system
  • Deoxygenated blood is pumped to the gills
  • Blood collects oxygen and becomes oxygenated
  • Oxygenated blood goes to the organs
  • Blood returns to the heart
• What is a disadvantage of a single circulatory system in fish?

  Blood loses pressure as it passes through the gills, traveling slowly to the organs
• How does the double circulatory system in humans work?

  • Deoxygenated blood is pumped to the lungs
  • Blood collects oxygen in the lungs
  • Oxygenated blood returns to the heart
  • Heart pumps oxygenated blood to the organs
  • Blood transfers oxygen to body cells
• What is the benefit of the double circulatory system in humans?

  It allows blood to travel rapidly to body cells, delivering necessary oxygen
• What are the four chambers of the human heart?

  • Left atrium
  • Right atrium
  • Left ventricle
  • Right ventricle
• What separates the atria from the ventricles in the heart?

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

  Diagrams show the heart as if viewed from a person’s perspective
• What are the four main blood vessels associated with the heart?

  • Vena cava
  • Pulmonary artery
  • Pulmonary vein
  • Aorta
• What does the vena cava do?

  It brings oxygenated blood from the body to the heart
• What is the function of the pulmonary artery?

  It carries deoxygenated blood from the heart to the lungs
• What happens to blood in the lungs?

  It collects oxygen and becomes oxygenated
• What is the role of the pulmonary vein?

  It carries oxygenated blood from the lungs to the heart
• What does the aorta do?

  It pumps oxygenated blood from the heart to the body
• Describe the pattern of blood flow through the heart.

  1. Blood enters the left and right atria
  2. Atria contract, forcing blood into the ventricles
  3. Ventricles contract, forcing blood out of the heart
  4. Valves prevent backflow into the atria
• Why does the left ventricle have a thicker muscular wall than the right ventricle?

  It pumps blood around the entire body, requiring greater force
• What are coronary arteries?

  Arteries that branch out of the aorta and supply oxygen to the heart muscle
• What is the purpose of the coronary arteries?

  To supply oxygen to the muscle cells of the heart
• What is the natural resting heart rate controlled by?

  A group of cells found in the right atrium called the pacemaker
• What happens if the pacemaker stops working correctly?

  Doctors can implant an artificial pacemaker to correct irregularities
• What is an artificial pacemaker?

  A small electrical device that corrects irregularities in heart rate