The Heart

• How a single circulatory system works (in fish)

  • Fish have a single circulatory system 
  • Deoxygenated blood is pumped from the heart to the gills , where the deoxygenated blood collects oxygen and becomes oxygenated 
  • The oxygenated blood passes straight from the gills to the organs , where the oxygen diffuses out of the oxygenated blood and into the body cells 
  • The blood, which is now deoxygenated , returns to the heart

  
• What is the problem with a single circulatory system? (Like the one in fish)

  • The problem with a single circulatory system is that the blood loses a lot of pressure as it passes through the gills before reaching the organs 
  • This means that the blood travels to the organs relatively slowly , so it cannot deliver a great deal of oxygen
• How does a double circulatory system work (in humans)

  • Deoxygenated blood is pumped to the lungs, where it collects oxygen and becomes oxygenated 
  • Te oxygenated blood returns to the heart 
  • The heart pumps the oxygenated blood to the organs (or rest of the body), where the oxygenated blood transfers it’s oxygen to the body cells to become deoxygenated  
  • The deoxygenated blood now returns back to the heart

  
• What are the benefits of a double circulatory system (like the one in humans)

  The benefit of the double circulatory system is that because the blood passes through the heart twice, it can travel rapidly to the body cells delivering the oxygen that the cell needs
• What is the heart

  • The heart is an organ consisting mainly of muscle tissue 
  • It’s job is to pump blood around the body

  
• What are the 4 chambers of the heart?

  • Left atrium 
  • Right atrium 
  • Left ventricle 
  • Right ventricle 
  • The atria are separated from the ventricles by valves

  
• What are the 4 main blood vessels that enter and leave the heart?

  • Aorta 
  • Pulmonary artery 
  • Vena cava 
  • Pulmonary vein

  
• What is the function of the right atrium

  The right atrium pumps deoxygenated blood to the right ventricle 

  
• What is the function of the right ventricle

  The right ventricle pumps deoxygenated blood to the lungs (where gas exchange takes place)

  
• What is the function of left atrium

  The left atrium pumps oxygenated blood to the left ventricle

  
• What is the function of the left ventricle

  The left ventricle pumps oxygenated blood to the rest of the body

  
• What is the function of the vena cava

  The vena cava takes in deoxygenated blood from the body (and returns it to the right atrium)

  
• What is the function of the pulmonary artery?

  The pulmonary artery transports deoxygenated blood from the heart to the lungs

  
• What is the function of the pulmonary vein?

  The pulmonary vein transports oxygenated blood from the lungs to the heart

  
• What is the function of the aorta?

  The aorta transports oxygenated blood from the heart to the body (under high pressure, away from the left ventricle)

  
• Describe the pattern of blood flow through the heart

  • Blood enters the heart from the atria (left and right atrium) 
  • They then contract and force blood into the ventricles 
  • They then contract and force blood out of the heart

  
• Describe the pattern of blood flow through the heart

  • Blood enters the heart from the atria (left and right atrium) 
  • They then contract and force blood into the ventricles 
  • They then contract and force blood out of the heart 
  • The valves in the heart stop the blood from flowing backwards into the atria when the ventricles contract

  
• Why does the left side of the heart have a thicker muscular wall

  • The left side of the heart has a thicker muscular wall than the right side of the heart 
  • This is because the left ventricle pumps blood around the entire body , so it needs to provide a greater force 
  • The right ventricle only pumps blood to the lungs

  
• What is the role of the coronary arteries

  • The coronary arteries branch out of the aorta and they spread out into the heart muscle 
  • The purpose of the coronary arteries is to provide oxygen to the muscle cells of the heart 
  • The oxygen is used in respiration to provide the energy for contraction

  
• What is the pacemaker

  The pacemaker is a group of cells found in the right atrium that control the natural resting heart rate

  
• What is an artificial pacemaker

  • Sometimes the pacemaker stops working correctly 
  • In this case doctors can implant an artificial pacemaker 
  • An artificial pacemaker is a small electrical device that is used to correct irregularities in the heart rate