Biology

• What is the role of the circulatory system?

  To transport oxygen and nutrients to the body's tissues
• What are the three main components of the circulatory system?

  • Blood: carries oxygen and nutrients
  • Blood vessels: hold the blood
  • Heart: pumps the blood
• How can the circulatory system be described in terms of its structure?

  It can be thought of as a double circulatory system with two distinct loops
• What happens in the first loop of the double circulatory system?

  It carries deoxygenated blood from the heart to the lungs to gain oxygen
• What occurs in the second loop of the double circulatory system?

  It carries oxygenated blood to the rest of the body and returns deoxygenated blood to the heart
• What are the main structural features of the heart?

  • Four chambers: two atria and two ventricles
  • Thick muscular walls
  • Valves to prevent backflow of blood
• What are the top chambers of the heart called?

  Atria
• What is the individual chamber of the atria called?

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

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

  • Prevent backflow of blood
  • Ensure blood flows in the right direction
• Describe the path blood takes as it passes through the heart.

  1. Blood enters via the vena cava (deoxygenated) and pulmonary vein (oxygenated)

  2. Flows into the right atrium and left atrium

  3. Atria contract, pushing blood into the ventricles

  4. Ventricles contract, pushing blood into the pulmonary artery and aorta

  5. Cycle repeats
• How many times does the heart cycle in a minute?

  About 70 times
• How many times does the heart cycle in a day?

  Over 100,000 times
• What is the role of pacemaker cells in the heart?

  • They produce electrical impulses
  • Cause the heart muscles to contract
  • Help maintain a steady heartbeat
• What is an artificial pacemaker?


  A device implanted to regulate heart contractions when natural pacemaker cells fail
• What is the difference between arteries and veins?

  • Arteries: carry blood away from the heart
  • Veins: carry blood to the heart
  • Not always related to oxygenation (e.g., pulmonary artery carries deoxygenated blood)
• What do coronary arteries do?

  They supply oxygenated blood to the heart muscle
• Why are coronary arteries important?

  • They encircle the heart
  • Ensure the heart muscle receives oxygen and nutrients
• What is the main function of the heart?

  To pump blood throughout the body