B2

• Circulatory system


  An example of an organ system that transports oxygen and nutrients to the body's tissues
• Circulatory system


  • Relies on blood, blood vessels, and the heart
• The circulatory system can be thought of as a double circulatory system with two distinct loops</b>
• Path of blood through the heart

  1. Flows into right atrium and left atrium

  2. Atria contract to push blood into ventricles

  3. Ventricles contract to push blood into pulmonary artery and aorta

  4. Atria refill with new blood

  5. Cycle repeats around 70 times per minute
• Pacemaker cells


  Group of cells in the right atrium that produce electrical impulses to regulate the heart's contractions
• Artificial pacemaker


  Small device implanted under the skin above the heart to regulate the heart's contractions
• Artery


  Any vessel that carries blood away from the heart
• Vein


  Any vessel that carries blood to the heart
• Arteries do not always carry oxygenated blood, and veins do not always carry deoxygenated blood
• Coronary arteries


  • Small arteries that branch off the aorta to supply the heart muscle with oxygenated blood