the heart

• Circulatory system


  An example of an organ system whose role is to transport oxygen and nutrients to the body's tissues
• Circulatory system


  • Relies on 3 main things: blood, blood vessels, heart
• Blood flow through the circulatory system

  1. Blood flows from heart to lungs (gains oxygen)

  2. Blood flows from lungs back to heart

  3. Blood flows from heart to rest of body (gives up oxygen)

  4. Blood flows from body back to heart
• Heart


  Consists of 4 chambers with thick muscular walls, and veins/arteries
• When looking at a diagram of the heart, the left side is on the right and the right side is on the left
• Atria


  Top chambers of the heart
• Ventricles


  Bottom chambers of the heart
• Valves


  Prevent blood from flowing backwards between chambers and vessels
• Blood flow through the heart

  1. Blood flows into right atrium and left atrium

  2. Atria contract to push blood into ventricles

  3. Ventricles contract to push blood out to lungs and body

  4. Atria refill with new blood
• Pacemaker cells


  Produce electrical impulses to regulate the heart's contractions
• Artificial pacemaker


  Small device implanted 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 don't always carry oxygenated blood, and veins don't always carry deoxygenated blood
• Coronary arteries


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