Biology - GCSE

• Circulatory system


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


  • Relies on 3 main things: blood, blood vessels, heart
• Blood


  Carries oxygen and nutrients
• Blood vessels


  Hold the blood
• Heart


  Pumps the blood to keep it moving through the vessels
• Circulatory system


  Deoxygenated blood from heart to lungs, oxygenated blood from lungs to rest of body
• Heart


  • Consists of 4 chambers with thick muscular walls, veins and arteries coming in and out
• 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, ensure blood flows in the right direction
• Blood flow through the heart

  Flows into right atrium and left atrium, then into ventricles, then out to lungs and body
• Pacemaker cells


  Produce electrical impulses to make the heart contract regularly
• Artificial pacemaker


  Small device implanted under the skin above the heart to regulate heart 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, veins don't always carry deoxygenated blood
• Coronary arteries


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