the heart and blood vessels

• what do the arteries do?


  1. carry oxygenated blood away from the heart and into the organs of the body.
  2. have thick walls containing muscle and elastic fibres
  3. blood is under pressure
• what do the veins do?


  1. carry deoxygenated blood away form the organs towards the heart.
  2. thinner walls than arteries and valves to prevent back flow of blood
• what do the capillaries do?


  1. capillaries form a huge network of tiny vessels linking the arteries and veins.
  2. narrow and thin walls
  3. substances can diffuse through the walls such as oxygen, carbon dioxide and glucose
• what makes up a human double circulatory system?


  1. one system carries blood from your heart to your lungs allowing oxygen and carbon dioxide to be exchanged with air in the lungs
  2. the other transport system carries blood from your heart to all other organs of your body and back again
• heart issues 


  1. damaged heart valves can be replaced using biological or mechanical heart valves
  2. artificial pacemakers are electrical devices that correct irregularities in heart rhythm by stimulating it to beat properly
  3. artificial hearts can be used to keep patients alive while they wait for a transplant or for their heart to rest as an aid to recovery
  4. stents can be used to keep narrow or blocked arteries open - cornary heart disease
  5. statins reduce cholesterol levels in the blood, reducing the risk of coronary heart disease
• how does the heart work?


  1. the ventricles contract and force blood out of the heart
  2. the right ventricle forces deoxygenated blood to the lungs in the pulmonary artery
  3. the left ventricle pumps oxygenated blood around the body in the aorta
• heart diagram