heart and blood vessels

• the heart

  is an organ that pumps blood around the body in a double circulatory system.
• where does the right ventricle pump to?

  The right ventricle pumps blood to the lungs where gas exchange takes place.
• where does the left ventricle pump to?


  The left ventricle pumps blood around the whole body.
• how is the heart rate controlled?

  The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker.
• what do arteries do?

  Carry blood away from the heart (except the pulmonary artery)
• what is the structure of an artery and how does it affect the function?

  Have thick muscular walls so they can contain blood under high pressure
• what do veins do?

  Carry blood to the heart (except pulmonary vein)
• what is the structure of a vein and how does it affect the function?

  Have thin walls so they can contain blood under low pressure and they have valves to prevent the blood flowing backwards
• what do capillaries do?

  connect arteries to veins
• what is the structure of a vein and how does it affect the function?

  cell thick which makes them effective for diffusion
• what is the structure of the alveoli and how does it affect the function?

  Alveoli have a large surface area and are one cell thick to allow fast gas exchange.
• what are alveoli surrounded by?

  a network of capillaries giving them a good suply of blood making it easier for gas exchange
• what is the blood made up of?

  plasma, red blood cells, white blood cells and platelets.
• what do red blood cells do?


  carry oxygen
• what does plasma do?

  Contains dissolved substances and transports them around the body e.g. glucose and carbon dioxide.
• what do platelets do?

  they help clot the blood and form scabs
• what do white blood cells do?

  Help to protect the body against infection
• what does haemaglobin do?

  absorbs oxygen (this is why red blood cells contain a lot of haemaglobin)