Blood

• The heart


  • Pumps blood and oxygen around the body
• Red blood cells


  • Carry oxygen and glucose to cells
  • Remove waste products such as carbon dioxide and urea
• The role of the blood is to carry glucose, oxygen, amino acids and other useful substances around the body to the cells which need it. It then carries waste products such as carbon dioxide and urea away from cells to be excreted. The blood is also responsible for fighting infection.
• Components of the blood

  • Plasma
  • Platelets
  • Red blood cells
  • White blood cells
• Red blood cells


  • Made in the red bone marrow
  • Adapted to be small and flexible to fit through narrow vessels
  • Have a thin membrane so gases can easily diffuse through
  • Have a bi-concave shape to maximise surface area to absorb more oxygen
  • Contain haemoglobin, a protein molecule that binds to oxygen
• Oxyhaemoglobin


  • The oxygenated version of haemoglobin
• White blood cells


  • Help fight infection, viruses and bacteria
  • Made in bone marrow
  • Phagocytes engulf foreign particles, bacteria and dying cells to protect the body
  • Two types of lymphocytes: B cells produce antibodies, T cells destroy the body's own cells that have been taken over
• Platelets


  • Stop bleeding by forming clots
  • Made by precursor cells
• Haemophilia


  An inherited disorder where blood does not clot properly, leading to a lot of swelling in joints
• Plasma


  • A yellow liquid that resembles straw
  • Carries water, salts and enzymes
  • Transports nutrients and hormones around the body
• The heart is made out of muscle that squeezes the blood around the body.
• The heart


  1. Right side pumps blood to the lungs to pick up oxygen

  2. Left side pumps blood around the rest of the body
• Parts of the heart

  • Right atrium
  • Right ventricle
  • Left atrium
  • Left ventricle
  • Pulmonary artery
  • Aorta