Circulatory system

• Circulatory system


  • Transports food and oxygen around the body
  • Transports waste substances out of cells
• Components of blood

  • Red blood cells
  • White blood cells
  • Platelets
  • Plasma
• Red blood cells- Produced in the bone marrow.


  • Specialised to carry oxygen
  • No nucleus to increase space for oxygen
  • Biconcave disc shape to increase surface area
  • Contain haemoglobin
• White blood cells- Does has a nucleus & produced in bone marrow.


  • Fight infection and are part of the immune system
  • Can change shape to engulf pathogens by phagocytosis
  • Some produce antibodies and antitoxins
• Platelets- broken off from large cells in the bone marrow.


  • Cell fragments important for blood clotting
  • Activate at injury sites to form clots
• Plasma


  The liquid in blood that carries all the substances
• Blood Clotting


  A process that reduces bleeding when we are injured.
• Haemoglobin


  A protein that binds to oxygen in the lungs and releases it in body tissues.
• oxygen


  used for survival - to help organisms grow, reproduce and turn food into energy.
• Blood is made up of 45% of cells and 55% of plasma.
• Blood is a tissue and it's carried around the body in blood vessels.
• Blood's functions includes:


  Transporting substances

  Defence against pathogens

  Control of body temperature

  Maintaining pH of fluids.
• Plasma transports:

  red blood cells, white blood cells, platelets, nutrients, hormones, proteins, carbon dioxide, urea, glucose, amino acids, anti-bodies, anti-toxins