Components of Blood (Cambridge (CIE) IGCSE Combined Science: Biology): Revision Note

Components of blood

• Blood consists of red blood cells, white blood cells, platelets and plasma

Components of the blood table

Identifying red & white blood cells

• Red and white blood cells can be identified in photomicrographs and diagrams by:

  • red blood cells have a concave disc shape with no nucleus

  • white blood cells are usually round in shape with a nucleus

Components of blood: function

• Plasma is important for the transport of:

  • the blood cells (red blood cells, white blood cells and platelets)

  • nutrients

  • urea

  • ions

  • hormones

  • carbon dioxide

• Red blood cells transport oxygen around the body from the lungs to cells around the body; oxygen is required for aerobic respiration

  • Red blood cells carry oxygen in the form of oxyhaemoglobin

• White blood cells defend the body against infection by pathogens by carrying out phagocytosis and antibody production

• Platelets are involved in blood clotting