The components of the blood and their jobs

What is blood made up of? • • • Red blood cells White blood cells Platelets Plasma Breakdown products of digestion, such as glucose, fatty acids and amino acids Dissolved mineral salts Carbon dioxide Urea hormones

What is plasma? • Plasma is the liquid part of the blood which carries everything else. • Plasma is a straw-yellow coloured liquid • If everything in plasma was removed, plasma would look like this

What do the different parts of blood look like under a microscope? Red blood cells White blood cells

What is the job of red blood cells? • They have a round, flat disc shape for a large surface area • They do not have a nucleus • They contain haemoglobin which combines with oxygen in areas of high concentration to form oxyhaemoglobin • Oxygen + haemoglobin oxyhaemoglobin • Red blood cells carry oxygen to the cells of the body for use in respiration

What do white blood cells do? • White blood cells help the body to fight invading bacteria • White blood cells will engulf and ingest invading bacteria

Other important jobs of the white blood cells: • They produce antibodies which can recognise and fight bacteria • They produce antitoxins which neutralise the toxins (poisons) that bacteria produce, which make us feel ill

What do platelets do? • Platelets are fragments of cells • The job of platelets is to help blood clot and form a scab • The platelets are involved in the formation of fibrin, which is needed for clotting blood • This is useful for stopping bleeding, and for preventing germs from entering the body through the cut

Summary of the composition of blood

Questions on the blood • • • What part of blood carries oxygen to cells? Why are red blood cells flat disc-shaped? What is the job of platelets? What do white blood cells do? Describe how a white blood cell carries out its job. • What is the straw-coloured liquid which carries all the other parts of blood called?

More questions on blood A • Name cell A • Name cell B B

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