BLOOD Blood cells Plasma 55 Platelets Thrombocytes 90

BLOOD Blood cells Plasma (55%) Platelets (Thrombocytes)

90% water, 10% chemicals, slightly alkaline p. H 7. 4. Transports chemicals and heat around the body What sort of chemicals? Important molecules such as glucose Waste products Mineral salts Hormones Plasma proteins Respiratory gases

They have no organelles including a nucleus to leave more room for haemoglobin. Ø ØLarge surface area due their bi-concave disc shape. This allows O 2 to diffuse quickly into and out of the cell ØThey have an elastic membrane which allows them to squeeze through small blood capillaries, then spring back into normal shape when they re-enter veins

These are larger than red blood cells but there are fewer of them in the blood. They are responsible for fighting disease. There are three different white blood cells for you to remember.

These white blood cells engulf pathogens and microorganisms and digest them (phagocytosis ). A non specific process which occurs whatever the infection. • They have an elongated nucleus and a flowing cytoplasm – this enables them to squeeze through gaps between cells to move to the site of infection in body tissues • Their cytoplasm contains many lysosomes to aid digestion Monocytes =Agranulocyte (non granular cytoplasm. Neutrophil = Granulocyte (granular cytoplasm)

ØAct against microorganisms, with some lymphocytes secreting antibodies (a range of glycoproteins) that between them immobilise and kill microorganisms and make them ready for phagocytes to engulf. ØLarge nucleus. ØThese white blood cells are specific. Each type of lymphocyte acts against one particular pathogen. ØThey provide long term immunity to future infections.