and deliver carbon dioxide to the lungs. It contains enormous amounts of protein called haemoglobin, which is responsible for its dark or bright red colour. They are also important in determining your blood type. (Ivy Rose, 2003-2013). [2] White Blood Cells: Leucocytes are the body’s defence army within the blood tissue and make up less than 1% of the blood. They are the only true cells in the blood and are not limited to the blood stream. There are many types of white blood cells, each one has a different structure and function and are part of the immune system. (Ivy Rose, 2003-2013). [3] Platelets: Thrombocytes these are cell fragments that help in blood clotting. At the site of an injury, platelets will stick to the exposed collagen and trap other blood cells in the form of a clot and stop blood from flowing and preventing excessive blood loss. The platelets contract and pull the injury back together, the blood will clot and aid in healing. (Ivy Rose, 2003-2013).[4] Blood Tissue Function Blood is mainly for transportation of dissolved gases and of metabolic waste. It also helps to maintain the body’s temperature. It removes toxins from the body, via the kidneys in the form of urine or sweat. (Pearson, 2014). [1] Blood Vessels Structure and Function Arteries: these carry blood from the heart under high pressure. They have thick outer walls and thick layers of muscle with elastic fibres. (Pearson, 2014). [2] Veins: these work under low pressure and have thin walls and thin layers of >