- Red blood cell – 45%, contains haemoglobin to transport oxygen
- White blood cell (lymphocytes) – <1% – produces antibodies to destroy pathogens, memory lymphocytes gain immunity
- White blood cell (phagocytosis) – <1% – engulfs and digests microorganisms
- Platelets – <1% – cell fragments which helps to clot the blood
- Plasma – 55% – Yellow liquid which transports dissolved food molecules, carbon dioxide and urea and blood cells. Mainly water.