Structure and function of red and white blood cells and platelets

Red cells have a major function in transport of oxygen, and minor functions in regulation of local blood flow and transport of carbon dioxide. Neutrophils and monocytes are phagocytic cells that are part of the innate and also the adaptive immune response. Eosinophils have their major function in protecting against multicellular parasites, and basophils participate in this process. Dendritic cells participate in regulation of T cell function. B cells are part of the adaptive immune response, specifically differentiating to plasma cells, which are responsible for humoral immunity. Some T cell subsets and natural killer (NK) cells mediate cellular immunity, both innate and adaptive, while other T cell subsets suppress the activity of B cells, helper T cells and cytotoxic T cells. NK cells and cytotoxic T cells are important in defence against tumours. Platelets function in primary haemostasis and, on activation, provide phospholipid that is essential for the activation of coagulation factors.