Blood is a specialized body fluid that delivers necessary substances to the tissues and transports waste products away from the tissues. The main components of blood are plasma, red blood cells, white blood cells, and platelets. Blood is produced through hematopoiesis, a process where stem cells in the bone marrow mature into the various blood cell types.

Red Blood Cells

Red blood cells, also called erythrocytes, are the most abundant cell type found in blood. Their main function is to transport oxygen from the lungs to tissues and carbon dioxide from tissues back to the lungs. Red blood cells lack a cell nucleus and other organelles, which allows maximum space for the oxygen-carrying protein Hematology. Anemia is a condition where the number of red blood cells or their oxygen-carrying capacity is reduced. This can result from blood loss, disturbances in red blood cell production or increased red blood cell destruction.

White Blood Cells

White blood cells, or leukocytes, are essential components of the immune system. The main types of white blood cells are granulocytes like neutrophils, eosinophils and basophils, and agranulocytes like lymphocytes and monocytes. Neutrophils are the most abundant white blood cell and act as the body’s first line of defense against invading microbes. Lymphocytes include T cells and B cells that play major roles in adaptive immunity through cell-mediated and humoral immunity respectively. Monocytes differentiate into macrophages that engulf and digest pathogens and cellular debris. Leukemia involves the abnormal proliferation of white blood cells in the bone marrow and blood.