Hematology is a branch of medicine that deals with blood, blood forming organs and diseases of the blood. The process of formation of blood cells is known as haemopoiesis. All blood cells are derived from a pluripotent stem cell. This stem cells has two important properties which are self-renewal following proliferation and differentiation into progenitor cells committed to a specific cell line. Differentiated cells includes red blood cells, white blood cells and platelets. Each differentiated cell produce has unique or specific role.
Red blood cells
Also known as erythrocytes. Red blood cells uses hemoglobin to transport oxygen and carbon dioxide between the lungs and the rest of the body.
White blood cells
White blood cells serves as the defense unit against foreign substance or molecules. It is further differentiated to granulocytes and agranulocytes. Granulocytes includes: Neutrophil, Basophil, and Eosinophil while agranulocytes are monocytes and lymphocytes.
Neutrophils phagocytize foreign materials or dead to damage cells particularly at sites of inflammation. Neutrophil also activate bactericidal mechanism and produce mediators of chemotaxis. The presence of neutrophil is commonly associated to bacterial infection.
It has the same function of neutrophil but are specific markers of parasitic infections. Eosinophils regulate immediate hypersensitivity reactions.
Basophil are sources of most histamine in the human body. It can be coated in Immunoglobulin E and releases histamine. Basophils mediate type-I hypersensitivity reactions. The presence of basophil in circulating blood serum is an indication of allergies reaction or hypersensitivity. Mast cells in tissues are similar to basophils in blood.
Monocytes are agranulocytes and become macrophages once in tissues. They are found throughout the body as part of the reticuloendothelial system and phagocytes pathogens, cellular debris and produces various cytokines. Monocytes processes and present antigen to lymphocytes as part of the adaptive immune response. Specialized mononuclear cells (dendritic cells) present antigen to T cells.
B-lymphocytes are plasma cells and are responsible for the production of immunoglobulin. They can also become memory cells.
Cytotoxic CD8 T-cell kill cells infected by intracellular microorganism meanwhile CD4 T helper cells produces cytokines to activate B cells or macrophages.
Natural killer (NK) cells
NK cells kills foreign cells or molecules by antibody-dependent cell mediated cytotoxicity.
Platelets are involved in hemostatic response to vascular injury by adhering to sub endothelial connective tissue.
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