blood cells (names, general appearance, role in maintaining health). tissue; you DO NOT need to know the names of all the immature stages. THIS LIST IS UNDER DEVELOPMENT AND MAY EXPAND Blood: a connective tissue containing liquid matrix (plasma) and formed elements including blood cells. Plasma: the liquid matrix of blood or lymph. Formed elements: cells or cell fragments present in blood or lymph. Red blood cells (erythrocytes): round red blood cells packed with oxygen-carrying hemoglobin, and lacking a nucleus when mature. White blood cells (leucocytes): pale-colored blood cells (of several kinds) without hemoglobin. Granular leucocytes (granulocytes): leucocytes containing granules distinguished by their staining properties. Neutrophils: the most common leucocytes, phagocytic cells with a multi-lobed nucleus and granules staining with neutral dyes. Basophils: leucocytes with granules that stain with basic dyes. Eosinophils: leucocytes that stain with acidic dyes such as eosin. Lymphocytes: non-granular leucocytes essential in immune functions. Monocytes: large non-granular leucocytes that become tissue macrophage cells (phagocytic). Megakaryocytes: large cell from which platelets are derived. Platelets: cellular fragments essential in blood clotting. Clotting: deposition of insoluble fibrin, a process that turns blood into solid connective tissue. Serum: the watery fluid remaining after blood clots; blood serum minus its proteins. Lymphoid tissue: tissue (in spleen, thymus, etc.) in which nongranular leucocytes mature. Myeloid tissue: tissue (in bone marrow) in which granular leucocytes mature. Hematopoiesis: the process of blood cell formation in myeloid and lymphoid tissues. Erythroblast: an immature erythrocyte before its nucleus is extruded. Antigen: any molecule provoking an immune response. Antibody: a soluble protein molecule that binds to a specific antigen. Anemia: reduction in the oxygen-carrying capacity of blood (for any of several reasons, including the following). Sickle-cell anemia: anemia caused by a gene mutation in hemoglobin that results in deformed erythrocytes. (The allele, common in many African populations, confers protection against malaria.) Thalassemia: anemia (often mild) caused by a gene mutation that results in a shortened hemoglobin chain. (Thalassemia alleles, more common in Mediterranean populations, also confer protection against malaria.) Malaria: blood infection caused by a parasitic protist (Plasmodium falciparum and related species), causing anemia, fever, weakness, and frequently death. Hemophilia: lack of clotting ability in the blood. Polycythemia vera: very rare cancer in which red blood cells are excessively produced. Leukemia: any cancer of leucocytes (several kinds). |