They circulate in the blood of mammals and are involved in hemostasis, leading to the formation of blood clots. Platelets are a natural source of growth factors. The average lifespan of a platelet is normally just 5 to 9 days. Platelets, or thrombocytes, are very small, irregularly shaped clear cell fragments, 2–3 µm in diameter, which derive from fragmentation of megakaryocytes. Many hematological cancers are based on the inappropriate production of white blood cells. The number of white blood cells in circulation is commonly increased in the incidence of infection.

There are individual terms for the lack or overabundance of specific types of white blood cells. The condition of having too few white blood cells is leukopenia, while having too many is leukocytosis. Agranulocytes include lymphocytes and monocytes. Granulocytes include basophils, eosinophils, neutrophils, and mast cells. White blood cells are divided into granulocytes and agranulocytes, distinguished by the presence or absence of granules in the cytoplasm. WBCs constitute approximately 1% of the blood volume. There are a variety of types of white bloods cells that serve specific roles in the human immune system. Leukocytes are found throughout the body, including the blood and lymphatic system. They are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells. White blood cells or leukocytes, are cells of the immune system involved in defending the body against both infectious disease and foreign materials. From left to right: erythrocyte, thrombocyte, leukocyte. Normal values of ESR are:Īrtificially colored electron micrograph of blood cells. The condition of having too few red blood cells is known as anemia, while having too many is polycythemia.Įrythrocyte sedimentation rate (ESR) is the rate at which RBCs sink to the bottom (when placed in a vertical column after adding an anticoagulant). Mature red blood cells are unique among cells in the human body in that they lack a nucleus (although erythroblasts do have a nucleus). After they have completed their lifespan, they are removed from the bloodstream by the spleen. RBCs have a lifespan of approximately 100-120 days. The normal RBCs count is 4.5 to 5 millions per cu.mm. In adults, about 2.4 million RBCs are produced each second. RBCs are formed in the red bone marrow from hematopoietic stem cells in a process known as erythropoiesis. Red blood cells are much smaller than most other human cells. Red blood cells are circular, biconcave, disk-shaped and deformable to allow them to squeeze through narrow capillaries. Red blood cells are the most abundant cell in the blood, accounting for about 40-45% of its volume. Hemoglobin is an iron-containing protein that gives red blood cells their color and facilitates transportation of oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs to be exhaled. Red blood cells or erythrocytes, primarily carry oxygen and collect carbon dioxide through the use of hemoglobin. The darker red blood syringes have deoxygenated blood, whereas the brighter red have oxygenated blood.

Misshapen blood cells