The Blood and Lymph System

Blood and Lymph System Definition The blood and lymph are the cell-bearing fluids that nourish and protect the body. Physician specialists who treat conditions of the blood and lymph are hematologists. Functions of the Blood and Lymph The blood and the lymph are the body’s vital fluids, sharing responsibility for nourishment, cleansing, immune response, and […]

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Albumin – Definition and Levels – Normal, Low, High

Definition of Albumin Albumin is the most abundant protein in plasma – transports various molecules through the blood and helps sustain the blood’s oncotic pressure, keeping fluid from seeping into the tissues. Albumin is among the numerous plasma proteins the liver produces and is also available as a blood product for transfusion. Blood banks obtain it by separating it, using […]

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Coagulation Cascade – Blood Process

Definition of Coagulation Cascade Coagulation – the process, also called the coagulation cascade, through which the blood forms clots. The cells responsible for forming clots are platelets, which interact with each other, collagen, proteins, and other substances in the blood. Specialized proteins in the blood, called clotting factors, activate in cascades, with one activation leading to another in […]

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Erythropoietin (EPO) – Definition, Side Effects

Definition of Erythropoietin (EPO) A hormone the kidneys produce that stimulates the bone marrow to increase red blood cell production. Erythropoietin is a protein structure called a cytokine. Specialized cells in the renal cortex, called peritubular fibroblasts, respond to the amount of oxygen in the blood as it passes through the kidney. When the oxygen […]

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Granulocyte – Basophils, Eosinophils, Neutrophils

Definition of Granulocytes Granulocyte – a type of leukocyte (white blood cell) so named because its cytoplasm contains granules. The granules, called lysosomes in neutrophils, contain enzymes that digest proteins and carbohydrates, the basic components of cellular structures. Granulocytes are primarily phagocytic; their responsibility is to consume pathogens that lymphocytes and other leukocytes neutralize as part of the body’s immune response. […]

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Hematopoiesis Definition – Pluripotency, Differentiation, and Proliferation

Definition of Hematopoiesis The process through which the body generates new blood cells. In the adult, the red bone marrow and the lymph tissues (primarily the lymph nodes and the spleen) manufacture the blood cells the body needs, with extramedullary resources for erythrocyte production available as reserves from the liver, spleen (erythrocytes), and yellow bone marrow. Researchers […]

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Hemolysis – Definition and Conditions

Definition of Hemolysis The destruction and disassembly of erythrocytes (red blood cells). Erythrocytes live in the blood for about 120 days after their release from the bone marrow. At the end of this time they either die or the spleen culls them from circulation. The spleen partially dismantles the erythrocytes, reducing toxic heme into bilirubin […]

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Platelet Aggregation – Definition and Function

Definition of Platelet Aggregation The process through which platelets respond to chemical signals in the blood, allowing them to adhere to each other and to collagen fibers in the blood to form the hemostatic plug that will become a blood clot at the conclusion of the coagulation cascade. The formation of collagen and the conversion […]

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Polycythemia Vera – Definition, Symptoms and Treatment

Definition of Polycythemia Vera A myeloproliferative condition of the blood in which the red bone marrow produces an excessive volume of erythrocytes (red blood cells), platelets, and neutrophils that results in increased cell volume and decreased fluid volume (plasma) in the blood. This myeloproliferation (overproduction by the bone marrow) thickens the blood (hyperviscosity), making it […]

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Reticulocyte – Definition and Count

Definition of Reticulocyte An erythrocyte (red blood cell) that enters the blood’s circulation from the bone marrow just before it has reached maturity. Reticulocytes are somewhat larger than erythrocytes and normally make up about 1 percent of the erythrocytes in circulation. A reticulocyte matures into an erythrocyte after being in circulation for about a day. Reticulocytes are still […]

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