Plasma – Definition and Information

Definition of Plasma Plasma – The liquid portion of the blood. Plasma is about 90 percent water and makes up 55 percent of the total blood volume. It contains numerous substances dissolved in it including electrolytes, hormones, enzymes, antibodies, glucose, and clotting factors (specialized proteins). It also carries the blood cells in suspension. Plasma is available for transfusion as […]

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Platelet – Definition, Function, Normal Platelet Count

Definition of Platelet, Function The cellular structure indispensable for coagulation (clotting), also called a thrombocyte. Platelets, which are actually cell fragments rather than intact cells, separate from parent cells in the bone marrow called megakaryocytes, the largest cells in the bone marrow. When platelets emerge into the circulation they become the smallest cell particles in […]

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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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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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Blood – Plasma and Cells

Definition of Blood Blood – the cell-filled fluid that carries vital chemicals and nutrients via the cardiovascular system to tissues and cells throughout the body. The heart pumps the blood, sending it under pressure through a closed network of arteries and veins. The blood provides volume within the cardiovascular system, establishing both blood pressure and osmotic pressure (the […]

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Blood Stem Cells – Definition and Information

Definition of Blood Stem Cells The parent cells from which all blood cells arise. Blood stem cells are pluripotent or undifferentiated, which means they have the ability to become any of the three types of blood cells (erythrocytes, leukocytes, or platelets). Intricate biochemical interactions determine how the blood stem cell will differentiate (become a specific […]

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Blood Type – A, B, 0, AB, ABO – Percentages Among Americans

Definition of Blood Type Blood Type – the pattern of specialized proteins, called agglutinogens or antigens, present on the surface of the red blood cells (erythrocytes). The presence of antigens on the erythrocytes causes the immune system to create oppositional antibodies, which will attack cells bearing the opposing antigens. Antigens and corresponding antibodies begin to develop shortly following birth. […]

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Erythrocyte – Definition and Information

Definition of Erythrocyte A red blood cell (RBC). The primary function of erythrocytes is to carry oxygen from the lungs to the cells of tissues throughout the body and return carbon dioxide, a metabolic waste, to the lungs for removal from the body. Erythrocytes contain iron and hemoglobin, a pigmented protein that gives them their […]

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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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Hemoglobin – Definition, Levels, Information

Definition of Hemoglobin Hemoglobin is a combined protein within erythrocytes (red blood cells) that is crucial to the oxygen-carbon dioxide exchange. Two proteins come together to form hemoglobin: heme, a reddish pigment that contains iron, and globin. Hemoglobin bonds loosely with oxygen and carbon dioxide molecules, depending on which is in higher concentration. In the lungs, oxygen molecules have […]

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