katyzzzHemoglobin
December 12th 2006 04:26
Hemoglobin :
The role of the red blood cells is to carry oxygen through the body. The red blood cells can perform this task because of the presence of hemoglobin, the pigment that is formed when the red blood cells develop in the bone marrow.
Each hemoglobin molecule is made up of a protein molecule called globin and four pigmented molecules of a compound called heme. Each heme molecule has one atom of iron, and there are four heme molecules in a single molecule of hemoglobin; hence, a single molecule of hemoglobin has four atoms of iron. This structure makes it possible for one hemoglobin molecule to join with four oxygen molecules to form a substance called oxyhemoglobin. This reaction is reversible, enabling hemoglobin to pick up oxygen when the blood is in the lungs and to release oxygen in the cells when the blood is pumped to the tissues.
In general, the blood of men usually has a greater concentration of hemoglobin than that of women. Men have about 14 to 16 grams of hemoglobin per 100 milliliters of blood, whereas women have only about 12 to 14 grams per 100 milliliters of blood. (One hundred milliliters is approximately equal to 31⁄2 ounces.)
A number of blood disorders have to do with hemoglobin abnormalities. In many forms of anemia, there is not enough hemoglobin in the red blood cells. In polycythemia vera, there is too much hemoglobin in the blood. In other conditions, such as thalassemia, the abnormal chemical composition or production of hemoglobin molecules reduces both the oxygen-carrying and oxygen-releasing capability of the red blood cells.
The role of the red blood cells is to carry oxygen through the body. The red blood cells can perform this task because of the presence of hemoglobin, the pigment that is formed when the red blood cells develop in the bone marrow.
Each hemoglobin molecule is made up of a protein molecule called globin and four pigmented molecules of a compound called heme. Each heme molecule has one atom of iron, and there are four heme molecules in a single molecule of hemoglobin; hence, a single molecule of hemoglobin has four atoms of iron. This structure makes it possible for one hemoglobin molecule to join with four oxygen molecules to form a substance called oxyhemoglobin. This reaction is reversible, enabling hemoglobin to pick up oxygen when the blood is in the lungs and to release oxygen in the cells when the blood is pumped to the tissues.
In general, the blood of men usually has a greater concentration of hemoglobin than that of women. Men have about 14 to 16 grams of hemoglobin per 100 milliliters of blood, whereas women have only about 12 to 14 grams per 100 milliliters of blood. (One hundred milliliters is approximately equal to 31⁄2 ounces.)
A number of blood disorders have to do with hemoglobin abnormalities. In many forms of anemia, there is not enough hemoglobin in the red blood cells. In polycythemia vera, there is too much hemoglobin in the blood. In other conditions, such as thalassemia, the abnormal chemical composition or production of hemoglobin molecules reduces both the oxygen-carrying and oxygen-releasing capability of the red blood cells.
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