| Περίληψη: | Erythrocytes have the form of a biconcave disc; each one contains 30pg of hemoglobin with which it carries out its’ function, i.e, the precisely tuned transfer of oxygen from the lungs to the tissues. This process largely depends on temperature and pH. Red cell Indices (MCH,MCV, MCHC) are precious for the orientation of diagnosis. The hemoglobin molecule is composed of two pairs of polypeptide chains (α and β in the human adult, HbA) which are interwave in space forming an almost spherical molecule. In a specific folding of each chain lies a flat heme molecule whose center is occupied by an iron atom. Oxygen is bound in the space between the iron and a histidine residue of the chain. Iron is absorbed from the gut and deposited in the macrophages of the liver, wherefrom it is delivered to the erythroblasts. The metabolism of iron is extremely complex; hepcidin plays an important role. Red cells survive ca. 120 days in the circulation through effective glycolysis; when old, they are sequestrated and metabolized in the spleen.
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