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(ĭrĭth`rəsīt'): see bloodblood,
fluid pumped by the heart that circulates throughout the body via the arteries, veins, and capillaries (see circulatory system; heart). An adult male of average size normally has about 6 quarts (5.6 liters) of blood.
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a red blood corpuscle, or cell, in man, the vertebrates, and some invertebrates (echinoderms). Erythrocytes transport oxygen from the lungs to the tissues, and carbon dioxide from the tissues to the lungs. They regulate the acid-base balance and maintain osmotic balance in the blood and tissues. In addition, amino acids and lipids are absorbed from the blood plasma, and transported to the tissues, by erythrocytes.

Mature mammalian and human erythrocytes lack the nucleus that is present in the early stages of their development—that is, in the erythroblasts. They have the shape of a biconcave disk. Erythrocytes consist mainly of the respiratory pigment hemoglobin, which is responsible for the red color of blood. The erythrocytes of birds, reptiles, amphibians, and fishes are nucleated. The erythroblasts’ actively functioning nuclei gradually become inactive in the course of the erythrocytes’ development; they can, however, be reactivated. At the same time, ribosomes and other constituents that participate in protein synthesis disappear from the cytoplasm. The cell (or plasma) membrane plays an important role by permitting the passage of gases, ions, and water in the erythrocytes. On the surface of the lipoprotein membrane are specific glycoprotein antigens, or agglutinogens—the blood group factors responsible for the agglutination of erythrocytes.

The efficient functioning of hemoglobin depends on the erythrocytes’ area of surface contact with the environment. The smaller the erythrocytes, the greater their total surface area. The lower invertebrates have large erythrocytes (measuring, for example, 70 micrometers in diameter in the caudate amphibian Amphiuma), and the higher vertebrates have smaller ones (4 micrometers in diameter in goats). Human erythrocytes vary in diameter from 7.2 to 7.5 micrometers.

The number of erythrocytes in the blood normally remains constant, ranging from 4.5 to 5 million in 1 mm3 of human blood. The life-span of a human erythrocyte averages 125 days; approximately 2.5 million erythrocytes are formed and an equal number are destroyed every second. The total number decreases in anemia and increases in polycythemia. In the anemias, erythrocytes are found to change shape and size; they may be large (such as the megalocytes in Addison-Biermer anemia) or small, and they may, for example, be oval in shape (as in hemolytic anemia).



A type of blood cell that contains a nucleus in all vertebrates but humans and that has hemoglobin in the cytoplasm. Also known as red blood cell.


a blood cell of vertebrates that transports oxygen and carbon dioxide, combined with the red pigment haemoglobin, to and from the tissues
References in periodicals archive ?
The ability of plasma samples to inhibit infected erythrocyte binding to CSPG was higher for multigravidae than for primigravidae at inclusion (p<0.
And when lead-exposed erythrocytes were co-cultured with unexposed HK-2 cells, the HK-2 cells not only phagocytized the erythrocytes, but also showed increased production of reactive oxygen species, diminished viability, and greater expression of genes associated with kidney damage.
Having established a method for precise measurements of water within multiple microenvironments, we evaluated the dependence of T2MR signals on hematocrit by measuring samples reconstituted with erythrocytes and plasma isolated from 5 individuals across a range of hematocrit values (20%-85%).
As compared with the pregnant rats, which have drunk the "Aqua Minerale" water (experience 1), in the pregnant rats (experience 3) there is the significant increase in erythrocytes by 15.
2+] activity further triggered scrambling of the erythrocyte membrane resulting in phosphatidylserine exposure at the erythrocyte surface.
5% (v/v) chicken erythrocyte suspension and incubated at 0, 10, 20, 30, 37, 40, or 50[degrees]C for 1 h.
This is a surprising observation regarding these two SGPs, as no report is available about the presence of such SGPs in the human erythrocyte membranes.
The Motic images 2000 software was used to evaluate the radius, perimeter and surface of SS blood erythrocytes before and after treatment with anthocyanins (Table 3).
The increase in the formation of micronucleus indicates that home waste and agricultural pollution can increase the clastogenic effects on peripheral erythrocytes of Cyprinus carpio and could have similar effects on the human population located around the lake or consume fishes from this lake.
Digital analysis of morphometric characteristics of erythrocytes show that such an analysis could be valuable in diagnosing coronary artery disease [7], determining the effect of cholesterol in capillary flow [8], monitoring erythrocyte aggregation [9], and detecting changes in erythrocytes due to blood storage [10].