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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 ?
Automated analyzers are used to count cells, measure hemoglobin levels, and calculate parameters such as the hematocrit and erythrocyte indices.
For the children with four consecutive pieces of hair analyzed (up to ~ 8 cm from the head; n = 19), we assessed the correlations for each 2 cm of hair (n = 17 with erythrocytes and urine analyzed).
Some portion of EDTA-treated blood was also used for scanning electron microscopy (SEM) of erythrocytes.
Micronuclei observed in the mice erythrocytes from all treatments were counted and the means were tabulated in Table 2.
From the same sample, erythrocytes were obtained by centrifugation at 290 x g, fixed with half-strength Karnovsky's fixative and examined using a JEOL JSM 6390LV SEM (JEOL Ltd, Tokyo, Japan) electron microscope.
In the present study MN frequencies in the fish peripheral blood erythrocytes after exposure to different concentrations of OP pesticides (chlorpyrifos, malathion), SP pesticides (cypermethrin, lambda-cyhalothrin) and herbicide (buctril) show increase in frequencies as compared to control group (Figs.
The present study therefore has been undertaken to evaluate the efficacy of black tea and vitamin C to protect erythrocytes from oxidative stress induced by exposure of Wistar rats to a sub-acute dose of carbofuran.
The observation of increased Na+, K+-ATPase activity in response to Tetraphenylporphinesulfonate (TPPS), 5,10,15,20-Tetrakis (4sulfonatophenyl) porphyrinato Iron(III) Chloride (FeTPPS) and 5,10,15,20-Tetrakis (4sulfonatophenyl) porphyrinato Iron(III) nitrosyl Chloride (FeNOTPPS) pre-treatment is interesting since insulin also causes an increase in Na+-K+-ATPase activity in erythrocytes of Diabetics.
Ascorbic acid restores the activity of these enzymes and so the toxic effect of lead on the erythrocytes is reversed.
A reduction in the SPM maintenance in erythrocyte membranes leads to a decrease in protective properties of erythrocytes, the acidotic shifts in blood plasma, a change to electrostatic properties in red blood cells and an increase in permeability of a membrane.
A pertinent initial investigation would be to rigorously compare erythrocyte lifespan between blacks and whites.
The peripheral blood erythrocytes were sampled after 30 day exposure to four different test concentrations and controls, and subjected to Comet bioassay.