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What functions do red blood cells perform, how long do they live and where are they destroyed? Normal and pathological forms of human red blood cells (poikilocytosis) Red blood cells with nuclei

Shape and number of red blood cells. In humans and many mammals, they are anucleate cells of a biconcave shape. They are elastic, which helps them pass through narrow capillaries. The diameter of a human red blood cell is 7-8 microns, and the thickness is 2-2.5 microns. The absence of a nucleus and the shape of a biconcave lens (the surface of a biconcave lens is 1.6 times larger than the surface of a sphere) increase the surface of the red blood cells, and also ensure rapid and uniform diffusion of oxygen into the red blood cell.

In the blood of humans and higher animals, young ones contain nuclei. During the process of red blood cell maturation, the nuclei disappear.

Rice. 45. Goryaev's counting chamber:

1 - top view; 2 - side view; 3 - Goryaev’s grid; 4 - mixer

General The surface of all human red blood cells is more than 3000 m2, which is 1500 times the surface of his body.

The total number of red blood cells found in human blood is enormous. It is approximately 10 thousand times larger than the population of our planet. If you lined up all the people in one row, you would get a chain about 150,000 km long, but if you put red blood cells one on top of the other, you would form a column with a height exceeding the length of the equator of the globe (50,000 -60,000 km).

1 mm of blood contains from 4 to 5 million red blood cells (in women - 4.0-4.5 million, men - 4.5-5.0 million). The number of red blood cells is not strictly constant. It can increase significantly with a lack of oxygen at high altitudes and during muscular work. People living in high mountain areas have approximately 30% more red blood cells than residents of the sea coast. When moving from lowland to highland areas, the number of red blood cells in the blood increases. When the need for oxygen decreases, the number of red blood cells in the blood decreases.

Table 8

Age-related changes in the number of red blood cells

Age Number of red blood cells in1 mm 3 crosi
average fluctuations
At birth 5 250 000 4 500 000-6 000 000
1st day of life 6 000 000 5 000 000-7 500 000
1st month of life 4 700 000 3 500 000-5 600 000
6th month of life 4 100 000 3 500 000-5 000 000
2-4 years 4 600 000 4 000 000-5 200 000
10-15 years 4 800 000 4 200 000-5 300 000
Adult 5 000 000 4 000 000-5 500 000

Red blood cells are counted using special counting chambers (Fig. 45).

To count the formed elements, the sample taken from the finger is diluted in special mixers to create the desiredcell concentration convenient for counting. To dilute the blood when counting red blood cells, a hypertonic (3%) NaCl solution is used, in which the red blood cells shrink.

The mixer (melanger) consists of a graduated capillary tube with an ovoid extension (ampule). A glass bead is placed in the ampoule for better mixing of the blood (Fig. 45, 4). Mixers are available for counting red and white blood cells. In mixers for red blood cells, the bead inside the ampoule is colored red, and for white blood cells, it is white. The capillary of the mixers has marks 0.5 and 1.0; they indicate half or the whole volume of the capillary. Above the ovoid dilatation, the 101 mark in the RBC mixer indicates that the dilatation cavity has a volume 100 times greater than the volume of the capillary cavity. The leukocyte mixer has a mark 11, indicating that the expansion cavity is 10 times larger than the total volume of the capillary. When the red blood cell mixer is filled to the 1.0 mark and then diluted with 3% NaCl solution, bringing the total volume to the 101 mark, it will be diluted 100 times. When diluting 200 times, draw blood in the mixer capillary to the 0.5 mark and add diluting liquid to the 101 mark.

Before use, the mixer must be thoroughly washed and dried by blowing air using a water jet pump or a rubber bulb. Whether the mixer is dry enough is determined by the movement of the bead in the ampoule: sticking of the bead to the walls indicates the presence of moisture.

The counting chamber is a thick object, on the upper surface of which there are three transverse platforms, separated by recesses (Fig. 45, 1, 2). The middle platform is 0.1 mm lower than the outer ones, and when a cover glass is placed on the side platforms, a chamber 0.1 mm deep is formed above the mesh of the middle platform. Goryaev's chamber has a transverse groove on the middle platform. On both sides of this groove there is a square mesh, cut by a special dividing machine. The reticle may have a different pattern depending on the camera design. The grid of Goryaev's chamber has 225 large squares, 25 of which are divided into 16 small squares each. The sizes of small squares in a chamber of any design are the same. The side of a small square is 1/20 mm, therefore its area is(1/20) (1/20) = 1/400 mm 2. Considering that the camera height(distance from the middle platform to the cover glass) is equal to1/10mm, the volume above the small square is (1/400) (1/10) = 1/4000 mm 3.

Pour blood dilution solution (3% NaCl solution) into a cup. Prick your finger with a needle and dip the tip of the faucet into the blood that appears. Place the tip of the mixer in your mouth and pump the blood to the 0.5 mark. It is necessary to ensure that no air bubbles enter the capillary. To do this, the tip of the capillary must be immersed in a drop of blood until the end of suction. Do not press the faucet against your finger so as not to clog the faucet hole. You need to try to prevent the blood from rising above the indicated mark on the mixer, but if this happens, you can carefully lower the tip of the capillary onto cotton wool or filter paper, and the blood level will drop. Of course, the calculation error will increase. Then quickly immerse the tip of the capillary in the dilution liquid (3% NaCl solution). Without releasing the blood from the mixer, pump the dilution solution into it with your mouth until the 101 mark. The blood will now be diluted 200 times. Having finished collecting the liquid, move the mixer to a horizontal position, remove the rubber tube, close the capillary at both ends with your thumb and forefinger and thoroughly mix the liquid in the extension of the mixer. Now place the mixer in a horizontal position on the table.

Press the coverslip tightly onto the edges of the counting chamber so that it does not fall when the chamber is tipped over. From the mixer, release 2-3 drops of liquid onto cotton wool or filter paper, and release the next drop from the tip of the capillary under the cover glass into the counting chamber. Due to capillarity, the mixture should fill it evenly, and the position of the cover glass should not change. If the glass “floats up,” wipe the camera thoroughly and repeat the filling procedure. Place the filled chamber under the microscope.

At low magnification (15x eyepiece), count the red blood cells in 80 small squares, which corresponds to five large, frequently graphed squares; Select 5 large squares diagonally across the entire counting chamber. This is done in order to reduce the error associated with uneven filling of the chamber.

To make it easier to count red blood cells, draw 5 large squares on a piece of paper, and divide each of them into 16 small squares. After counting the number of red blood cells in each small square under a microscope, write this value in the squares on paper.

For In order not to make a mistake in counting and not to count red blood cells twice that lie on the borders between small squares, use the following rule: red blood cells lying inside the square and on its left and upper borders are considered to belong to a given square. Red blood cells lying on the right and lower borders of the square are not counted.

Having thus counted the number of red blood cells in five large squares (80 small squares), find the arithmetic mean of the number of red blood cells in one small square.

The volume of liquid above one is taken as the starting point for further calculations.with a small square. Since it is equal to 1/4000 mm 3, then the amount of erythrocyts in 1 mm 3 of blood can be calculated by multiplying the average number of red blood cells in a small square by 4000 and by the value of blood dilution. For calculation it is convenient to use the following formula:

where E is the number of red blood cells per 1 mm3; n - the number of red blood cells counted in 80 small squares; 200 - blood dilution.

Having finished counting red blood cells, you need to wash the counting chamber and wipe it dry with clean gauze.

Aging and death of red blood cells

The average lifespan of red blood cells is 100-120 days. As we age, towards the end of our life cycle, passing through the small blood vessels of the liver or spleen, red blood cells adhere to the cells lining the inner surface of the vessels. These are reticuloendothelial cells. They are capable of phagocytosis. They capture not only aged red blood cells, but also foreign particles. In a healthy person, the spleen destroys only old or accidentally damaged red blood cells. With aging or damage, red blood cells lose their elasticity and therefore can no longer overcome the resistance of capillary vessels; they are retained in the spleen and are absorbed by reticuloendothelial cells.

After the breakdown of red blood cells from hemoglobin, the pigment bilirubin is formed in the liver. Once in the intestines as part of bile, bilirubin is reduced into the pigments stercobilin, which colors stool brown, and urobilin, which gives urine its characteristic color. By the amount of these pigments in feces and urine, one can calculate the daily breakdown of hemoglobin in the body and judge the amount of destruction of red blood cells.

Released after the breakdown of hemoglobin, it is deposited in the liver and spleen as a reserve and, as needed, from here enters the bone marrow, where it is again included in hemoglobin molecules.

In a healthy person, the breakdown of red blood cells releases 20-30 mg of iron per day, which is the daily iron requirement of an adult.

The meaning of red blood cells. The main function of red blood cells is to carry oxygen from the lungs to all cells of the body. Found in red blood cells, it easily combines with oxygen and easily releases it under certain conditions.

The role of red blood cells is also great in removing carbon dioxide from tissues. With their participation, carbon dioxide formed during the life of cells is converted into carbon dioxide salts, which constantly circulate in the blood. IN In the capillaries of the lungs, these salts, again with the obligatory participation of red blood cells, break down to form carbon dioxide and water. Carbon dioxide and part of the water are immediately removed from the body through the respiratory tract.

Red blood cells maintain the relative constancy of the blood gas composition. When their function is disrupted in the internal environment of the body, the carbon dioxide content sharply increases and oxygen deficiency develops, which has a detrimental effect on the activity of the entire organism.

Hemoglobin

Red blood cells contain a protein substance - , giving blood a red color. Red blood cells are more than 90% hemoglobin. consists of a protein part - globin and non-protein -(prosthetic group) containing divalent . In the capillaries of the lungs, hemoglobin combines with oxygen to form oxyhemoglobin. Hemoglobin owes its ability to combine with oxygen to heme, or more precisely, to the presence of divalent iron in its composition.

In tissue capillaries, oxyhemoglobin easily disintegrates to release oxygen and hemoglobin. This is facilitated by the high content of carbon dioxide in tissues.

Oxyhemoglobin is bright red and hemoglobin is dark red. This explains the difference in color between venous and arterial blood.

Oxyhemoglobin has the properties of a weak acid, which is important in maintaining a constant blood reaction (pH).

Hemoglobin can also form a compound with carbon dioxide. This process occurs in tissue capillaries. In the capillaries of the lungs, where the carbon dioxide content is much less than in the capillaries of tissues, the combination of hemoglobin with carbon dioxide breaks down. Thus, hemoglobin is transferred not only from the lungs to the tissues. It is also involved in the transfer of carbon dioxide.

Hemoglobin binds most strongly to carbon monoxide (CO). When the air contains 0.1% carbon monoxide, more than half of the hemoglobin in the blood combines with carbon monoxide, and therefore cells and tissues are not provided with the necessary amount of oxygen. As a result of oxygen starvation, muscle weakness, loss of consciousness, convulsions occur, and death may occur. First aid for carbon monoxide poisoning is to provide a flow of clean air, give the victim strong tea, and then medical attention is needed.

At 100 ml The blood of an adult contains 13-16 g of hemoglobin. How can we understand this? After all, they often say that the hemoglobin content in the blood is 65-80%. But the fact is that in medical practice, the hemoglobin content is taken as 100, equal to 16.7 g per 100 cm 3 of blood. Typically, the blood of an adult does not contain 100% hemoglobin, but somewhat less - 60-80%. Therefore, if a blood test says “80 units of hemoglobin,” this means that 100 ml of blood contains 80% of 16.7 g, i.e., about 13.4 g of hemoglobin.

A high level of hemoglobin (over 100%) and a large number of red blood cells (about 6,000,000) are observed in newborns; by the 5-6th day of his life, these indicators decrease, which is associated with the hematopoietic function of the bone marrow. Then, by 3-4 years, the amount of hemoglobin and red blood cells increases slightly. At 6-7 years of age, due to rapid growth, there is a slowdown in the increase in the number of red blood cells and heme contentglobin. From the age of 8, there is an increase in the number of red blood cells and the amount of hemoglobin.

The amount of hemoglobin is determined using a colorimetric method based on the following principle. If the test solution is brought to a color identical to the standard solution by dilution, then the concentration of dissolved substances in both solutions will be the same, and the amounts of substances will be related to their volumes. Knowing the amount in the standard solution, you can calculate its content in the test solution. A device for determining the amount of hemoglobin in the blood is called hemometer.

Rice. 46.

The hemometer (Fig. 46) is a tripod; The back wall is made of milky glass. Three test tubes of the same diameter are inserted into a rack. The two outermost ones are sealed and contain a standard solution of hematin hydrochloride (a compound of hemoglobin with hydrochloric acid). The middle tube is graduated and open at the top. It is intended for the blood being tested. A 20 mm 3 pipette and a thin glass rod are attached to the device. RustThe thief taken for the standard contains 16.7 g of hemoglobin in 100 cm 3 of blood. This hemoglobin content is considered the highest limit of normal and is taken as 100%, or hemometric units. To conduct the study, convert the hemoglobin of the test blood into hematin hydrochloride. This substance is brown in color, and its standard solution has the color of strong tea.

Pour 0.1 normal hydrochloric acid solution into the middle tube of the hemometer up to the 10 mark. Using the special pipette supplied with the hemometer, take 20 mm3 of blood; After wiping the tip of the pipette with a cotton swab (the blood level in it should not change), carefully blow the blood onto the bottom of the test tube with hydrochloric acid. Without removing the pipette from the test tube, rinse it several times with hydrochloric acid. Finally, touch the pipette to the side of the tube and carefully blow out the contents. Leave the solution for 5-10 minutes, stirring it with a glass rod. This time is necessary for the complete conversion of hemoglobin into hematin hydrochloride. Then add distilled water drop by drop into the middle test tube with a pipette until the color of the resulting solution is the same as the color of the standard (while adding water, mix the solution with a stick). Be especially careful when adding the last drops.

The number located at the level of the surface of the solution in the middle test tube will show the hemoglobin content in the test blood as a percentage relative to the norm, conventionally accepted as 100%.

Erythrocyte sedimentation reaction (ESR)

If the blood is protected from clotting and left for several hours in the capillary tubes, then the red blood cells in the blood begin to settle due to gravity. They settle at a certain speed. In women, the normal erythrocyte sedimentation rate is 7-12 mm per hour, and in men it is 3-9 mm per hour.

Determination of erythrocyte sedimentation rate has important diagnostic value in medicine. With tuberculosis and various inflammatory processes in the body, the erythrocyte sedimentation rate increases.

The erythrocyte sedimentation rate (ERS) is determined using a Panchenkov device (Fig. 47).

Rice. 47.

The device is a tripod in which capillary tubes are mounted in a vertical position. Capillaries are divided in millimeters. In addition, there are three more marks on the capillary: mark TO(blood), mark R(reagent) and label ABOUT, which is flush with the mark TO. To prevent blood from clotting, take a 5% solution of sodium citrate (citrate). First rinse the capillary with this solution, and then draw it into the capillary up to the mark R(reagent). Blow the anticoagulant solution from the capillary onto the watch glass.

Pierce the skin of your finger with a needle and draw blood into the same capillary up to the mark TO(blood). Blow blood from the capillary onto a watch glass, mixing it with the sodium citrate solution available there. When filling the capillary with blood, it is important that no air bubbles burst into it. To do this, make a finger puncture deeper than usual, and, immersing the tip of the capillary in the base of a drop of blood, move the capillary to a horizontal position. Now, according to the law of capillarity, the blood itself will fill the capillary. Draw the resulting mixture of blood with sodium citrate into the capillary up to the mark

The role of blood in respiration. Methods for studying blood gases. For the first time, I.M. Sechenov succeeded in 1858 with the help of...

erythrocytes The erythrocytes of many mammals and humans are round, biconcave, anucleate cells. The diameter of human red blood cells is 7 - 8μ, and the thickness...

Erythrocytes, or red blood cells, are cells that in humans and mammals lack a nucleus and have homogeneous protoplasm.

The structure of the erythrocyte is divided into stroma - the skeleton of the cell and the surface layer - the membrane. The membrane of erythrocytes is formed by lipid-protein complexes; it is impermeable to colloids and K˙ and Na˙ ions and is easily permeable to the anions Cl", HCO"3, as well as H˙ and OH ions." The mineral composition of erythrocytes and plasma is not the same: in human erythrocytes there is more potassium than sodium; in plasma There is an inverse ratio of these salts: 90% of the dry matter of erythrocytes is hemoglobin, and the remaining 10% is other proteins, lipoids, glucose and mineral salts.

For physiology and clinical purposes, the determination of the number of red blood cells in the blood, which is performed under a microscope using counting cameras or using automatically operating electronic devices, has become important.

1 mm3 of blood in men contains about 5,000,000 red blood cells, in women - about 4,500,000. In newborns, the number of red blood cells is greater than in adults.

The number of red blood cells in the blood may change. It increases with low barometric pressure (when rising to heights), with muscular work, emotional arousal, and also with a large loss of water from the body. An increase in the number of red blood cells in the blood can last for different periods of time and does not necessarily indicate an increase in their total number in the body. Thus, with a large loss of water, caused, for example, by profuse sweating, a short-term thickening of the blood occurs, as a result of which the number of red blood cells per unit volume increases, although their absolute number in the body does not change. With emotional excitement and heavy muscular work, the number of red blood cells in the blood increases due to contraction of the spleen and the entry of blood rich in red blood cells from the splenic blood depot into the general bloodstream.

An increase in the number of red blood cells in the blood under conditions of low barometric pressure is due to a reduced supply of oxygen to the blood. In people living in high mountains, the number of red blood cells increases due to their increased production by the bone marrow, a hematopoietic organ (Fig. 3). In this case, not only the number of red blood cells per unit volume of blood increases, but also their total number in the body.

A decrease in the number of red blood cells in the blood - anemia - is observed after blood loss or due to increased destruction of red blood cells or weakening of their formation.

The diameter of an individual human red blood cell is 7.2-7.5 microns, and its volume is approximately 88-90 microns. The size of an individual red blood cell and their total number in the blood determine the size of their total surface. This value is of great importance, since it determines the total surface on which oxygen absorption and release occur, i.e.
a process that is the main physiological function of red blood cells.

The total surface of all human red blood cells reaches approximately 3000 mg, i.e. 1500 times the surface of the entire body. Such a large surface is facilitated by the peculiar shape of the red blood cell. Human red blood cells have a flattened shape with depressions inward in the middle on both sides (Fig. 4). With this shape, there is not a single point in the erythrocyte that would be more than 0.85 μm from its surface, while with a spherical shape, the center of the cell would be at a distance of 2.5 μm from it, and the total surface would be 20% less. Such surface-to-volume ratios contribute to better performance of the main function of the red blood cell - the transfer of oxygen from the respiratory organs to the cells of the body.

This function is carried out due to the presence in the erythrocyte of the respiratory pigment of blood - hemoglobin.

The fact that hemoglobin is located inside red blood cells, and not in a dissolved state in the blood plasma, has important physiological significance. As a result of this:

1. Blood viscosity decreases. Calculations show that dissolving the same amount of hemoglobin in blood plasma would increase blood viscosity several times and would sharply impede the work of the heart and blood circulation.

2. The oncotic pressure of the blood plasma decreases, which is important to prevent tissue dehydration (due to the transition of tissue water into the blood plasma).

And then they distribute it (oxygen) throughout the animal’s body.

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    Red blood cells are highly specialized cells whose function is to transport oxygen from the lungs to body tissues and transport carbon dioxide (CO 2 ) in the opposite direction. In vertebrates, except mammals, red blood cells have a nucleus; in mammalian red blood cells there is no nucleus.

    Mammalian erythrocytes are the most specialized, deprived of a nucleus and organelles in the mature state and having the shape of a biconcave disk, which determines a high area-to-volume ratio, which facilitates gas exchange. Features of the cytoskeleton and cell membrane allow red blood cells to undergo significant deformations and restore their shape (human red blood cells with a diameter of 8 microns pass through capillaries with a diameter of 2-3 microns).

    Oxygen transport is provided by hemoglobin (Hb), which accounts for ≈98% of the mass of proteins in the cytoplasm of erythrocytes (in the absence of other structural components). Hemoglobin is a tetramer in which each protein chain carries a heme complex of protoporphyrin IX with a ferrous ion, oxygen is reversibly coordinated with the Fe 2+ ion of hemoglobin, forming oxyhemoglobin HbO 2:

    Hb + O 2 HbO 2

    A feature of the binding of oxygen by hemoglobin is its allosteric regulation - the stability of oxyhemoglobin decreases in the presence of 2,3-diphosphoglyceric acid, an intermediate product of glycolysis and, to a lesser extent, carbon dioxide, which promotes the release of oxygen in tissues that need it.

    Transport of carbon dioxide by erythrocytes occurs with the participation carbonic anhydrase 1 contained in their cytoplasm. This enzyme catalyzes the reversible formation of bicarbonate from water and carbon dioxide that diffuses into red blood cells:

    H2O+CO2 ⇌ (\displaystyle \rightleftharpoons ) H + + HCO 3 -

    As a result, hydrogen ions accumulate in the cytoplasm, but the decrease is insignificant due to the high buffer capacity of hemoglobin. Due to the accumulation of bicarbonate ions in the cytoplasm, a concentration gradient arises, however, bicarbonate ions can leave the cell only if an equilibrium charge distribution is maintained between the internal and external environments, separated by the cytoplasmic membrane, that is, the exit of the bicarbonate ion from the erythrocyte must be accompanied by either the exit of the cation or the entry of the anion. The erythrocyte membrane is practically impermeable to cations, but contains chloride ion channels, as a result, the exit of bicarbonate from the erythrocyte is accompanied by the entry of chloride anion into it (chloride shift).

    Formation of red blood cells

    Colony-forming unit of erythrocytes (CFU-E) gives rise to erythroblast, which, through the formation of pronormoblasts, already gives rise to morphologically distinguishable descendant cells normoblasts (successively passing stages):

    • Erythroblast. Its distinctive features are as follows: diameter 20-25 microns, large (more than 2/3 of the entire cell) nucleus with 1-4 clearly defined nucleoli, bright basophilic cytoplasm with a purple tint. Around the nucleus there is clearing of the cytoplasm (the so-called “perinuclear clearing”), and protrusions of the cytoplasm (the so-called “ears”) can form at the periphery. The last 2 signs, although characteristic of etitroblasts, are not observed in all of them.
    • Pronormocyte. Distinctive features: diameter 10-20 microns, the nucleus is deprived of nucleoli, chromatin becomes coarser. The cytoplasm begins to lighten, the perinuclear clearing increases in size.
    • Basophilic normoblast. Distinctive features: diameter 10-18 microns, nucleus devoid of nucleoli. Chromatin begins to segment, which leads to uneven perception of dyes and the formation of zones of oxy- and basochromatin (the so-called “wheel-shaped nucleus”).
    • Polychromatophilic normoblast. Distinctive features: diameter 9-12 microns, pyknotic (destructive) changes begin in the core, but the wheel shape remains. The cytoplasm becomes oxyphilic due to the high concentration of hemoglobin.
    • Oxyphilic normoblast. Distinctive features: diameter 7-10 microns, the nucleus is subject to pyknosis and is shifted to the periphery of the cell. The cytoplasm is clearly pink; fragments of chromatin (Joly bodies) are found in it near the nucleus.
    • Reticulocyte. Distinctive features: diameter 9-11 microns, with supravital coloring it has yellow-green cytoplasm and blue-violet reticulum. When stained according to Romanovsky-Giemsa, no distinctive features are revealed in comparison with a mature erythrocyte. When studying the usefulness, speed and adequacy of erythropoiesis, a special analysis of the number of reticulocytes is carried out.
    • Normocyte. A mature erythrocyte, with a diameter of 7-8 microns, without a nucleus (clearance in the center), the cytoplasm is pink-red.

    Hemoglobin begins to accumulate already at the CFU-E stage, but its concentration becomes high enough to change the color of the cell only at the level of a polychromatophilic normocyte. The same happens with the extinction (and subsequently destruction) of the nucleus - with CFU, but it is displaced only in the later stages. An important role in this process in humans is played by hemoglobin (its main type is Hb-A), which in high concentrations is toxic to the cell itself.

    Structure and composition

    In most groups of vertebrates, red blood cells have a nucleus and other organelles.

    In mammals, mature red blood cells lack nuclei, internal membranes, and most organelles. Nuclei are released from progenitor cells during erythropoiesis. Typically, mammalian red blood cells are shaped like a biconcave disc and contain primarily the respiratory pigment hemoglobin. In some animals (for example, camels), red blood cells are oval in shape.

    The contents of the red blood cell are represented mainly by the respiratory pigment hemoglobin, which causes the red color of the blood. However, in the early stages the amount of hemoglobin in them is small, and at the erythroblast stage the cell color is blue; later, the cell becomes gray and only when fully matured, it acquires a red color.

    An important role in the erythrocyte is played by the cellular (plasma) membrane, which allows gases (oxygen, carbon dioxide), ions ( , ) and water to pass through. The membrane is penetrated by transmembrane proteins - glycophorins, which, due to the large number of N-acetylneuraminic (sialic) acid residues, are responsible for approximately 60% of the negative charge on the surface of erythrocytes.

    On the surface of the lipoprotein membrane there are specific antigens of a glycoprotein nature - agglutinogens - factors of blood group systems (more than 15 blood group systems have been studied so far: A0, Rh factor, Duffy antigen (English) Russian, antigen Kell , antigen Kidd (English) Russian), causing agglutination of erythrocytes under the action of specific agglutinins.

    The efficiency of hemoglobin functioning depends on the size of the surface of contact of the erythrocyte with the environment. The total surface area of ​​all red blood cells in the body is greater, the smaller their size. In lower vertebrates, erythrocytes are large (for example, in the tailed amphibian Amphium - 70 microns in diameter), the erythrocytes of higher vertebrates are smaller (for example, in a goat - 4 microns in diameter). In humans, the diameter of an erythrocyte is 6.2-8.2 microns, thickness - 2 microns, volume - 76-110 microns³.

    • in men - 3.9-5.5⋅10 12 per liter (3.9-5.5 million in 1 mm³),
    • for women - 3.9-4.7⋅10 12 per liter (3.9-4.7 million in 1 mm³),
    • in newborns - up to 6.0⋅10 12 per liter (up to 6 million in 1 mm³),
    • in older people - 4.0⋅10 12 per liter (less than 4 million per 1 mm³).

    Blood transfusion

    The average lifespan of a human erythrocyte is 125 days (about 2.5 million erythrocytes are formed every second and the same number are destroyed), in dogs - 107 days, in domestic rabbits and cats - 68.

    Pathology

    With various blood diseases, changes in the color of red blood cells, their size, quantity, and shape are possible; they can take, for example, crescent-shaped, oval, spherical or target-shaped.

    The change in the shape of red blood cells is called poikilocytosis. Spherocytosis (spherical shape of red blood cells) is observed in some forms of hereditary

    In various situations, when making certain diagnoses, doctors often strongly recommend that we take a blood test. It is very informative and allows you to evaluate the protective properties of our body in case of a particular illness. There are quite a lot of indicators in it, one of them is the volume of red blood cells. Many of you have probably never thought about this. But in vain. After all, everything is thought out by nature to the smallest detail. The same is the case with red blood cells. Let's take a closer look.

    What are red blood cells?

    Red blood cells play an important role in the human body. Their main task is to supply oxygen, which is supplied during breathing to all tissues and organs of our body. The carbon dioxide formed in this situation must be urgently removed from the body, and here the red blood cell is the main assistant. By the way, these blood cells also enrich our body with nutrients. Red blood cells contain a well-known red pigment called hemoglobin. It is he who is able to bind oxygen in the lungs for its more convenient removal, and to release it in the tissues. Of course, like any other indicator in the human body, the number of red blood cells can decrease or increase. And there are reasons for this:

    • an increase in the number of blood cells in the blood indicates severe dehydration of the body or (erythremia);
    • a decrease in this indicator will indicate anemia (this is not a disease, but this blood condition can contribute to the development of a large number of other diseases);
    • By the way, oddly enough, red blood cells are often detected in the urine of patients who complain of problems with the urinary system (bladder, kidneys, etc.).

    A very interesting fact: the size of a red blood cell can sometimes change significantly, this happens due to the elasticity of these cells. For example, the diameter of a capillary through which a red blood cell measuring 8 microns can pass is only 2-3 microns.

    Functions of red blood cells

    It would seem that a small red blood cell can do anything useful in such a large human body. But the size of the red blood cell does not matter here. It is important that these cells perform vital functions:

    • Protect the body from toxins: bind them for subsequent removal. This happens due to the presence of protein substances on the surface of red blood cells.
    • They carry enzymes, called specific protein catalysts in the medical literature, to cells and tissues.
    • They are responsible for human breathing. This happens for a reason (it is able to attach and release oxygen, as well as carbon dioxide).
    • Red blood cells nourish the body with amino acids, which they easily transport from the gastrointestinal tract to cells and tissues.

    Place of formation of red blood cells

    It is important to know where red blood cells are formed so that if problems arise with their concentration in the blood, you can take timely measures. The process of creating them is complex.

    The place of formation of red blood cells is the bone marrow, spine and ribs. Let's take a closer look at the first of them: first, brain tissue grows due to cell division. Later, from the cells that are responsible for creating the entire human circulatory system, one large red body is formed, which has a nucleus and hemoglobin. From it the precursor of the red blood cell (reticulocyte) is directly obtained, which, upon entering the blood, is transformed into an erythrocyte in 2-3 hours.

    Structure of a red blood cell

    Since red blood cells contain large amounts of hemoglobin, this causes their bright red color. In this case, the cell has a biconcave shape. The structure of erythrocytes of immature cells provides for the presence of a nucleus, which cannot be said about the finally formed body. The diameter of red blood cells is 7-8 microns, and the thickness is less - 2-2.5 microns. The fact that mature red blood cells no longer have a nucleus allows oxygen to penetrate into them faster. The total number of red blood cells found in human blood is very large. If they are folded into one line, then its length will be about 150 thousand km. Various terms are used for red blood cells to characterize deviations in their size, color and other characteristics:

    • normocytosis - normal average size;
    • microcytosis - size less than normal;
    • macrocytosis - size larger than normal;
    • anitocytosis - in this case, the size of the cells varies significantly, i.e. some of them are too large, others are too small;
    • hypochromia - when the amount of hemoglobin in red blood cells is less than normal;
    • poikilocytosis - the shape of the cells is significantly changed, some of them are oval, others are sickle-shaped;
    • normochromia - the amount of hemoglobin in the cells is normal, which is why they are colored correctly.

    How does a red blood cell live?

    From the above, we have already found out that the place of formation of red blood cells is the bone marrow of the skull, ribs and spine. But once in the blood, how long do these cells stay there? Scientists have found that the life of a red blood cell is quite short - on average about 120 days (4 months). By this time he begins to age for two reasons. This is the metabolism (breakdown) of glucose and an increase in the content of fatty acids. The red blood cell begins to lose energy and elasticity of the membrane, because of this, numerous outgrowths appear on it. Most often, red blood cells are destroyed inside the blood vessels or in some organs (liver, spleen, bone marrow). Compounds formed as a result of the breakdown of red blood cells are easily excreted from the human body through urine and feces.

    The latter of them less often shows the presence of red cells, and often this is due precisely to the presence of some kind of pathology. But human blood always contains red blood cells, and it is important to know the norms of this indicator. The distribution of red blood cells in the blood of an absolutely healthy person is even, and their content is quite high. That is, if he had the opportunity to count their entire number, he would get a huge number that does not carry any information. Therefore, in the course of laboratory research, it is customary to use the following method: count red blood cells in a certain volume (1 cubic millimeter of blood). By the way, this value will allow you to correctly assess the level of red blood cells and identify existing pathologies or health problems. It is important that it is particularly influenced by the patient’s place of residence, his gender and age.

    Norms of red blood cells in the blood

    A healthy person rarely experiences any deviations in this indicator throughout his life.

    So, there are the following norms for children:

    • the first 24 hours of a baby’s life - 4.3-7.6 million/1 cubic meter. mm blood;
    • first month of life - 3.8-5.6 million/1 cubic meter. mm blood;
    • the first 6 months of a child’s life - 3.5-4.8 million/1 cubic meter. mm blood;
    • during the 1st year of life - 3.6-4.9 million/1 cubic meter. mm blood;
    • 1 year - 12 years - 3.5-4.7 million/1 cubic meter. mm blood;
    • after 13 years - 3.6-5.1 million/1 cubic meter. mm of blood.

    The large number of red blood cells in the baby’s blood is easy to explain. When he is in his mother’s womb, his formation of red blood cells occurs at an accelerated rate, because this is the only way all his cells and tissues can receive the required amount of oxygen and nutrients for their growth and development. When a baby is born, red blood cells begin to rapidly break down, and their concentration in the blood decreases (if this process is too fast, the baby develops jaundice).

    • Men: 4.5-5.5 million/1 cubic meter. mm of blood.
    • Women: 3.7-4.7 million/1 cubic meter. mm of blood.
    • Elderly people: less than 4 million/1 cubic meter. mm of blood.

    Of course, a deviation from the norm may be associated with some problem in the human body, but here consultation with a specialist is definitely necessary.

    Red blood cells in urine - can this situation arise?

    Yes, the doctors’ answer is definitely positive. Of course, in rare cases this may occur due to the fact that the person was carrying a heavy load or was in an upright position for a long time. But often an increased concentration of red blood cells in the urine indicates the presence of problems and requires consultation with a competent specialist. Remember some of its norms in this substance:

    • the normal value should be 0-2 pcs. in sight;
    • when a urine test is carried out using the Nechiporenko method, there may be more than a thousand red blood cells per laboratory assistant;

    If a patient has such urine tests, the doctor will look for the specific reason for the appearance of red blood cells in it, allowing for the following options:

    • if we are talking about children, then pyelonephritis, cystitis, glomerulonephritis are considered;
    • urethritis (the presence of other symptoms is also taken into account: pain in the lower abdomen, painful urination, increased body temperature);
    • urolithiasis: the patient simultaneously complains of blood in the urine and attacks of renal colic;
    • glomerulonephritis, pyelonephritis (lower back pain and temperature rises);
    • kidney tumors;
    • prostate adenoma.

    Changes in the number of red blood cells in the blood: reasons

    It assumes the presence in them of a large amount of hemoglobin, which means a substance capable of attaching oxygen and removing carbon dioxide.

    Therefore, deviations from the norm characterizing the number of red blood cells in the blood can be dangerous to your health. in human blood (erythrocytosis) is not often observed and can be associated with some simple reasons: stress, excessive physical activity, or living in a mountainous area. But if this is not the case, pay attention to the following diseases that cause an increase in this indicator:

    • Blood problems, including erythremia. Usually a person has a red coloration of the skin of the neck and face.
    • Development of pathologies in the lungs and cardiovascular system.

    A decrease in the number of red blood cells, medically called erythropenia, can also be caused by several reasons. First of all, it is anemia, or anemia. It may be associated with impaired formation of red blood cells in the bone marrow. When a person loses a certain amount of blood or red blood cells are destroyed too quickly in his blood, this situation also arises. Doctors often diagnose patients with iron deficiency anemia. Iron may simply not enter the human body in sufficient quantities or be poorly absorbed by it. Most often, to correct the situation, experts prescribe vitamin B 12 and folic acid to patients along with iron-containing drugs.

    ESR indicator: what does it mean?

    Often, a doctor, having seen a patient who complains of some kind of cold (which has not gone away for a long time), prescribes a general blood test.

    In it, often on the very last line you will see an interesting indicator of red blood cells, characterizing their sedimentation rate (ESR). How can such research be carried out in a laboratory? It’s very easy: the patient’s blood is placed in a thin glass tube and left in an upright position for a while. Red blood cells will certainly settle to the bottom, leaving clear plasma in the upper layer of blood. The unit of erythrocyte sedimentation is mm/hour. This indicator may vary depending on gender and age, for example:

    • children: 1-month-old babies - 4-8 mm/hour; 6 months - 4-10 mm/hour; 1 year-12 years - 4-12 mm/hour;
    • men: 1-10 mm/hour;
    • women: 2-15 mm/hour; pregnant women - 45 mm/hour.

    How informative is this indicator? Of course, recently doctors have begun to pay less and less attention to him. It is believed that there are many errors in it, which can be associated, for example, in children, with an excited state (screaming, crying) during blood collection. But in general, an increased erythrocyte sedimentation rate is the result of an inflammatory process developing in your body (say, bronchitis, pneumonia, any other cold or infectious disease). Also, an increase in ESR is observed during pregnancy, menstruation, chronic pathologies or diseases that a person has, as well as injuries, stroke, heart attack, etc. Of course, a decrease in ESR is observed much less frequently and already indicates the presence of more serious problems: leukemia, hepatitis, hyperbilirubinemia, and others.

    As we have found out, the place of formation of red blood cells is the bone marrow, ribs and spine. Therefore, if there are problems with the number of red blood cells in the blood, you should first pay attention to the first of them. Every person needs to clearly understand that all the indicators in the tests that we take are very important for our body, and it is better not to treat them negligently. Therefore, if you have completed such a study, please contact a competent specialist to decipher it. This does not mean that at the slightest deviation from the norm in the analysis you should immediately panic. Just follow through, especially when it comes to your health.

    Blood consists of plasma (a transparent liquid of pale yellow color) and cellular, or formed, elements suspended in it - red blood cells, leukocytes and blood platelets - platelets.

    Most of the blood contains red blood cells. In a woman, 1 mm sq. blood contains about 4.5 million of these blood cells, and a man has about 5 million. In general, the blood circulating in the human body contains 25 trillion red blood cells - this is an unimaginably large amount!

    The main function of red blood cells is to carry oxygen from the respiratory system to all cells of the body. At the same time, they also take part in the removal of carbon dioxide (a metabolic product) from tissues. These blood cells transport carbon dioxide to the lungs, where gas exchange replaces it with oxygen.

    Unlike other cells in the body, red blood cells do not have a nucleus, meaning they cannot reproduce. It takes about 4 months from the moment new red blood cells appear until they die. Red blood cells have the shape of oval disks pressed in the middle, approximately 0.007-0.008 mm in size and 0.0025 mm in width. There are a lot of them - the red blood cells of one person would cover an area of ​​2500 square meters.

    Hemoglobin

    Hemoglobin is a red blood pigment found in red blood cells. The main function of this protein substance is the transport of oxygen and partially carbon dioxide. In addition, antigens - blood group markers - are located on the membranes of red blood cells. Hemoglobin consists of two parts: a large protein molecule - globin and a non-protein structure built into it - heme, in the core of which there is an iron ion. In the lungs, iron combines with oxygen, and it is the combination of oxygen with iron that colors the blood red. The combination of hemoglobin with oxygen is unstable. When it breaks down, hemoglobin and free oxygen are again formed, which enters the tissue cells. During this process, the color of hemoglobin changes: arterial (oxygenated) blood is bright red, and “used” venous (carbon dioxide saturated) blood is dark red.

    How and where are these cells produced?

    More than 200 billion new red blood cells are produced in the human body every day. Thus, more than 8 billion are produced per hour, 144 million per minute, and 2.4 million per second! All this enormous work is performed by bone marrow weighing about 1500 g, located in various bones. The formation of red blood cells occurs in the bone marrow of the cranial and pelvic bones, trunk bones, sternum, ribs, as well as in the bodies of the vertebral discs. Until the age of 30, these blood cells are also produced in the femur and humerus. Red bone marrow contains cells that constantly produce new red blood cells. As soon as they mature, they penetrate through the walls of the capillaries into the circulatory system.

    In the human body, the breakdown and excretion of red blood cells occurs as quickly as their formation. Cell breakdown occurs in the liver and spleen. After the breakdown of hemes, certain pigments remain, which are excreted through the kidneys, giving urine its characteristic color.