Erythrocytes their features. red blood cells

The erythrocyte, the structure and functions of which we will consider in our article, is the most important component of the blood. It is these cells that carry out gas exchange, providing respiration at the cellular and tissue level.

Erythrocyte: structure and functions

The circulatory system of humans and mammals is characterized by the most perfect structure compared to other organisms. It consists of a four-chambered heart and a closed system of blood vessels through which blood circulates continuously. This tissue consists of a liquid component - plasma, and a number of cells: erythrocytes, leukocytes and platelets. Every cell has a role to play. The structure of a human erythrocyte is determined by the functions performed. This concerns the size, shape and number of these blood cells.

Features of the structure of erythrocytes

Erythrocytes have the shape of a biconcave disc. They are not able to move independently in the bloodstream, like leukocytes. They reach the tissues and internal organs thanks to the work of the heart. Erythrocytes are prokaryotic cells. This means that they do not contain a decorated core. Otherwise, they could not carry oxygen and carbon dioxide. This function is performed due to the presence of a special substance inside the cells - hemoglobin, which also determines the red color of human blood.

The structure of hemoglobin

The structure and functions of erythrocytes are largely due to the characteristics of this particular substance. Hemoglobin has two components. This is an iron-containing component called heme, and a protein called globin. For the first time, the English biochemist Max Ferdinand Perutz managed to decipher the spatial structure of this chemical compound. For this discovery, he was awarded the Nobel Prize in 1962. Hemoglobin is a member of the group of chromoproteins. These include complex proteins consisting of a simple biopolymer and a prosthetic group. For hemoglobin, this group is heme. This group also includes plant chlorophyll, which ensures the flow of the process of photosynthesis.

How does gas exchange take place

In humans and other chordates, hemoglobin is located inside the red blood cells, while in invertebrates it is dissolved directly in the blood plasma. In any case, the chemical composition of this complex protein allows the formation of unstable compounds with oxygen and carbon dioxide. Oxygenated blood is called arterial blood. It is enriched with this gas in the lungs.

From the aorta, it goes to the arteries, and then to the capillaries. These smallest vessels are suitable for every cell of the body. Here, red blood cells give off oxygen and attach the main product of respiration - carbon dioxide. With the blood flow, which is already venous, they enter the lungs again. In these organs, gas exchange occurs in the smallest bubbles - alveoli. Here, hemoglobin removes carbon dioxide, which is removed from the body through exhalation, and the blood is again saturated with oxygen.

Such chemical reactions are due to the presence of ferrous iron in the heme. As a result of the connection and decomposition, oxy- and carbhemoglobin are sequentially formed. But the complex protein of erythrocytes can also form stable compounds. For example, incomplete combustion of fuel releases carbon monoxide, which forms carboxyhemoglobin with hemoglobin. This process leads to the death of red blood cells and poisoning of the body, which can lead to death.

What is anemia

Shortness of breath, noticeable weakness, tinnitus, noticeable pallor of the skin and mucous membranes may indicate an insufficient amount of hemoglobin in the blood. The norm of its content varies depending on the gender. In women, this figure is 120 - 140 g per 1000 ml of blood, and in men it reaches 180 g / l. The content of hemoglobin in the blood of newborns is the highest. It exceeds this figure in adults, reaching 210 g / l.

Lack of hemoglobin is a serious condition called anemia or anemia. It can be caused by a lack of vitamins and iron salts in foodstuffs, an addiction to alcohol, the effect of radiation pollution on the body and other negative environmental factors.

A decrease in the amount of hemoglobin may also be due to natural factors. For example, in women, anemia can be caused by the menstrual cycle or pregnancy. Subsequently, the amount of hemoglobin is normalized. A temporary decrease in this indicator is also observed in active donors who often donate blood. But an increased number of red blood cells is also quite dangerous and undesirable for the body. It leads to an increase in blood density and the formation of blood clots. Often an increase in this indicator is observed in people living in high mountainous areas.

It is possible to normalize the level of hemoglobin by eating foods containing iron. These include liver, tongue, meat of cattle, rabbit, fish, black and red caviar. Plant products also contain the necessary trace element, but the iron in them is much more difficult to digest. These include legumes, buckwheat, apples, molasses, red peppers and herbs.

Shape and size

The structure of blood erythrocytes is characterized primarily by their shape, which is quite unusual. It really resembles a disk concave on both sides. This form of red blood cells is not accidental. It increases the surface of red blood cells and ensures the most efficient penetration of oxygen into them. This unusual shape also contributes to an increase in the number of these cells. So, normally, 1 cubic mm of human blood contains about 5 million red blood cells, which also contributes to the best gas exchange.

The structure of frog erythrocytes

Scientists have long established that human red blood cells have structural features that provide the most efficient gas exchange. This applies to form, quantity, and internal content. This is especially evident when comparing the structure of human and frog erythrocytes. In the latter, red blood cells are oval in shape and contain a nucleus. This significantly reduces the content of respiratory pigments. Frog erythrocytes are much larger than human ones, and therefore their concentration is not so high. For comparison: if a person has more than 5 million of them in a cubic mm, then in amphibians this figure reaches 0.38.

Evolution of erythrocytes

The structure of human and frog erythrocytes allows us to draw conclusions about the evolutionary transformations of such structures. Respiratory pigments are also found in the simplest ciliates. In the blood of invertebrates, they are found directly in the plasma. But this significantly increases the density of the blood, which can lead to the formation of blood clots inside the vessels. Therefore, over time, evolutionary transformations went towards the appearance of specialized cells, the formation of their biconcave shape, the disappearance of the nucleus, a decrease in their size and an increase in concentration.

Ontogenesis of red blood cells

The erythrocyte, the structure of which has a number of characteristic features, remains viable for 120 days. This is followed by their destruction in the liver and spleen. The main hematopoietic organ in humans is the red bone marrow. It continuously produces new red blood cells from stem cells. Initially, they contain a nucleus, which, as it matures, is destroyed and replaced by hemoglobin.

Features of blood transfusion

In a person's life, there are often situations in which a blood transfusion is required. For a long time, such operations led to the death of patients, and the real reasons for this remained a mystery. Only at the beginning of the 20th century it was established that the erythrocyte was to blame. The structure of these cells determines the blood groups of a person. There are four of them in total, and they are distinguished according to the AB0 system.

Each of them is distinguished by a special type of protein substances contained in red blood cells. They are called agglutinogens. They are absent in people with the first blood group. From the second - they have agglutinogens A, from the third - B, from the fourth - AB. At the same time, agglutinin proteins are contained in the blood plasma: alpha, beta, or both at the same time. The combination of these substances determines the compatibility of blood groups. This means that the simultaneous presence of agglutinogen A and agglutinin alpha in the blood is impossible. In this case, red blood cells stick together, which can lead to the death of the body.

What is the Rh factor

The structure of a human erythrocyte determines the performance of another function - the determination of the Rh factor. This sign is also necessarily taken into account during blood transfusion. In Rh-positive people, a special protein is located on the erythrocyte membrane. The majority of such people in the world - more than 80%. Rh-negative people do not have this protein.

What is the danger of mixing blood with red blood cells of different types? During the pregnancy of an Rh-negative woman, fetal proteins can enter her bloodstream. In response, the mother's body will begin to produce protective antibodies that neutralize them. During this process, the RBCs of the Rh-positive fetus are destroyed. Modern medicine has created special drugs that prevent this conflict.

Erythrocytes are red blood cells whose main function is to carry oxygen from the lungs to cells and tissues and carbon dioxide in the opposite direction. This role is possible due to the biconcave shape, small size, high concentration and the presence of hemoglobin in the cell.

An erythrocyte is called capable of transporting oxygen to the tissues due to hemoglobin, and carbon dioxide to the lungs. This is a cell of simple structure, which is of great importance for the life of mammals and other animals. The erythrocyte is the most numerous organism: about a quarter of all body cells are red blood cells.

General patterns of erythrocyte existence

An erythrocyte is a cell that originated from a red germ of hematopoiesis. About 2.4 million of these cells are produced per day, they enter the bloodstream and begin to perform their functions. During the experiments, it was determined that in an adult, erythrocytes, the structure of which is significantly simplified compared to other cells of the body, live 100-120 days.

In all vertebrates (with rare exceptions), oxygen is transported from the respiratory organs to the tissues through the hemoglobin of erythrocytes. There are exceptions: all members of the white-blooded fish family exist without hemoglobin, although they can synthesize it. Since, at the temperature of their habitat, oxygen dissolves well in water and blood plasma, these fish do not need its more massive carriers, which are erythrocytes.

Erythrocytes of chordates

A cell such as an erythrocyte has a different structure depending on the class of chordates. For example, in fish, birds and amphibians, the morphology of these cells is similar. They differ only in size. The shape of red blood cells, volume, size, and the absence of some organelles distinguish mammalian cells from others found in other chordates. There is also a pattern: mammalian erythrocytes do not contain extra organelles and they are much smaller, although they have a large contact surface.

Considering the structure and the person, common features can be identified immediately. Both cells contain hemoglobin and are involved in oxygen transport. But human cells are smaller, they are oval and have two concave surfaces. The erythrocytes of a frog (as well as birds, fish and amphibians, except salamander) are spherical, they have a nucleus and cell organelles that can be activated when necessary.

In human erythrocytes, as in the red blood cells of higher mammals, there are no nuclei and organelles. The size of erythrocytes in a goat is 3-4 microns, in humans - 6.2-8.2 microns. In amphium, the cell size is 70 microns. Clearly, size is an important factor here. The human erythrocyte, although smaller, has a large surface due to two concavities.

The small size of the cells and their large number made it possible to greatly increase the ability of the blood to bind oxygen, which is now little dependent on external conditions. And such structural features of human erythrocytes are very important, because they allow you to feel comfortable in a certain habitat. This is a measure of adaptation to life on land, which began to develop even in amphibians and fish (unfortunately, not all fish in the process of evolution were able to populate the land), and reached its peak in higher mammals.

The structure of blood cells depends on the functions that are assigned to them. It is described from three angles:

1. Features of the external structure.
2. Component composition of the erythrocyte.
3. Internal morphology.

Outwardly, in profile, the erythrocyte looks like a biconcave disk, and in full face - like a round cell. The diameter is normally 6.2-8.2 microns.

More often in the blood serum there are cells with small differences in size. With a lack of iron, the run-up decreases, and anisocytosis is recognized in the blood smear (many cells with different sizes and diameters). With a deficiency of folic acid or vitamin B 12, the erythrocyte increases to a megaloblast. Its size is approximately 10-12 microns. The volume of a normal cell (normocyte) is 76-110 cubic meters. µm.

The structure of red blood cells in the blood is not the only feature of these cells. Much more important is their number. The small size allowed to increase their number and, consequently, the area of ​​the contact surface. Oxygen is more actively captured by human erythrocytes than frogs. And most easily it is given in tissues from human erythrocytes.

The quantity really matters. In particular, an adult has 4.5-5.5 million cells per cubic millimeter. A goat has about 13 million red blood cells per milliliter, while reptiles have only 0.5-1.6 million, and fish have 0.09-0.13 million per milliliter. In a newborn child, the number of red blood cells is about 6 million per milliliter, while in an elderly child it is less than 4 million per milliliter.

Functions of red blood cells

Red blood cells - erythrocytes, the number, structure, functions and developmental features of which are described in this publication, are very important for humans. They implement some very important features:

• transport oxygen to tissues;
• carry carbon dioxide from tissues to lungs
• bind toxic substances (glycated hemoglobin);
• participate in immune reactions (they are immune to viruses and, due to reactive oxygen species, can have a detrimental effect on blood infections);
• able to tolerate certain drugs;
• participate in the implementation of hemostasis.

Let us continue the consideration of such a cell as an erythrocyte, its structure is maximally optimized for the implementation of the above functions. It is as light and mobile as possible, has a large contact surface for gaseous diffusion and chemical reactions with hemoglobin, and also quickly divides and replenishes losses in peripheral blood. This is a highly specialized cell, the functions of which cannot yet be replaced.

erythrocyte membrane

A cell such as an erythrocyte has a very simple structure, which does not apply to its membrane. It is 3 layers. The mass fraction of the membrane is 10% of the cell. It contains 90% proteins and only 10% lipids. This makes erythrocytes special cells in the body, since in almost all other membranes, lipids predominate over proteins.

The volumetric shape of erythrocytes can change due to the fluidity of the cytoplasmic membrane. Outside the membrane itself is a layer of surface proteins with a large number of carbohydrate residues. These are glycopeptides, under which there is a bilayer of lipids, with their hydrophobic ends facing in and out of the erythrocyte. Under the membrane, on the inner surface, there is again a layer of proteins that do not have carbohydrate residues.

Receptor complexes of the erythrocyte

The function of the membrane is to ensure the deformability of the erythrocyte, which is necessary for capillary passage. At the same time, the structure of human erythrocytes provides additional opportunities - cellular interaction and electrolyte current. Proteins with carbohydrate residues are receptor molecules, thanks to which erythrocytes are not "hunted" by CD8 leukocytes and macrophages of the immune system.

Red blood cells exist thanks to receptors and are not destroyed by their own immunity. And when, due to repeated pushing through the capillaries or due to mechanical damage, erythrocytes lose some receptors, spleen macrophages "extract" them from the bloodstream and destroy them.

The internal structure of the erythrocyte

What is an erythrocyte? Its structure is no less interesting than its functions. This cell is similar to a bag of hemoglobin bounded by a membrane on which receptors are expressed: clusters of differentiation and various blood groups (according to Landsteiner, according to Rhesus, according to Duffy and others). But inside the cell is special and very different from other cells in the body.

The differences are as follows: erythrocytes in women and men do not contain a nucleus, they do not have ribosomes and an endoplasmic reticulum. All of these organelles were removed after filling with hemoglobin. Then the organelles turned out to be unnecessary, because a cell with a minimum size was required to push through the capillaries. Therefore, inside it contains only hemoglobin and some auxiliary proteins. Their role has not yet been clarified. But due to the lack of an endoplasmic reticulum, ribosomes and a nucleus, it has become light and compact, and most importantly, it can easily deform along with a fluid membrane. And these are the most important structural features of erythrocytes.

erythrocyte life cycle

The main features of erythrocytes are their short life. They cannot divide and synthesize protein due to the nucleus removed from the cell, and therefore structural damage to their cells accumulates. As a result, erythrocytes tend to age. However, the hemoglobin that is captured by splenic macrophages at the time of RBC death will always be sent to form new oxygen carriers.

The life cycle of an erythrocyte begins in the bone marrow. This organ is present in the lamellar substance: in the sternum, in the wings of the ilium, in the bones of the base of the skull, and also in the cavity of the femur. Here, a precursor of myelopoiesis with a code (CFU-GEMM) is formed from a blood stem cell under the action of cytokines. After division, she will give the ancestor of hematopoiesis, denoted by the code (BOE-E). From it, a precursor of erythropoiesis is formed, which is indicated by the code (CFU-E).

This same cell is called a colony-forming red blood cell. It is sensitive to erythropoietin, a hormonal substance secreted by the kidneys. An increase in the amount of erythropoietin (according to the principle of positive feedback in functional systems) accelerates the processes of division and production of red blood cells.

RBC formation

The sequence of cellular bone marrow transformations of CFU-E is as follows: an erythroblast is formed from it, and from it - a pronormocyte, giving rise to a basophilic normoblast. As the protein accumulates, it becomes a polychromatophilic normoblast and then an oxyphilic normoblast. After the nucleus is removed, it becomes a reticulocyte. The latter enters the bloodstream and differentiates (matures) to a normal erythrocyte.

Destruction of red blood cells

Approximately 100-125 days the cell circulates in the blood, constantly carries oxygen and removes metabolic products from tissues. It transports carbon dioxide bound to hemoglobin and sends it back to the lungs, filling its protein molecules with oxygen along the way. And as it gets damaged, it loses phosphatidylserine molecules and receptor molecules. Because of this, the erythrocyte falls "under the sight" of the macrophage and is destroyed by it. And the heme obtained from all the digested hemoglobin is sent again for the synthesis of new red blood cells.

Erythrocytes or red blood cells are one of the formed elements of blood that perform numerous functions that ensure the normal functioning of the body:

• nutritional function is to transport amino acids and lipids;
• protective - in binding with the help of antibodies of toxins;
• enzymatic is responsible for the transfer of various enzymes and hormones.

Erythrocytes are also involved in the regulation of acid-base balance and in maintaining blood isotonia.

However, the main job of red blood cells is to deliver oxygen to the tissues and carbon dioxide to the lungs. Therefore, quite often they are called "respiratory" cells.

Features of the structure of erythrocytes

The morphology of erythrocytes differs from the structure, shape and size of other cells. In order for erythrocytes to successfully cope with the gas transport function of blood, nature endowed them with the following distinctive features:

These features are measures of adaptation to life on land, which began to develop in amphibians and fish, and reached their maximum optimization in higher mammals and humans.

It is interesting! In humans, the total surface area of ​​all red blood cells in the blood is about 3,820 m2, which is 2,000 times more than the surface of the body.

RBC formation

The life of a single erythrocyte is relatively short - 100-120 days, and every day the human red bone marrow reproduces about 2.5 million of these cells.

The full development of red blood cells (erythropoiesis) begins at the 5th month of intrauterine development of the fetus. Up to this point, and in cases of oncological lesions of the main hematopoietic organ, erythrocytes are produced in the liver, spleen and thymus.

The development of red blood cells is very similar to the process of development of the person himself. The origin and "intrauterine development" of erythrocytes begins in the erythron - the red germ of the hematopoiesis of the red brain. It all starts with a pluripotent blood stem cell, which, changing 4 times, turns into an "embryo" - an erythroblast, and from that moment it is already possible to observe morphological changes in the structure and size.

erythroblast. This is a round, large cell ranging in size from 20 to 25 microns with a nucleus, which consists of 4 micronuclei and occupies almost 2/3 of the cell. The cytoplasm has a purple hue, which is clearly visible on the cut of flat "hematopoietic" human bones. In almost all cells, the so-called "ears" are visible, which are formed due to the protrusion of the cytoplasm.

Pronormocyte. The size of the pronormocytic cell is smaller than that of the erythroblast - already 10-20 microns, this is due to the disappearance of the nucleoli. The purple hue is starting to fade.

Basophilic normoblast. In almost the same cell size - 10-18 microns, the nucleus is still present. Chromantin, which gives the cell a light purple color, begins to gather into segments and the outwardly basophilic normoblast has a spotty color.

Polychromatic normoblast. The diameter of this cell is 9-12 microns. The nucleus begins to change destructively. There is a high concentration of hemoglobin.

Oxyphilic normoblast. The disappearing nucleus is displaced from the center of the cell to its periphery. The cell size continues to decrease - 7-10 microns. The cytoplasm becomes distinctly pink in color with small remnants of chromatin (Joli bodies). Before entering the bloodstream, normally, the oxyphilic normoblast must squeeze out or dissolve its nucleus with the help of special enzymes.

Reticulocyte. The color of the reticulocyte is no different from the mature form of the erythrocyte. The red color provides the combined effect of the yellow-greenish cytoplasm and the violet-blue reticulum. The diameter of the reticulocyte ranges from 9 to 11 microns.

Normocyte. This is the name of a mature form of erythrocyte with standard sizes, pinkish-red cytoplasm. The nucleus disappeared completely, and hemoglobin took its place. The process of increasing hemoglobin during the maturation of an erythrocyte occurs gradually, starting from the earliest forms, because it is quite toxic to the cell itself.

Another feature of erythrocytes, which causes a short lifespan - the absence of a nucleus does not allow them to divide and produce protein, and as a result, this leads to the accumulation of structural changes, rapid aging and death.

Degenerative forms of erythrocytes

With various blood diseases and other pathologies, qualitative and quantitative changes in the normal levels of normocytes and reticulocytes in the blood, hemoglobin levels, as well as degenerative changes in their size, shape and color are possible. Below we consider changes that affect the shape and size of erythrocytes - poikilocytosis, as well as the main pathological forms of erythrocytes and due to what diseases or conditions such changes occurred.

Name	Shape change	Pathologies
Spherocytes	Spherical shape of the usual size with no characteristic enlightenment in the center.	Hemolytic disease of the newborn (blood incompatibility according to the AB0 system), DIC syndrome, speticemia, autoimmune pathologies, extensive burns, vascular and valve implants, other types of anemia.
microspherocytes	Balls of small sizes from 4 to 6 microns.	Minkowski-Choffard disease (hereditary microspherocytosis).
Elliptocytes (ovalocytes)	Oval or elongated shapes due to membrane anomalies. There is no central illumination.	Hereditary ovalocytosis, thalassemia, cirrhosis of the liver, anemia: megablastic, iron deficiency, sickle cell.
Target erythrocytes (codocytes)	Flat cells resembling a target in color - pale at the edges and a bright spot of hemoglobin in the center. The area of ​​the cell is flattened and increased in size due to excess cholesterol.	Thalassemia, hemoglobinopathies, iron deficiency anemia, lead poisoning, liver disease (accompanied by obstructive jaundice), removal of the spleen.
Echinocytes	Spikes of the same size are at the same distance from each other. Looks like a sea urchin.	Uremia, stomach cancer, bleeding peptic ulcer complicated by bleeding, hereditary pathologies, lack of phosphates, magnesium, phosphoglycerol.
acanthocytes	Spur-like protrusions of various sizes and sizes. Sometimes they look like maple leaves.	Toxic hepatitis, cirrhosis, severe forms of spherocytosis, lipid metabolism disorders, splenectomy, with heparin therapy.
Sickle-shaped erythrocytes (drepanocytes)	Look like holly leaves or sickle. Membrane changes occur under the influence of an increased amount of a special form of hemoglobin-s.	Sickle cell anemia, hemoglobinopathies.
stomatocytes	Exceed the usual size and volume by 1/3. The central enlightenment is not round, but in the form of a strip. When deposited, they become like bowls.	Hereditary spherocytosis, and stomatocytosis, tumors of various etiologies, alcoholism, cirrhosis of the liver, cardiovascular pathology, taking certain medications.
Dacryocytes	They resemble a tear (drop) or a tadpole.	Myelofibrosis, myeloid metaplasia, tumor growth in granuloma, lymphoma and fibrosis, thalassemia, complicated iron deficiency, hepatitis (toxic).

Let's add information about sickle-shaped erythrocytes and echinocytes.

Sickle cell anemia is most common in areas where malaria is endemic. Patients with this anemia have an increased hereditary resistance to malaria infection, while sickle-shaped red blood cells are also not amenable to infection. It is not possible to accurately describe the symptoms of sickle anemia. Since sickle-shaped erythrocytes are characterized by increased fragility of the membranes, capillary blockages often occur due to this, leading to a wide variety of symptoms in terms of severity and nature of manifestations. However, the most typical are obstructive jaundice, black urine and frequent fainting.

A certain amount of echinocytes is always present in human blood. Aging and destruction of erythrocytes is accompanied by a decrease in ATP synthesis. It is this factor that becomes the main reason for the natural transformation of disc-shaped normocytes into cells with characteristic protrusions. Before dying, the erythrocyte goes through the next stage of transformation - first the 3rd class of echinocytes, and then the 2nd class of spheroechinocytes.

Red blood cells in the blood end up in the spleen and liver. Such valuable hemoglobin will break down into two components - heme and globin. Heme, in turn, is divided into bilirubin and iron ions. Bilirubin will be excreted from the human body, along with other toxic and non-toxic erythrocyte residues, through the gastrointestinal tract. But iron ions, as a building material, will be sent to the bone marrow for the synthesis of new hemoglobin and the birth of new red blood cells.

They are erythrocytes. The structure and functions of these red cells are extremely important for the very existence of the human body.

About the structure of erythrocytes

These cells have a somewhat unusual morphology. Their appearance most of all resembles a biconcave lens. Only as a result of a long evolution, erythrocytes were able to obtain a similar structure. Structure and function are closely related. The fact is that the biconcave shape has several justifications at once. First of all, it allows red blood cells to carry even more hemoglobin, which has a very positive effect on the amount of oxygen supplied to cells and tissues in the future. Another big advantage of the biconcave shape is the ability of red blood cells to pass through even the narrowest vessels. As a result, this significantly reduces the possibility of their thrombosis.

About the main function of red blood cells

Red blood cells have the ability to carry oxygen. This gas is simply necessary for every person. At the same time, its entry into cells should be practically uninterrupted. Supplying oxygen to the entire body is not an easy task. This requires the presence of a special carrier protein. It is hemoglobin. The structure of erythrocytes is such that each of them can carry from 270 to 400 million molecules on its surface.

Oxygen saturation occurs in the capillaries located in the cell tissue. This is where gas exchange takes place. In this case, the cells give off carbon dioxide, which the body does not need in excess.

The capillary network in the lungs is very extensive. At the same time, the movement of blood through it has a minimum speed. This is necessary in order to have the possibility of gas exchange, because otherwise most red blood cells will not have time to give off carbon dioxide and be saturated with oxygen.

About hemoglobin

Without this substance, the main function of red blood cells in the body would not be realized. The fact is that it is hemoglobin that is the main carrier of oxygen. This gas can also get to the cells with the plasma flow, but in this liquid it is in a very small amount.

The structure of hemoglobin is quite complex. It consists of 2 compounds at once - heme and globin. The heme structure contains iron. It is necessary for efficient oxygen binding. Moreover, it is this metal that gives the blood its characteristic red color.

Additional functions of erythrocytes in the blood

At present, it is reliably known that these cells carry out not only the transport of gases. They are also responsible for a lot of things and their functions are strongly connected. The fact is that these biconcave blood cells provide transportation of amino acids to all parts of the body. These substances are the building material for the further formation of protein molecules, which are needed everywhere. Only after its formation in sufficient quantity, the potential of the main function of human erythrocytes can be 100% revealed.

In addition to transportation, erythrocytes are also involved in protecting the body. The fact is that special molecules - antibodies - are located on their surface. They are able to bind toxins and destroy foreign substances. Here, the functions of erythrocytes and leukocytes are very similar, because white blood cells are the main factor in protecting the body from pathogenic microorganisms.

Among other things, red blood cells are also involved in the enzymatic activity of the body. The fact is that they carry a fairly large amount of these biologically active substances.

What function do erythrocytes perform, in addition to those indicated? Of course, rolling. The fact is that it is erythrocytes that secrete one of the blood coagulation factors. In the event that they could not realize this function, then even the slightest damage to the skin would become a serious threat to the human body.

Currently, one more function of erythrocytes in the blood is known. We are talking about participation in the removal of excess water along with steam. To do this, the fluid is delivered by red blood cells to the lungs. As a result, the body gets rid of excess fluid, which also allows you to maintain the level of blood pressure at a constant level.

Due to their plasticity, erythrocytes are able to regulate. The fact is that in small vessels it must be maintained at a lower level than in large ones. Due to the ability of erythrocytes to somewhat change their shape, their passage through the bloodstream becomes easier and faster.

Coordinated work of all blood cells

It should be noted that the functions of erythrocytes, leukocytes, and platelets largely overlap. This causes the harmonious fulfillment of all the tasks assigned to the blood. So, for example, the functions of erythrocytes, leukocytes have something in common in the field of protecting the body from everything foreign. Naturally, the main role here belongs to white blood cells, because they are responsible for the formation of stable immunity. As for erythrocytes, they act as carriers of antibodies. This feature is also quite important.

If we talk about the joint activity of red blood cells and platelets, then here we will naturally talk about coagulation. Platelets circulate freely in the blood in the amount of 150*10 9 to 400*10 9 . In case of damage to the wall of the blood vessel, these cells are sent to the site of injury. Thanks to them, the defect is closed and, at the same time, for coagulation, the presence of all conditions-factors in the blood is necessary. One of them is produced just by erythrocytes. Without its formation, the coagulation process simply will not start.

About violations of the activity of erythrocytes

Most often they occur when the number of these cells in the blood is markedly reduced. In the event that their number becomes less than 3.5 * 10 12 / l, then this is already considered a pathology. This is especially true for men. At the same time, a sufficient level of hemoglobin content is much more important for the implementation of the function of erythrocytes. This protein should be in the blood in an amount of 130 to 160 g/l for men and 120 to 150 g/l for women. If there is a decrease in this indicator, then this condition is called anemia. Its danger lies in the fact that tissues and organs receive an insufficient amount of oxygen. If we are talking about a slight decrease (up to 90-100 g / l), then it does not entail serious consequences. In the event that this indicator decreases even more, then the main function of red blood cells can suffer significantly. At the same time, an additional burden falls on the heart, as it tries to at least somewhat compensate for the lack of oxygen in tissues, increasing the frequency of its contractions and moving blood through the vessels faster.

When does hemoglobin decrease?

First of all, this occurs as a result of iron deficiency in the human body. This condition occurs when there is insufficient intake of this element with food, as well as during pregnancy, when the fetus takes it from the mother's blood. This condition is especially characteristic for women whose interval between two pregnancies was less than 2 years.

Quite often it is at a low level after bleeding. At the same time, the speed of its recovery will depend on the nature of the person’s nutrition, as well as the intake of certain iron-containing drugs.

What to do to improve the work of red blood cells?

Once it has become clear which red blood cells perform a function, questions immediately arise about how to improve their activity in order to provide the body with even more hemoglobin. Currently, there are several ways to achieve this goal.

Choosing the right place to stay

You can increase the number of red blood cells in the blood by visiting mountainous areas. Naturally, in a few days there will be no more red cells. For a normal positive effect, you need to stay here for at least a few weeks, and preferably months. The accelerated production of red blood cells at altitude is due to the fact that the air is rarefied there. This means that the concentration of oxygen in it is less. To ensure a full supply of this gas in conditions of its deficiency, new erythrocytes are formed at an accelerated pace. If you then return to your usual area, then the level of red blood cells after a while will become the same.

Pill to help red cells

There are also medical ways to increase the number of red blood cells. They are based on the use of drugs containing erythropoietin. This substance promotes the growth and development of red blood cells. As a result, they are produced in larger quantities. It is worth noting that it is undesirable for athletes to use such a substance, otherwise they will be convicted of doping.

About and proper nutrition

In the case when the hemoglobin level falls below 70 g/l, this becomes a serious problem. To improve the situation, a transfusion of red blood cells is performed. The process itself is not the most beneficial for the body, because even with the right selection of blood for the AB0 group and the Rh factor, it will still be a foreign material and cause a certain response.

Often low hemoglobin levels are due to low meat intake. The fact is that only from animal proteins you can get enough iron. This element from vegetable protein is absorbed much worse.

The site provides reference information for informational purposes only. Diagnosis and treatment of diseases should be carried out under the supervision of a specialist. All drugs have contraindications. Expert advice is required!

Blood is a liquid connective tissue that fills the entire human cardiovascular system. Its amount in the body of an adult reaches 5 liters. It consists of a liquid part called plasma and formed elements such as leukocytes, platelets and erythrocytes. In this article, we will talk specifically about erythrocytes, their structure, functions, method of formation, etc.

What are erythrocytes?

This term comes from two words erythos" and " kitos", which in Greek means " red" and " container, cage". Erythrocytes are red blood cells in the blood of humans, vertebrates, and some invertebrates, which are assigned very diverse very important functions.

Red cell formation

The formation of these cells is carried out in the red bone marrow. Initially, the process of proliferation occurs ( tissue growth by cell multiplication). Then from hematopoietic stem cells ( cells - progenitors of hematopoiesis) a megaloblast is formed ( large red body containing a nucleus and a large amount of hemoglobin), from which, in turn, erythroblast is formed ( nucleated cell), and then the normocyte ( normal sized body). As soon as the normocyte loses its nucleus, it immediately turns into a reticulocyte - the immediate precursor of red blood cells. The reticulocyte enters the bloodstream and transforms into an erythrocyte. It takes about 2-3 hours to transform it.

Structure

These blood cells are characterized by a biconcave shape and a red color due to the presence of a large amount of hemoglobin in the cell. It is hemoglobin that makes up the bulk of these cells. Their diameter varies from 7 to 8 microns, but the thickness reaches 2 - 2.5 microns. The nucleus in mature cells is absent, which significantly increases their surface. In addition, the absence of a core ensures rapid and uniform penetration of oxygen into the body. The life span of these cells is about 120 days. The total surface area of ​​human red blood cells exceeds 3,000 square meters. This surface is 1500 times larger than the surface of the entire human body. If you place all the red cells of a person in one row, then you can get a chain, the length of which will be about 150,000 km. The destruction of these bodies occurs mainly in the spleen and partly in the liver.

Functions

1. Nutritious: carry out the transfer of amino acids from the organs of the digestive system to the cells of the body;

2. Enzymatic: are carriers of various enzymes ( specific protein catalysts);
3. Respiratory: this function is carried out by hemoglobin, which is able to attach to itself and give off both oxygen and carbon dioxide;
4. Protective: bind toxins due to the presence of special substances of protein origin on their surface.

Terms used to describe these cells

• microcytosis- the average size of red blood cells is less than normal;
• macrocytosis- the average size of red blood cells is larger than normal;
• normocytosis– the average size of red blood cells is normal;
• Anisocytosis- the sizes of red blood cells differ significantly, some are too small, others are very large;
• Poikilocytosis- the shape of the cells varies from regular to oval, sickle-shaped;
• Normochromia- red blood cells are colored normally, which is a sign of a normal level of hemoglobin in them;
• hypochromia- red blood cells are stained weakly, which indicates that they have less than normal hemoglobin.

Settling rate (ESR)

Erythrocyte sedimentation rate or ESR is a fairly well-known indicator of laboratory diagnostics, which means the rate of separation of unclotting blood, which is placed in a special capillary. Blood is divided into 2 layers - lower and upper. The bottom layer consists of settled red blood cells, but the top layer is plasma. This indicator is usually measured in millimeters per hour. The ESR value directly depends on the gender of the patient. In a normal state, in men, this indicator ranges from 1 to 10 mm / hour, but in women - from 2 to 15 mm / hour.

With an increase in indicators, we are talking about violations of the body. There is an opinion that in most cases, ESR increases against the background of an increase in the ratio of large and small protein particles in the blood plasma. As soon as fungi, viruses or bacteria enter the body, the level of protective antibodies immediately increases, which leads to changes in the ratio of blood proteins. From this it follows that especially often ESR increases against the background of inflammatory processes such as inflammation of the joints, tonsillitis, pneumonia, etc. The higher this indicator, the more pronounced the inflammatory process. With a mild course of inflammation, the rate increases to 15 - 20 mm / h. If the inflammatory process is severe, then it jumps up to 60-80 mm/hour. If during the course of therapy the indicator begins to decrease, then the treatment was chosen correctly.

In addition to inflammatory diseases, an increase in ESR is also possible with some non-inflammatory ailments, namely:

• Malignant formations;
• Severe ailments of the liver and kidneys;
• Severe blood pathologies;
• Frequent blood transfusions;
• Vaccine therapy.

Often, the indicator rises during menstruation, as well as during pregnancy. The use of certain medications can also cause an increase in ESR.

Hemolysis - what is it?

Hemolysis is the process of destruction of the membrane of red blood cells, as a result of which hemoglobin is released into the plasma and the blood becomes transparent.

Modern experts distinguish the following types of hemolysis:
1. By the nature of the flow:

• Physiological: old and pathological forms of red cells are destroyed. The process of their destruction is noted in small vessels, macrophages ( cells of mesenchymal origin) bone marrow and spleen, as well as in liver cells;
• Pathological: against the background of a pathological condition, healthy young cells are destroyed.

2. By place of origin:

• Endogenous: hemolysis occurs inside the human body;
• Exogenous: hemolysis occurs outside the body ( e.g. in a vial of blood).

3. According to the mechanism of occurrence:

• Mechanical: observed with mechanical ruptures of the membrane ( for example, a vial of blood had to be shaken);
• Chemical: observed when erythrocytes are exposed to substances that tend to dissolve lipids ( fatty substances) membranes. These substances include ether, alkalis, acids, alcohols and chloroform;
• Biological: noted when exposed to biological factors ( poisons of insects, snakes, bacteria) or transfusion of incompatible blood;
• Temperature: at low temperatures, ice crystals form in red blood cells, which tend to break the cell membrane;
• Osmotic: occurs when red blood cells enter an environment with a lower osmotic value than that of blood ( thermodynamic) pressure. Under this pressure, the cells swell and burst.

erythrocytes in the blood

The total number of these cells in human blood is simply enormous. So, for example, if your weight is about 60 kg, then there are at least 25 trillion red blood cells in your blood. The figure is very large, so for practicality and convenience, experts do not calculate the total level of these cells, but their number in a small amount of blood, namely in its 1 cubic millimeter. It is important to note that the norms for the content of these cells are determined immediately by several factors - the age of the patient, his gender and place of residence.

Norm of content of red blood cells

To determine the level of these cells helps clinical ( general) blood analysis .

• In women - from 3.7 to 4.7 trillion in 1 liter;
• In men - from 4 to 5.1 trillion in 1 liter;
• In children over 13 years old - from 3.6 to 5.1 trillion per 1 liter;
• In children aged 1 to 12 years - from 3.5 to 4.7 trillion in 1 liter;
• In children at 1 year old - from 3.6 to 4.9 trillion in 1 liter;
• In children at six months - from 3.5 to 4.8 trillion per 1 liter;
• In children at 1 month - from 3.8 to 5.6 trillion in 1 liter;
• In children on the first day of their life - from 4.3 to 7.6 trillion in 1 liter.

The high level of cells in the blood of newborns is due to the fact that during intrauterine development, their body needs more red blood cells. Only in this way can the fetus receive the amount of oxygen it needs in conditions of its relatively low concentration in the mother's blood.

The level of erythrocytes in the blood of pregnant women

Most often, the number of these bodies decreases slightly during pregnancy, which is completely normal. Firstly, during the gestation of the fetus, a large amount of water is retained in the woman's body, which enters the bloodstream and dilutes it. In addition, the organisms of almost all expectant mothers do not receive enough iron, as a result of which the formation of these cells again decreases.

An increase in the level of red blood cells in the blood

A condition characterized by an increase in the level of red blood cells in the blood is called erythremia , erythrocytosis or polycythemia .

The most common causes of this condition are:

• Polycystic kidney disease ( a disease in which cysts appear and gradually increase in both kidneys);
• COPD (chronic obstructive pulmonary disease - bronchial asthma, pulmonary emphysema, chronic bronchitis);
• Pickwick's syndrome ( obesity, accompanied by pulmonary insufficiency and arterial hypertension, i.e. persistent increase in blood pressure);
• Hydronephrosis ( persistent progressive expansion of the renal pelvis and calyx against the background of a violation of the outflow of urine);
• A course of steroid therapy;
• Congenital or acquired myeloma ( bone marrow tumors). A physiological decrease in the level of these cells is possible between 17.00 and 7.00, after eating and when taking blood in the supine position. You can find out about other reasons for lowering the level of these cells by consulting a specialist.
  

  erythrocytes in urine

  Normally, there should be no red blood cells in the urine. Their presence is allowed in the form of single cells in the field of view of the microscope. Being in the urine sediment in very small quantities, they may indicate that a person was involved in sports or did hard physical work. In women, a small amount of them can be observed with gynecological ailments, as well as during menstruation.

  A significant increase in their level in the urine can be noticed immediately, since the urine in such cases acquires a brown or red tint. The most common cause of the appearance of these cells in the urine is considered to be diseases of the kidneys and urinary tract. These include various infections, pyelonephritis ( inflammation of the kidney tissue), glomerulonephritis ( kidney disease characterized by inflammation of the glomerulus, ie. olfactory glomerulus), nephrolithiasis, and adenoma ( benign tumor) of the prostate gland. It is also possible to identify these cells in the urine with intestinal tumors, various blood clotting disorders, heart failure, smallpox ( contagious viral pathology), malaria ( acute infectious disease) etc.

  Often, red blood cells appear in the urine and during therapy with certain medications such as urotropin. The fact of the presence of red blood cells in the urine should alert both the patient himself and his doctor. Such patients need a repeat urinalysis and a complete examination. A repeat urinalysis should be taken using a catheter. If the repeated analysis once again establishes the presence of numerous red cells in the urine, then the urinary system is already subjected to examination.