The state of plasma is almost unanimously recognized by the scientific community as the fourth state of aggregation. Around this state, a separate science was even formed that studies this phenomenon - plasma physics. The state of a plasma or an ionized gas is represented as a set of charged particles, the total charge of which in any volume of the system is equal to zero - a quasi-neutral gas.

There is also a gas-discharge plasma, which occurs during a gas discharge. When an electric current passes through a gas, the first ionizes the gas, the ionized particles of which are current carriers. So in laboratory conditions, plasma is obtained, the degree of ionization of which can be controlled by changing the current parameters. However, unlike high-temperature plasma, the gas-discharge plasma is heated by the current, and therefore quickly cools when interacting with uncharged particles of the surrounding gas.

Electric arc - ionized quasi-neutral gas

Properties and parameters of plasma

Unlike gas, matter in the plasma state has a very high electrical conductivity. And although the total electric charge of the plasma is usually zero, it is significantly affected by magnetic field, which is capable of causing the flow of jets of such matter and separating it into layers, as is observed on the Sun.

Spicules - streams of solar plasma

Another property that distinguishes a plasma from a gas is the collective interaction. If gas particles usually collide in pairs, occasionally only a collision of three particles is observed, then plasma particles, due to the presence of electromagnetic charges, interact simultaneously with several particles.

Depending on their parameters, plasma is divided into the following classes:

• By temperature: low temperature - less than a million kelvin, and high temperature - a million kelvin or more. One of the reasons for the existence of such a separation is that only high-temperature plasma is capable of participating in thermonuclear fusion.
• Balanced and unbalanced. A substance in the plasma state, whose electron temperature is much higher than the temperature of the ions, is called nonequilibrium. In the case when the temperature of electrons and ions is the same, one speaks of an equilibrium plasma.
• According to the degree of ionization: high-ionization and low-ionization plasma. The fact is that even an ionized gas, 1% of whose particles are ionized, exhibits some plasma properties. However, plasma is usually referred to as a fully ionized gas (100%). An example of matter in this state is the solar matter. The degree of ionization is directly dependent on temperature.

Application

Plasma has found the greatest application in lighting engineering: in gas-discharge lamps, screens and various gas-discharge devices, such as a voltage stabilizer or a generator of microwave (microwave) radiation. Returning to lighting - all gas discharge lamps are based on the flow of current through the gas, which causes the ionization of the latter. A plasma screen popular in technology is a set of gas-discharge chambers filled with highly ionized gas. The electrical discharge that occurs in this gas generates ultraviolet radiation, which is absorbed by the luminophor and further causes it to glow in the visible range.

The second field of application of plasma is astronautics, and more specifically, plasma engines. Such engines are powered by a gas, usually xenon, which is strongly ionized in a gas discharge chamber. As a result of this process, heavy xenon ions, which are also accelerated by a magnetic field, form a powerful stream that creates engine thrust.

The greatest hopes are placed on plasma as the "fuel" for a thermonuclear reactor. Wishing to repeat the processes of fusion of atomic nuclei occurring on the Sun, scientists are working on obtaining the energy of fusion from plasma. Inside such a reactor, a highly heated substance (deuterium, tritium, or even) is in a plasma state, and, due to its electromagnetic properties, is held by a magnetic field. The formation of heavier elements from the original plasma occurs with the release of energy.

Plasma accelerators are also used in high energy physics experiments.

Plasma in nature

The plasma state is the most common form of matter, accounting for about 99% of the mass of the entire universe. The substance of any star is a clot of high-temperature plasma. In addition to stars, there is also interstellar low-temperature plasma that fills outer space.

The most striking example is the Earth's ionosphere, which is a mixture of neutral gases (oxygen and nitrogen), as well as a highly ionized gas. The ionosphere is formed as a result of gas exposure to solar radiation. The interaction of cosmic radiation with the ionosphere leads to the aurora.

On Earth, plasma can be observed at the moment of a lightning strike. An electrical spark charge flowing through the atmosphere strongly ionizes the gas in its path, thereby forming a plasma. It should be noted that a “full-fledged” plasma, as a set of individual charged particles, is formed at temperatures above 8,000 degrees Celsius. For this reason, the assertion that fire (whose temperature does not exceed 4,000 degrees) is plasma is only a popular misconception.

The times when we associated plasma with something unreal, incomprehensible, fantastic, are long gone. Today, this concept is actively used. Plasma is used in industry. It is most widely used in lighting engineering. An example is gas-discharge lamps illuminating the streets. But it is also present in fluorescent lamps. It is also in electric welding. After all, the welding arc is a plasma generated by a plasma torch. Many other examples could be cited.

Plasma physics is an important branch of science. Therefore, it is worth understanding the basic concepts related to it. This is what our article is about.

Definition and types of plasma

What is given in physics is quite clear. Plasma is such a state of matter when the latter has a significant (commensurate with the total number of particles) number of charged particles (carriers) that can more or less freely move inside the substance. The following main types of plasma in physics can be distinguished. If the carriers belong to particles of the same type (and particles of the opposite sign of charge, neutralizing the system, do not have freedom of movement), it is called one-component. Otherwise, it is two- or multi-component.

Plasma Features

So, we have briefly characterized the concept of plasma. Physics is an exact science, so definitions are indispensable here. Let us now tell about the main features of this state of matter.

In physics, the following. First of all, in this state, under the influence of already small electromagnetic forces, the movement of carriers arises - a current that flows in this way until these forces disappear due to the screening of their sources. Therefore, the plasma eventually passes into a state where it is quasi-neutral. In other words, its volumes, larger than some microscopic value, have zero charge. The second feature of plasma is related to the long-range nature of the Coulomb and Ampère forces. It consists in the fact that motions in this state, as a rule, have a collective character, involving a large number of charged particles. These are the basic properties of plasma in physics. It would be good to remember them.

Both these features lead to the fact that plasma physics is unusually rich and diverse. Its most striking manifestation is the ease of occurrence of various kinds of instabilities. They are a major barrier to practical use plasma. Physics is a science that is constantly evolving. Therefore, it is hoped that over time these obstacles will be removed.

Plasma in liquids

Turning to specific examples of structures, we begin by considering plasma subsystems in condensed matter. Among liquids, one should first of all name - an example to which the plasma subsystem corresponds - a single-component plasma of electron carriers. Strictly speaking, the category of interest to us should also include electrolyte liquids in which there are carriers - ions of both signs. However, for various reasons, electrolytes are not included in this category. One of them is that there are no light, mobile carriers, such as electrons, in the electrolyte. Therefore, the plasma properties mentioned above are much less pronounced.

Plasma in crystals

Plasma in crystals has a special name - solid state plasma. In ionic crystals, although there are charges, they are motionless. Therefore, there is no plasma. In metals, it is the conductivities that make up a one-component plasma. Its charge is compensated by the charge of immobile (more precisely, unable to move long distances) ions.

Plasma in semiconductors

Considering the basics of plasma physics, it should be noted that the situation in semiconductors is more diverse. Let's briefly characterize it. A one-component plasma in these substances can arise if appropriate impurities are introduced into them. If impurities easily donate electrons (donors), then n-type carriers appear - electrons. If impurities, on the contrary, easily select electrons (acceptors), then p-type carriers appear - holes (empty places in the distribution of electrons), which behave like particles with a positive charge. A two-component plasma formed by electrons and holes arises in semiconductors in an even simpler way. For example, it appears under the action of light pumping, which throws electrons from the valence band into the conduction band. We note that under certain conditions, electrons and holes attracted to each other can form a bound state similar to a hydrogen atom - an exciton, and if the pumping is intense and the density of excitons is high, then they merge together and form a drop of electron-hole liquid. Sometimes such a state is considered a new state of matter.

Gas ionization

The examples given were for special occasions plasma state, and plasma in its pure form is called many factors. Many factors can lead to its ionization: electric field(gas discharge, thunderstorm), light flux (photoionization), fast particles (radiation from radioactive sources, cosmic rays, which were discovered by increasing the degree of ionization with height). However, the main factor is the heating of the gas (thermal ionization). In this case, the detachment of the electron from the last collision with another gas particle, which has sufficient kinetic energy due to high temperature.

High temperature and low temperature plasma

The physics of low-temperature plasma is something that we come into contact with almost every day. Flame, matter in a gas discharge and lightning, various types of cold space plasma (iono- and magnetospheres of planets and stars), working substance in various technical devices (MHD generators, burners, etc.) can serve as examples of such a state. Examples of high-temperature plasma are the matter of stars at all stages of their evolution, except early childhood and old age, working substance in facilities for controlled thermonuclear fusion (tokamaks, laser devices, beam devices, etc.).

Fourth state of matter

A century and a half ago, many physicists and chemists believed that matter consists only of molecules and atoms. They are combined in combinations either completely disordered or more or less ordered. It was believed that there are three phases - gaseous, liquid and solid. Substances accept them under the influence of external conditions.

However, at present we can say that there are 4 states of matter. It is plasma that can be considered new, the fourth. Its difference from the condensed (solid and liquid) states lies in the fact that, like a gas, it does not have not only shear elasticity, but also a fixed volume. On the other hand, a plasma has in common with a condensed state the presence of short-range order, i.e., the correlation of the positions and composition of particles adjacent to a given plasma charge. In this case, such a correlation is generated not by intermolecular, but by Coulomb forces: a given charge repels charges of the same name with itself and attracts opposite ones.

Plasma physics was briefly considered by us. This topic is quite voluminous, so we can only say that we have revealed its basics. Plasma physics certainly deserves further consideration.

One and the same substance in nature has the ability to radically vary its properties depending on temperature and pressure. An excellent example of this is water, which exists as solid ice, liquids and steam. These are three states of aggregation of a given substance, which has chemical formula H 2 O. Other substances in vivo able to change their characteristics in a similar way. But in addition to those listed, in nature there is another state of aggregation - plasma. It is quite rare in earthly conditions, endowed with special qualities.

Molecular structure

What do the 4 states of matter in which matter resides depend on? From the interaction of the elements of the atom and the molecules themselves, endowed with the properties of mutual repulsion and attraction. These forces are self-compensated in the solid state, where the atoms are geometrically correct, forming a crystal lattice. At the same time, a material object is able to retain both of the above-mentioned qualitative characteristics: volume and shape.

But as soon as the kinetic energy of the molecules increases, moving chaotically, they destroy the established order, turning into liquids. They have fluidity and are characterized by the absence of geometric parameters. But at the same time, this substance retains its ability not to change the total volume. In a gaseous state mutual attraction between molecules is completely absent, so the gas has no shape and has the possibility of unlimited expansion. But the concentration of the substance at the same time drops significantly. The molecules themselves do not change under normal conditions. This is the main feature of the first 3 of the 4 states of matter.

State transformation

The process of turning a solid into other forms can be carried out by gradually increasing the temperature and varying the pressure. In this case, the transitions will occur abruptly: the distance between molecules will noticeably increase, intermolecular bonds will be destroyed with a change in density, entropy, and the amount of free energy. It is also probable that a solid body will immediately transform into a gaseous form, bypassing intermediate stages. It is called sublimation. Such a process is quite possible under ordinary terrestrial conditions.

But when the temperature and pressure indicators reach a critical level, the internal energy of the substance is formed so much that the electrons, moving at a frantic speed, leave their intra-atomic orbits. In this case, positive and negative particles are formed, but their density in the resulting structure remains almost the same. Thus, plasma arises - an aggregate state of matter, which, in fact, is a gas, fully or partially ionized, the elements of which are endowed with the ability to interact with each other over long distances.

High-temperature plasma of space

Plasma, as a rule, is a neutral substance, although it consists of charged particles, because the positive and negative elements in it, being approximately equal in number, compensate each other. This state of aggregation under normal terrestrial conditions is less common than the others mentioned earlier. But despite this, most cosmic bodies consist of natural plasma.

An example of this is the Sun and other numerous stars of the Universe. There temperatures are fantastically high. Indeed, on the surface of the main luminary of our planetary system, they reach 5,500 ° C. This is more than fifty times higher than the parameters that are necessary for water to boil. In the center of the fire-breathing ball, the temperature is 15,000,000°C. It is not surprising that gases (mostly hydrogen) ionize there, reaching state of aggregation plasma.

Low temperature plasma in nature

The interstellar medium that fills the galactic space also consists of plasma. But it differs from its high-temperature variety described earlier. Such a substance consists of ionized matter arising from the radiation emitted by stars. This is a low temperature plasma. In the same way, the sun's rays, reaching the limits of the Earth, create the ionosphere and the radiation belt above it, consisting of plasma. The differences are only in the composition of the substance. Although all the elements presented in the periodic table can be in a similar state.

Plasma in the laboratory and its application

According to the laws, it is easily obtained in the conditions familiar to us. When conducting laboratory experiments, a capacitor, a diode and a resistance connected in series are sufficient. A similar circuit is connected to a current source for a second. And if you touch the wires to a metal surface, then the particles of it itself, as well as the molecules of vapor and air located near it, are ionized and find themselves in the aggregate state of the plasma. Similar properties of matter are used to create xenon and neon screens and welding machines.

Plasma and natural phenomena

Under natural conditions, plasma can be observed in the light of the Northern Lights and during thunderstorms in the form of ball lightning. Explanation to some natural phenomena, to which mystical properties were previously attributed, modern physics has now given. Plasma formed and glowing at the ends of high and sharp objects (masts, towers, huge trees) in a special state of the atmosphere, centuries ago it was taken by sailors as a messenger of good luck. That is why this phenomenon was called "Fires of St. Elmo."

Seeing a corona discharge in the form of luminous tassels or beams during a thunderstorm in a storm, travelers took this as a good omen, realizing that they had avoided danger. It is not surprising, because the objects rising above the water, suitable for the "signs of the saint", could talk about the approach of the ship to the shore or prophesy a meeting with other ships.

Non-equilibrium plasma

The above examples eloquently indicate that it is not necessary to heat the substance to fantastic temperatures in order to achieve the state of the plasma. For ionization, it is enough to use the strength of the electromagnetic field. At the same time, heavy constituent elements matter (ions) do not acquire significant energy, because the temperature during this process may well not exceed several tens of degrees Celsius. Under such conditions, light electrons, breaking away from the main atom, move much faster than more inert particles.

Such a cold plasma is called non-equilibrium. In addition to plasma TVs and neon lamps, it is also used in the purification of water and food, and is used for disinfection for medical purposes. In addition, cold plasma can help accelerate chemical reactions.

Principles of use

An excellent example of how artificially created plasma is used for the benefit of mankind is the manufacture of plasma monitors. The cells of such a screen are endowed with the ability to emit light. The panel is a kind of "sandwich" of glass sheets, close to each other. Between them are boxes with a mixture of inert gases. They can be neon, xenon, argon. And phosphors of blue, green, red color are applied to the inner surface of the cells.

Outside the cells, conductive electrodes are connected, between which a voltage is created. As a result, an electric field arises and, as a result, the gas molecules are ionized. The resulting plasma emits ultraviolet rays, which are absorbed by the phosphors. In view of this, the phenomenon of fluorescence occurs by means of the photons emitted in this case. at the expense complex connection rays in space there is a bright image of a wide variety of shades.

Plasma Horrors

This form of matter assumes a deadly form during nuclear explosion. Plasma in large volumes is formed during the course of this uncontrolled process with the release of a huge amount of various kinds energy. resulting from the launch of the detonator, breaks out and heats the surrounding air to gigantic temperatures in the first seconds. At this place arises a deadly fire ball growing at an impressive rate. The visible area of ​​the bright sphere is enlarged by ionized air. Clots, clubs and jets of explosion plasma form a shock wave.

At first, the luminous ball, advancing, instantly absorbs everything in its path. Not only human bones and tissues turn into dust, but also solid rocks, even the most durable artificial structures and objects are destroyed. Armored doors to safe shelters do not save, tanks and other military equipment are flattened.

Plasma in its properties resembles a gas in that it does not have certain shapes and volumes, as a result of which it is able to expand indefinitely. For this reason, many physicists are of the opinion that it should not be considered a separate state of aggregation. However, its significant differences from just hot gas are obvious. These include: the ability to conduct electric currents and exposure to magnetic fields, instability and the ability of composite particles to have different speeds and temperatures, while collectively interacting with each other.

Blood plasma: constituent elements (substances, proteins), functions in the body, use

Blood plasma is the first (liquid) component of the most valuable biological medium called blood. Blood plasma takes up to 60% of the total blood volume. The second part (40 - 45%) of the fluid circulating in the bloodstream is taken over by formed elements: erythrocytes, leukocytes, and platelets.

The composition of blood plasma is unique. What is not there? Various proteins, vitamins, hormones, enzymes - in general, everything that ensures the life of the human body every second.

Composition of blood plasma

A yellowish transparent liquid released during the formation of a convolution in a test tube - is it plasma? No - this blood serum, in which there is no coagulated protein (factor I), it went into a clot. However, if you take blood into a test tube with an anticoagulant, then it will not allow it (blood) to clot, and heavy shaped elements will sink to the bottom after a while, while on top there will also be a yellowish, but somewhat cloudy, unlike serum, liquid, here it is and eat blood plasma, the turbidity of which is given by the proteins contained in it, in particular, fibrinogen (FI).

The composition of blood plasma is striking in its diversity. In it, in addition to water, which is 90 - 93%, there are components of protein and non-protein nature (up to 10%):

plasma in the blood

• , which take on 7 - 8% of the total volume of the liquid part of the blood (1 liter of plasma contains from 65 to 85 grams of proteins, the norm of total protein in the blood in biochemical analysis: 65 - 85 g / l). The main plasma proteins are recognized (up to 50% of all proteins or 40 - 50 g / l), (≈ 2.7%) and fibrinogen;
• Other substances of protein nature (complement components, carbohydrate-protein complexes, etc.);
• Biologically active substances(enzymes, hematopoietic factors - hemocytokines, hormones, vitamins);
• Low molecular weight peptides are cytokines, which, in principle, are proteins, but with a low molecular weight, they are produced mainly by lymphocytes, although other blood cells are also involved in this. Despite their "small growth", cytokines are endowed with the most important functions, they carry out the interaction of the immune system with other systems when triggering the immune response;
• Carbohydrates that are involved in metabolic processes that constantly occur in a living organism;
• Products resulting from these metabolic processes, which will subsequently be removed by the kidneys (, etc.);
• In the blood plasma, the vast majority of the elements of the table of D. I. Mendeleev are collected. True, some representatives of inorganic nature (potassium, iodine, calcium, sulfur, etc.) in the form of circulating cations and anions are easy to count, others (vanadium, cobalt, germanium, titanium, arsenic, etc.) - due to the meager amount, calculated with difficulty. Meanwhile, the share of all chemical elements present in the plasma is from 0.85 to 0.9%.

Thus, plasma is a very complex colloidal system in which everything "floats" that is contained in the human and mammalian body and everything that is being prepared for removal from it.

Water is a source of H 2 O for all cells and tissues, being present in plasma in such significant quantities, it provides a normal level (BP), maintains a more or less constant volume of circulating blood (BCC).

Differing in amino acid residues, physicochemical properties and other characteristics, proteins form the basis of the body, providing it with life. By dividing plasma proteins into fractions, one can find out the content of individual proteins, in particular, albumins and globulins, in blood plasma. This is done for diagnostic purposes in laboratories, this is done on an industrial scale to obtain very valuable therapeutic drugs.

Among the mineral compounds, the largest share in the composition of blood plasma belongs to sodium and chlorine (Na and Cl). These two elements occupy ≈ 0.3% of the mineral composition of the plasma, that is, they are, as it were, the main ones, which is often used to replenish the volume of circulating blood (BCC) in case of blood loss. In such cases, an affordable and cheap drug is prepared and transfused - isotonic sodium chloride solution. At the same time, 0.9% NaCl solution is called physiological, which is not entirely true: the physiological solution should, in addition to sodium and chlorine, contain other macro- and microelements (correspond to the mineral composition of the plasma).

Video: what is blood plasma

The functions of blood plasma are provided by proteins

The functions of blood plasma are determined by its composition, mainly protein. This issue will be considered in more detail in the sections below, devoted to the main plasma proteins, but briefly note the most important tasks that this method solves. biological material, not prevent. So, the main functions of blood plasma:

1. Transport (albumin, globulins);
2. Detoxification (albumin);
3. Protective (globulins - immunoglobulins);
4. Coagulation (fibrinogen, globulins: alpha-1-globulin - prothrombin);
5. Regulatory and coordination (albumin, globulins);

This is briefly about the functional purpose of the fluid, which, as part of the blood, constantly moves through the blood vessels, ensuring the normal functioning of the body. But still, some of its components should have been given more attention, for example, what did the reader learn about blood plasma proteins, having received so little information? But it is they who, in the main, solve the listed tasks (functions of blood plasma).

blood plasma proteins

Of course, to give the fullest amount of information, affecting all the features of the proteins present in plasma, in a small article devoted to the liquid part of the blood, is probably difficult to do. Meanwhile, it is quite possible to acquaint the reader with the characteristics of the main proteins (albumins, globulins, fibrinogen - they are considered the main plasma proteins) and mention the properties of some other substances of a protein nature. Especially since (as mentioned above) they ensure the high-quality performance of their functional duties with this valuable liquid.

The main plasma proteins will be discussed somewhat below, however, I would like to present the reader with a table that shows which proteins represent the main blood proteins, as well as their main purpose.

Table 1. Major plasma proteins

Albumins

Albumins are simple proteins that, compared to other proteins:

albumin structure

• They show the highest stability in solutions, but at the same time they dissolve well in water;
• They tolerate sub-zero temperatures well, not being particularly damaged when re-freezing;
• Do not collapse when dried;
• Staying for 10 hours at a temperature that is quite high for other proteins (60ᵒС), they do not lose their properties.

The ability of these important proteins is due to the presence in the albumin molecule of a very large number of polar decaying side chains, which determines the main functional responsibilities of proteins - participation in metabolism and the implementation of an antitoxic effect. The functions of albumin in blood plasma can be represented as follows:

1. Participation in water metabolism (due to albumins, the required volume of fluid is maintained, since they provide up to 80% of the total colloid osmotic blood pressure);
2. Participation in the transportation of various products, and especially those that are difficult to dissolve in water, for example, fats and bile pigment - bilirubin (bilirubin, having contacted albumin molecules, becomes harmless to the body and in this state is transferred to the liver);
3. Interaction with macro- and microelements entering the plasma (calcium, magnesium, zinc, etc.), as well as with many drugs;
4. Binding of toxic products in tissues where these proteins freely penetrate;
5. Carbohydrate transfer;
6. Binding and transfer of free fatty acids - fatty acids (up to 80%), sent to the liver and other organs from fat depots and, conversely, fatty acids do not show aggression against red blood cells (erythrocytes) and hemolysis does not occur;
7. Protection against fatty hepatosis of hepatic parenchyma cells and degeneration (fatty) of other parenchymal organs, and, in addition, an obstacle to the formation of atherosclerotic plaques;
8. Regulation of the "behavior" of certain substances in the human body (since the activity of enzymes, hormones, antibacterial drugs in bound form falls, these proteins help direct their action in the right direction);
9. Ensuring optimal levels of cations and anions in plasma, protection against negative impact salts of heavy metals that accidentally enter the body (they are complexed with them using thiol groups), neutralization of harmful substances;
10. Catalysis of immunological reactions (antigen→antibody);
11. Maintaining a constant blood pH (the fourth component of the buffer system is plasma proteins);
12. Assistance in the "construction" of tissue proteins (albumins, together with other proteins, constitute a reserve of "building materials" for such an important matter).

Albumin is synthesized in the liver. Middle period the half-life of this protein is 2 - 2.5 weeks, although some "live" for a week, while others "work" up to 3 - 3.5 weeks. By fractionating proteins from the plasma of donors, a valuable therapeutic drug (5%, 10% and 20% solution) is obtained, which has a similar name. Albumin is the last fraction in the process, so its production requires considerable labor and material costs, hence the cost of the therapeutic agent.

Indications for the use of donor albumin are various (in most cases quite severe) conditions: a large, life-threatening blood loss, a drop in albumin levels and a decrease in colloid osmotic pressure due to various diseases.

Globulins

These proteins take up a smaller proportion compared to albumin, but quite tangible among other proteins. Under laboratory conditions, globulins are divided into five fractions: α-1, α-2, β-1, β-2 and γ-globulins. Under production conditions, to obtain preparations from fraction II + III, gamma globulins are isolated, which will subsequently be used to treat various diseases accompanied by a violation in the immune system.

variety of forms of plasma protein species

Unlike albumins, water is not suitable for dissolving globulins, since they do not dissolve in it, but neutral salts and weak bases are quite suitable for preparing a solution of this protein.

Globulins are very important plasma proteins, in most cases they are acute phase proteins. Despite the fact that their content is within 3% of all plasma proteins, they solve the most important tasks for the human body:

• Alpha globulins are involved in all inflammatory reactions (an increase in the α-fraction is noted in the biochemical blood test);
• Alpha and beta globulins, being part of lipoproteins, carry out transport functions (fats in the free state in plasma appear very rarely, except after an unhealthy fatty meal, and under normal conditions, cholesterol and other lipids are associated with globulins and form a water-soluble form , which is easily transported from one organ to another);
• α- and β-globulins are involved in cholesterol metabolism (see above), which determines their role in the development of atherosclerosis, so it is not surprising that in pathologies that occur with lipid accumulation, the values ​​of the beta fraction change upwards;
• Globulins (alpha-1 fraction) carry vitamin B12 and certain hormones;
• Alpha-2-globulin is part of haptoglobin, which is very actively involved in redox processes - this acute phase protein binds free hemoglobin and thus prevents the removal of iron from the body;
• Part of the beta-globulins, together with gamma-globulins, solves the problems of the body's immune defense, that is, they are immunoglobulins;
• Representatives of alpha, beta-1 and beta-2 fractions tolerate steroid hormones, vitamin A (carotene), iron (transferrin), copper (ceruloplasmin).

Obviously, within their group, globulins differ somewhat from each other (primarily in their functional purpose).

It should be noted that with age or with certain diseases, the liver may begin to produce not quite normal alpha and beta globulins, while altered spatial structure macromolecules of proteins in the best way affect the functional abilities of globulins.

Gamma globulins

Gamma globulins are blood plasma proteins with the lowest electrophoretic mobility; these proteins make up the bulk of natural and acquired (immune) antibodies (AT). Gamma globulins formed in the body after encountering a foreign antigen are called immunoglobulins (Ig). At present, with the advent of cytochemical methods in the laboratory service, it has become possible to study serum in order to determine immune proteins and their concentrations in it. Not all immunoglobulins, and there are 5 classes of them, have the same clinical significance, in addition, their plasma content depends on age and changes in different situations (inflammatory diseases, allergic reactions).

Table 2. Classes of immunoglobulins and their characteristics

Concentration of immunoglobulins different groups has noticeable fluctuations in children of younger and middle age categories (mainly due to class G immunoglobulins, where rather high rates are noted - up to 16 g / l). However, after about 10 years of age, when vaccinations are done and the main childhood infections are transferred, the content of Ig (including IgG) decreases and is set at the level of adults:

IgM - 0.55 - 3.5 g / l;

IgA - 0.7 - 3.15 g / l;

IgG - 0.7 - 3.5 g / l;

fibrinogen

The first coagulation factor (FI - fibrinogen), which, during the formation of a clot, passes into fibrin, which forms a convolution (the presence of fibrinogen in plasma distinguishes it from serum), in fact, refers to globulins.

Fibrinogen is readily precipitated with 5% ethanol, which is used in protein fractionation, as well as half-saturated sodium chloride solution, plasma treatment with ether, and refreezing. Fibrinogen is thermolabile and completely folds at a temperature of 56 degrees.

Without fibrinogen, fibrin is not formed, and bleeding does not stop without it. The transition of this protein and the formation of fibrin is carried out with the participation of thrombin (fibrinogen → intermediate product– fibrinogen B → platelet aggregation → fibrin). Initial stages coagulation factor polymerization can be reversed, however, under the influence of a fibrin-stabilizing enzyme (fibrinase), stabilization occurs and the course of the reverse reaction is excluded.

Participation in the blood coagulation reaction is the main functional purpose of fibrinogen, but it also has other useful properties, for example, in the course of performing its duties, it strengthens the vascular wall, makes a small “repair”, sticking to the endothelium and thereby closing small defects, which then things arise in the course of a person's life.

Plasma proteins as laboratory parameters

In laboratory conditions, to determine the concentration of plasma proteins, you can work with plasma (blood is taken into a test tube with an anticoagulant) or conduct a study of serum taken into a dry dish. Serum proteins are no different from plasma proteins, with the exception of fibrinogen, which, as you know, is absent in the blood serum and which, without an anticoagulant, goes to form a clot. Basic proteins change their digital values ​​in the blood during various pathological processes.

An increase in the concentration of albumin in serum (plasma) is the rarest phenomenon that occurs with dehydration or with excessive intake (intravenous administration) of high concentrations of albumin. Decreased albumin levels may indicate depletion of liver function, kidney problems, or disorders in the gastrointestinal tract.

An increase or decrease in protein fractions is characteristic of a number of pathological processes, for example, acute-phase proteins alpha-1- and alpha-2-globulins, increasing their values, may indicate an acute inflammatory process localized in the respiratory organs (bronchi, lungs), affecting excretory system(kidney) or heart muscle (myocardial infarction).

A special place in the diagnosis of various conditions is given to the fraction of gamma globulins (immunoglobulins). The detection of antibodies helps to recognize not only infection, but also to differentiate its stage. More detailed information about the change in the values ​​of various proteins (proteinogram), the reader can find in a separate one.

Deviations from the norm of fibrinogen manifest themselves as disturbances in the hemocoagulation system, therefore this protein is the most important laboratory indicator of blood coagulation abilities (coagulogram, hemostasiogram).

As for other proteins that are important for the human body, when examining serum, using certain techniques, you can find almost any that are of interest for diagnosing diseases. For example, by calculating the concentration (beta-globulin, acute phase protein) in the sample and considering it not only as a “vehicle” (although this is probably in the first place), the doctor will know the degree of protein binding of ferric iron released by red blood cells, because Fe 3+ , as you know, being present in the free state in the body, gives a pronounced toxic effect.

The study of serum in order to determine the content (acute phase protein, metal glycoprotein, copper carrier) helps to diagnose such a severe pathology as Konovalov-Wilson's disease (hepatocerebral degeneration).

Thus, by examining plasma (serum), it is possible to determine in it the content of both those proteins that are vital and those that appear in a blood test as an indicator of a pathological process (for example,).

Blood plasma is a remedy

The preparation of plasma as a therapeutic agent began in the 30s of the last century. Now native plasma, obtained by spontaneous sedimentation of formed elements within 2 days, has not been used for a long time. The obsolete ones were replaced by new methods of blood separation (centrifugation, plasmapheresis). Blood after preparation is subjected to centrifugation and divided into components (plasma + shaped elements). The liquid part of the blood obtained in this way is usually frozen (fresh frozen plasma) and, in order to avoid infection with hepatitis, in particular hepatitis C, which has a rather long incubation period, is sent for quarantine storage. Freezing this biological medium at ultra low temperatures ah allows you to store it for a year or more, then to use it for the preparation of preparations (cryoprecipitate, albumin, gamma globulin, fibrinogen, thrombin, etc.).

Currently, the liquid part of blood for transfusions is increasingly prepared by plasmapheresis, which is the safest for the health of donors. Formed elements after centrifugation are returned by intravenous injection, and proteins lost with plasma in the body of a person who has donated blood are quickly regenerated, come to a physiological norm, while not violating the functions of the body itself.

In addition to fresh frozen plasma transfused in many pathological conditions, immune plasma obtained after immunization of a donor with a specific vaccine, for example, staphylococcal toxoid, is used as a therapeutic agent. Such plasma, which has a high titer of anti-staphylococcal antibodies, is also used to prepare anti-staphylococcal gamma globulin (human anti-staphylococcal immunoglobulin) - the drug is quite expensive, since its production (protein fractionation) requires considerable labor and material costs. And the raw material for it is blood plasma immunized donors.

Anti-burn plasma is also a kind of immune environment. It has long been noted that the blood of people who have experienced such a horror first carries toxic properties, however, after a month, burn antitoxins (beta and gamma globulins) begin to be detected in it, which can help "friends in misfortune" in the acute period of burn disease.

Of course, obtaining such a therapeutic agent is accompanied by certain difficulties, despite the fact that during the recovery period the lost liquid part of the blood is replenished with donor plasma, since the body of burnt people experiences protein depletion. However donor must be an adult and otherwise healthy, and his plasma must have a certain antibody titer (at least 1:16). The immune activity of convalescent plasma persists for about two years, and one month after recovery, it can be taken from convalescent donors without compensation.

From the plasma of donor blood for people suffering from hemophilia or other clotting pathology, which is accompanied by a decrease in antihemophilic factor (FVIII), von Willebrand factor (VWF) and fibrinase (factor XIII, FXIII), a hemostatic agent called cryoprecipitate is prepared. Its active ingredient is clotting factor VIII.

Video: about the collection and use of blood plasma

Fractionation of plasma proteins on an industrial scale

Meanwhile, the use of whole plasma in modern conditions is by no means always justified. Moreover, both from a therapeutic and economic point of view. Each of the plasma proteins has its own unique physicochemical and biological properties. And thoughtlessly infusing such a valuable product to a person who needs a specific plasma protein, and not all plasma, makes no sense, besides, it is expensive in material terms. That is, the same dose of the liquid part of the blood, divided into components, can benefit several patients, and not one patient who needs a separate drug.

The industrial production of drugs was recognized in the world after the developments in this direction by scientists at Harvard University (1943). Plasma protein fractionation was based on the Kohn method, the essence of which is the precipitation of protein fractions by the gradual addition of ethyl alcohol (concentration at the first stage - 8%, at the final stage - 40%) at low temperatures (-3ºС - stage I, -5ºС - last) . Of course, the method has been modified several times, but now (in various modifications) it is used to obtain blood products throughout the planet. Here it is brief scheme:

• Protein is precipitated in the first step fibrinogen(precipitate I) - this product, after special processing, will go to the medical network under its own name or will be included in a set to stop bleeding, called "Fibrinostat");
• The second stage of the process is the supernatant II + III ( prothrombin, beta and gamma globulins) - this fraction will go to the production of a drug called normal human gamma globulin, or will be released as a remedy called antistaphylococcal gamma globulin. In any case, from the supernatant obtained in the second stage, it is possible to prepare a preparation containing a large amount of antimicrobial and antiviral antibodies;
• The third, fourth stages of the process are needed in order to get to the sediment V ( albumen+ admixture of globulins);
• 97 – 100% albumen it comes out only at the final stage, after which it will take a long time to work with albumin until it enters medical institutions (5, 10, 20% albumin).

But this is just a brief outline, such production actually takes a lot of time and requires the participation of numerous personnel of varying degrees of qualification. At all stages of the process, the future most valuable medicine is under the constant control of various laboratories (clinical, bacteriological, analytical), because all the parameters of the blood product at the outlet must strictly comply with all the characteristics of transfusion media.

Thus, plasma, in addition to the fact that it ensures the normal functioning of the body in the blood, can also be an important diagnostic criterion that shows the state of health, or it can save the lives of other people using their unique properties. And it's not all about blood plasma. We didn't give complete description to all its proteins, macro- and microelements, to thoroughly describe its functions, because all the answers to the remaining questions can be found on the pages of VesselInfo.

Human blood is represented by 2 components: a liquid base or plasma and cellular elements. What is plasma and what is its composition? What is the function of plasma? Let's take everything in order.

All about plasma

Plasma is a liquid formed by water and solids. It makes up the bulk of the blood - about 60%. Thanks to plasma, blood has a liquid state. Although according to physical indicators(by density) plasma is heavier than water.

Macroscopically, plasma is a transparent (sometimes turbid) homogeneous liquid of light yellow color. It collects in the upper section of the vessels when the formed elements settle. Histological analysis shows that plasma is the intercellular substance of the liquid part of the blood.

Cloudy plasma becomes after a person consumes fatty foods.

What is plasma made of?

The composition of the plasma is presented:

• water;
• Salts and organic matter.

• Proteins;
• Amino acids;
• glucose;
• Hormones;
• enzyme substances;
• Minerals (Na, Cl ions).

What percentage of plasma volume is protein?

This is the most numerous plasma component, it occupies 8% of the total plasma. Plasma contains protein of various fractions.

The main ones are:

• Albumins (5%);
• Globulins (3%);
• Fibrinogen (belongs to globulins, 0.4%).

Composition and tasks of non-protein compounds in plasma

Plasma contains:

• Organic compounds based on nitrogen. Representatives: uric acid, bilirubin, creatine. An increase in the amount of nitrogen signals the development of azotomy. This condition occurs due to problems with the excretion of metabolic products in the urine or due to the active destruction of the protein and the intake of a large amount of nitrogenous substances in the body. The latter case is typical for diabetes, starvation, burns.
• Organic compounds that do not contain nitrogen. This includes cholesterol, glucose, lactic acid. They are also accompanied by lipids. All these components must be monitored, as they are necessary to maintain a full life.
• Inorganic substances (Ca, Mg). Na and Cl ions are responsible for maintaining a constant pH in the blood. They also monitor osmotic pressure. Ca ions take part in muscle contraction and stimulate the sensitivity of nerve cells.

Albumen

Albumin in plasma is the main component (more than 50%). It has a low molecular weight. The place of formation of this protein is the liver.

Purpose of albumin:

• Carries fatty acids, bilirubin, drugs, hormones.
• Takes part in metabolism and protein formation.
• Reserves amino acids.
• Forms oncotic pressure.

By the amount of albumin, doctors judge the state of the liver. If the content of albumin in plasma is reduced, then this indicates the development of pathology. Low levels of this plasma protein in children increase the risk of developing jaundice.

Globulins

Globulins are represented by large molecular compounds. They are produced by the liver, spleen, thymus.

There are several types of globulins:

• α - globulins. They interact with thyroxine and bilirubin, binding them. Catalyze the formation of proteins. Responsible for the transport of hormones, vitamins, lipids.
• β - globulins. These proteins bind vitamins, Fe, cholesterol. Carry Fe, Zn cations, steroid hormones, sterols, phospholipids.
• γ - globulins. Antibodies or immunoglobulins bind histamine and take part in protective immune responses. They are produced by the liver, lymphatic tissue, bone marrow, and spleen.

There are 5 classes of γ - globulins:

• IgG(about 80% of all antibodies). It is characterized by high avidity (the ratio of antibody to antigen). Can cross the placental barrier.
• IgM- the first immunoglobulin that is formed in the unborn baby. The protein is highly avid. It is the first found in the blood after vaccination.
• IgA.
• IgD.
• IgE.

Fibrinogen is a soluble plasma protein. It is synthesized by the liver. Under the influence of thrombin, the protein is converted into fibrin, an insoluble form of fibrinogen. Thanks to fibrin, in places where the integrity of the vessels has been broken, a blood clot is formed.

Other proteins and functions

Minor fractions of plasma proteins after globulins and albumins:

• Prothrombin;
• Transferrin;
• immune proteins;
• C-reactive protein;
• thyroxine-binding globulin;
• Haptoglobin.

The tasks of these and other plasma proteins are reduced to:

• Maintaining homeostasis and aggregate state of blood;
• control of immune responses;
• transport of nutrients;
• Activation of the blood coagulation process.

Functions and tasks of plasma

Why does the human body need plasma?

Its functions are varied, but basically they come down to 3 main ones:

• Transportation of blood cells, nutrients.
• Communication between all body fluids that are located outside the circulatory system. This function is possible due to the ability of plasma to penetrate through the vascular walls.
• Ensuring hemostasis. It implies control over the fluid, which stops during bleeding and removes the formed blood clot.

The use of plasma in donation

Today, whole blood is not transfused: for therapeutic purposes, plasma and shaped components are isolated separately. In blood donation points, blood is most often donated for plasma.

How to get plasma?

Plasma is obtained from the blood by centrifugation. The method allows to separate plasma from cellular elements using a special apparatus without damaging them.. The blood cells are returned to the donor.

Plasma donation has a number of advantages over simple blood donation:

• The amount of blood loss is less, which means that less harm is also done to health.
• Blood for plasma can be donated again after 2 weeks.

There are restrictions on donating plasma. So, a donor can donate plasma no more than 12 times a year.

Plasma donation takes no more than 40 minutes.

Plasma is the source of such an important material as blood serum. Serum is the same plasma, but without fibrinogen, but with the same set of antibodies. They are the ones who fight pathogens of various diseases. Immunoglobulins contribute to the rapid development of passive immunity.

To obtain blood serum, sterile blood is placed in a thermostat for 1 hour. Next, the resulting blood clot is peeled from the walls of the test tube and determined in the refrigerator for 24 hours. The resulting liquid is added to a sterile vessel using a Pasteur pipette.

Blood pathologies affecting the nature of the plasma

In medicine, there are several diseases that can affect the composition of the plasma. All of them pose a threat to human health and life.

The main ones are:

• Hemophilia. This is a hereditary pathology when there is a lack of a protein that is responsible for clotting.
• Blood poisoning or sepsis. A phenomenon that occurs due to infection directly in the bloodstream.
• DIC syndrome. A pathological condition caused by shock, sepsis, severe injuries. It is characterized by disorders of blood clotting, which lead simultaneously to bleeding and the formation of blood clots in small vessels.
• Deep venous thrombosis. With the disease, the formation of blood clots in deep veins (mainly in the lower extremities) is observed.
• Hypercoagulability. Patients are diagnosed with excessively high blood clotting. The viscosity of the latter increases.

A plasma test or Wasserman reaction is a study that detects the presence of antibodies in plasma to pale treponema. Based on this reaction, syphilis is calculated, as well as the effectiveness of its treatment.

Plasma is a liquid with a complex composition that plays an important role in human life. It is responsible for immunity, blood clotting, homeostasis.

Video - Health Guide (Blood Plasma)