Oncotic pressure of blood plasma is equal. Osmotic and oncotic blood pressure
Dissolved in the liquid part of the blood minerals- salt. In mammals, their concentration is about 0.9%. They are in a dissociated state in the form of cations and anions. The content of these substances depends mainly osmotic pressure blood.
Osmotic pressure is the force that causes the movement of a solvent through a semi-permeable membrane of less concentrated solution into a more concentrated one. Tissue cells and the cells of the blood itself are surrounded by semi-permeable membranes through which water easily passes and solutes hardly pass. Therefore, a change in the osmotic pressure in the blood and tissues can lead to swelling of cells or loss of water. Even minor changes salt composition blood plasma is detrimental to many tissues, and above all to the cells of the blood itself. The osmotic pressure of the blood is kept at a relatively constant level due to the functioning of regulatory mechanisms. In the walls blood vessels, in tissues, in the department diencephalon- the hypothalamus has special receptors that respond to changes in osmotic pressure - osmoreceptors.
Irritation of osmoreceptors causes a reflex change in the activity of the excretory organs, and they remove excess water or salts that have entered the blood. Great importance in this respect has the skin, connective tissue which absorbs excess water from the blood or gives it to the blood with an increase in the osmotic pressure of the latter.
The value of osmotic pressure is usually determined by indirect methods. The most convenient and common cryoscopic method is when depression is found, or a decrease in the freezing point of blood. It is known that the freezing point of a solution is the lower, the greater the concentration of particles dissolved in it, that is, the greater its osmotic pressure. The freezing point of the blood of mammals is 0.56-0.58 °C lower than the freezing point of water, which corresponds to an osmotic pressure of 7.6 atm, or 768.2 kPa.
Plasma proteins also create a certain osmotic pressure. It is 1/220 of the total osmotic pressure of blood plasma and ranges from 3.325 to 3.99 kPa, or 0.03-0.04 atm, or 25-30 mm Hg. Art. The osmotic pressure of plasma proteins is called oncotic pressure. It is much less than the pressure created by salts dissolved in plasma, since proteins have a huge molecular weight, and, despite their greater content in blood plasma by weight than salts, the number of their gram molecules is relatively small, and besides, they are much less mobile than ions. And for the value of osmotic pressure, it is not the mass of dissolved particles that matters, but their number and mobility.
Oncotic pressure prevents excessive transfer of water from blood to tissues and promotes its reabsorption from tissue spaces, therefore, with a decrease in the amount of proteins in the blood plasma, tissue edema develops.
Human health and well-being depend on the balance of water and salts, as well as the normal blood supply to organs. Balanced normalized exchange of water from one body structure to another (osmosis) is the basis healthy lifestyle life, as well as a means of preventing a number of serious illnesses(obesity, vegetovascular dystonia, systolic hypertension, heart disease) and a weapon in the fight for beauty and youth.
It is very important to maintain the balance of water and salts in the human body.
Nutritionists and doctors talk a lot about control and maintenance of water balance, but they do not delve into the origins of the process, dependencies within the system, and the definition of structure and relationships. As a result, people remain illiterate in this matter.
The concept of osmotic and oncotic pressure
Osmosis is the process of fluid transfer from a solution with a lower concentration (hypotonic) to an adjacent solution with a higher concentration (hypertonic). Such a transition is possible only under appropriate conditions: when liquids are “neighbored” and when a transmissive (semi-permeable) partition is separated. At the same time, they exert a certain pressure on each other, which in medicine is commonly called osmotic.
AT human body each biological fluid is just such a solution (for example, lymph, tissue fluid). And cell walls are "barriers".
One of key indicators the state of the body, the content of salts and minerals in the blood is the osmotic pressure
The osmotic pressure of the blood is an important vital sign, reflecting its concentration constituent elements(salts and minerals, sugars, proteins). It is also a measurable value that determines the force with which water is redistributed to tissues and organs (or vice versa).
It is scientifically determined that this force corresponds to the pressure in saline. That's what doctors call chloride solution sodium with a concentration of 0.9%, one of the main functions of which is plasma replacement and hydration, which allows you to fight dehydration, exhaustion in case of large blood loss, and it also protects red blood cells from destruction when drugs are administered. That is, with respect to blood, it is isotonic (equal).
Oncotic blood pressure component(0.5%) osmosis, whose value (required for normal functioning organism) ranges from 0.03 atm to 0.04 atm. Reflects the force with which proteins (in particular, albumins) act on neighboring substances. Proteins are heavier, but their number and mobility are inferior to salt particles. Because the oncotic pressure is much less than the osmotic pressure, however, this does not reduce its importance, which is to maintain the transition of water and prevent reabsorption.
No less important is such an indicator as oncotic blood pressure.
The analysis of the plasma structure, reflected in the table, helps to present their relationship and the significance of each.
Regulatory and metabolic systems (urinary, lymphatic, respiratory, digestive) are responsible for maintaining a constant composition. But this process begins with signals given by the hypothalamus, which responds to stimulation of osmoreceptors ( nerve endings in blood vessel cells).
The level of this pressure directly depends on the work of the hypothalamus.
For proper functioning and viability of the body, blood pressure must correspond to cellular, tissue and lymphatic pressure. With the correct and well-coordinated work of the body systems, its value remains constant.
It can grow rapidly with physical activity but quickly recovers.
How is osmotic pressure measured and its importance
Osmotic pressure is measured in two ways. The choice is made depending on the situation.
Cryoscopic method
It is based on the dependence of the temperature at which the solution freezes (depression) on the concentration of substances in it. Saturated ones have lower depression than dilute ones. For human blood normal pressure(7.5 - 8 atm) this value ranges from -0.56 ° C to - 0.58 ° C.
In this case, blood pressure is measured special device- osmometer
Measurement with an osmometer
This is a special device, which consists of two vessels with a separating partition, which has a partial patency. Blood is placed in one of them, covered with a lid with a measuring scale, and a hypertonic, hypotonic or isotonic solution is placed in the other. The level of the water column in the tube is an indicator of the osmotic value.
For the life of an organism, the osmotic pressure of blood plasma is the foundation. It provides tissues with the necessary nutrients, monitors the healthy and proper functioning of systems, and determines the movement of water. In the case of its excess, erythrocytes increase, their membrane bursts (osmotic hemolysis), with a deficiency, the opposite process occurs - drying out. This process underlies the work of each level (cellular, molecular). All body cells are semi-permeable membranes. Fluctuations caused by incorrect circulation of water lead to swelling or dehydration of cells and, as a result, organs.
Oncotic pressure of blood plasma is irreplaceable in matters of treatment serious inflammation, infections, suppuration. Growing in the very place where the bacteria are located (due to the destruction of proteins and an increase in the number of particles), it provokes the expulsion of pus from the wound.
Remember that osmotic pressure affects the entire body as a whole.
Another important role is the influence on the functioning and life span of each cell. The proteins responsible for oncotic pressure are important for blood clotting and viscosity, maintaining the Ph-environment, and protecting red blood cells from sticking together. They also provide the synthesis and transport of nutrients.
What affects osmosis performance
Osmotic pressure indicators can change for various reasons:
- The concentration of non-electrolytes and electrolytes ( mineral salts) dissolved in plasma. This dependence is directly proportional. A high content of particles provokes an increase in pressure, as well as vice versa. Main component– ionized sodium chloride (60%). However, from chemical composition osmotic pressure is independent. The concentration of cations and anions of salts is normal - 0.9%.
- Quantity and mobility of particles (salts). An extracellular environment with an insufficient concentration will receive water, an environment with an excess concentration will give it away.
- Oncotic pressure of plasma and blood serum, playing leading role in the retention of water in blood vessels and capillaries. Responsible for the creation and distribution of all fluids. A decrease in its performance is visualized by edema. The specificity of functioning is due high content albumins (80%).
The osmotic pressure is influenced by the salt content in the blood plasma
- electrokinetic stability. It is determined by the electrokinetic potential of particles (proteins), which is expressed by their hydration and the ability to repel each other and slide in solution conditions.
- Suspension stability, directly related to electrokinetic. Reflects the speed of connection of erythrocytes, that is, blood clotting.
- The ability of plasma components, when moving, to resist the flow (viscosity). With ductility, the pressure rises, with fluidity, it decreases.
- At physical work osmotic pressure increases. A value of 1.155% sodium chloride causes a feeling of fatigue.
- Hormonal background.
- Metabolism. An excess of metabolic products, "pollution" of the body provokes an increase in pressure.
Osmosis rates are influenced by human habits, food and drink consumption.
The metabolism in the human body also affects the pressure.
How nutrition affects osmotic pressure
Balanced proper nutrition- one of the ways to prevent jumps in indicators and their consequences. The following dietary habits negatively affect the osmotic and oncotic blood pressure:
Important! Better not to let critical condition, but regularly drink a glass of water and monitor the mode of its consumption and excretion from the body.
About measurement features blood pressure You will be told in detail in this video:
Plasma osmolytes (osmotically active substances), i.e. electrolytes of low molecular weight (inorganic salts, ions) and high molecular weight substances (colloidal compounds, mainly proteins) determine the most important characteristics of blood - osmoticandoncoticpressure. In medical practice, these characteristics are important not only in relation to blood perse(for example, the idea of the isotonicity of solutions), but also for the real situation invivo(for example, to understand the mechanisms of water passage through the capillary wall between blood and interstitial fluid[in particular, the mechanisms of edema development] separated by the equivalent of a semi-permeable membrane - the capillary wall). In this context for clinical practice parameters such as efficienthydrostaticandcentralvenouspressure.
Osmoticpressure() - excess hydrostatic pressure on the solution, separated from the solvent (water) by a semi-permeable membrane, at which the diffusion of the solvent through the membrane stops (under conditions invivo it is the vascular wall). The osmotic pressure of the blood can be determined by the freezing point (i.e. cryoscopically) and is normally 7.5 atm (5800 mmHg, 770 kPa, 290 mosmol/kg of water).
Oncoticpressure(colloidal osmotic pressure - COD) - the pressure that occurs due to the retention of water in the vascular bed by blood plasma proteins. With a normal protein content in plasma (70 g / l), the plasma CODE is 25 mm Hg. (3.3 kPa), while the CODE of the intercellular fluid is much lower (5 mm Hg, or 0.7 kPa).
Effectivehydrostaticpressure- the difference between the hydrostatic pressure of the intercellular fluid (7 mm Hg) and the hydrostatic pressure of blood in microvessels. Normally, effective hydrostatic pressure is 36–38 mm Hg in the arterial part of microvessels, and 14–16 mm Hg in the venous part.
Centralvenouspressure- blood pressure inside the venous system (in the superior and inferior vena cava), normally ranging from 4 to 10 cm of water column. Central venous pressure decreases with a decrease in BCC and increases with heart failure and stagnation in the circulatory system.
The movement of water through the wall of a blood capillary is described by the relationship (Starling):
The equation24–3
where: V is the volume of liquid passing through the capillary wall in 1 min; Kf - filtration coefficient; P1 - hydrostatic pressure in the capillary; P2 - hydrostatic pressure in the interstitial fluid; P3 - oncotic pressure in plasma; P4 - oncotic pressure in the interstitial fluid.
Infusionsolutionsandedema
The concept of iso-, hyper- and hypo-osmotic solutions was introduced in chapter 3 (see the section "Transport of water and maintenance of cell volume"). Saline infusion solutions for intravenous administration must have the same osmotic pressure as the plasma, i.e. be isoosmotic (isotonic, for example, the so-called saline solution - 0.85% sodium chloride solution).
If the osmotic pressure of the injected (infusion) fluid is higher (hyperosmotic, or hypertonic solution), this leads to the release of water from the cells.
If the osmotic pressure of the injected (infusion) fluid is lower (hypoosmotic, or hypotonic solution), this leads to the entry of water into the cells, i.e. to their swelling (cellular edema)
Osmoticedema(accumulation of fluid in the intercellular space) develops with an increase in the osmotic pressure of the tissue fluid (for example, with the accumulation of tissue metabolism products, impaired salt excretion)
Oncoticedema(colloidal osmotic edema), i.e. an increase in the water content in the interstitial fluid is due to a decrease in blood oncotic pressure during hypoproteinemia (mainly due to hypoalbuminemia, since albumins provide up to 80% of plasma oncotic pressure).
It's blood pressure (25 - 30 mm Hg or 0.03 - 0.04 atm.) created by proteins. The exchange of water between the blood and the intercellular fluid depends on the level of this pressure. The oncotic pressure of blood plasma is due to all blood proteins, but the main contribution (by 80%) is made by albumins. Large protein molecules are not able to go beyond the blood vessels, and being hydrophilic, they retain water inside the vessels. Thanks to this, squirrels play important role in transcapillary exchange. Hypoproteinemia, which occurs, for example, as a result of starvation, is accompanied by tissue edema (transition of water into the intercellular space).
The total amount of proteins in plasma is 7-8% or 65-85 g/l.
Functions of blood proteins.
1. Nutritional function.
2 . transport function.
3 . Creation of oncotic pressure.
4 . buffer function– Due to the presence of alkaline and acidic amino acids in plasma proteins, proteins are involved in maintaining acid-base balance.
5 . Participation in the processes of hemostasis.
The coagulation process includes a whole chain of reactions in which a number of plasma proteins (fibrinogen, etc.) are involved.
6. Proteins together with erythrocytes determine blood viscosity - 4.0-5.0, which in turn affects the hydrostatic blood pressure, ESR, etc.
The plasma viscosity is 1.8 - 2.2 (1.8-2.5). It is due to the presence of proteins in the plasma. With abundant protein nutrition the viscosity of plasma and blood increases.
7. Proteins are important component protective function blood(especially γ- globulins). They provide humoral immunity being antibodies.
All plasma proteins are divided into 3 groups:
· albumins,
· globulins,
· fibrinogen.
Albumins (up to 50g/l). They are 4-5% of the plasma mass, i.e. near 60% of all plasma proteins are accounted for by them. They are the smallest molecular weight. Them molecular mass about 70,000 (66,000). Albumins determine the colloid-osmotic (oncotic) plasma pressure by 80%.
The total surface area of many small albumin molecules is very large and therefore they are particularly well suited to function as carriers. various substances. They tolerate: bilirubin, urobilin, salts heavy metals, fatty acid, medications(antibiotics, etc.). One albumin molecule can simultaneously bind 20-50 bilirubin molecules. Albumins are formed in the liver. At pathological conditions their content is reduced.
Rice. 1. Plasma proteins
Globulins(20-30g/l). Their number reaches 3% of the mass of plasma and 35-40% of total proteins, molecular weight up to 450,000.
Distinguish α 1, α 2, β and γ-globulins(Fig. 1).
In faction α 1 -globulins (4%) There are proteins whose prosthetic group is carbohydrates. These proteins are called glycoproteins. About 2/3 of all plasma glucose circulates as part of these proteins.
Fraction α 2 -globulins (8%) includes haptoglobins related to chemical structure to mucoproteins, and copper-binding protein - ceruloplasmin. Ceruloplasmin binds about 90% of all copper contained in plasma.
Other proteins in the α 2 -globulin fraction include thyroxin-binding protein, vitamin B 12-binding globulin, cortisol-binding globulin.
To β-globulins (12%) are the most important protein carriers of lipids and polysaccharides. Importance lipoproteins is that they keep water-insoluble fats and lipids in solution and thus ensure their transfer by blood. About 75% of all plasma lipids are part of lipoproteins.
β– globulins involved in the transport of phospholipids, cholesterol, steroid hormones, metal cations (iron, copper).
To the third group - γ-globulins (16%) are proteins with the lowest electrophoretic mobility. γ–g lobulins are involved in the formation antibodies, protect the body from the effects of viruses, bacteria, toxins.
In almost all diseases, especially inflammatory ones, the content γ-globulins increases in plasma. Faction Boost γ-globulins accompanied by a decrease in the albumin fraction. There is a decrease in the so-called albumin globulin index, which is normally 0.2/2.0.
To γ–g Lobulins also include blood antibodies ( α and β – agglutinins), which determine its belonging to a particular blood group.
Globulins are produced in the liver bone marrow, spleen, lymph nodes. The half-life of globulins is up to 5 days.
Fibrinogen (2-4 g/l). Its amount is 0.2 - 0.4% of the plasma mass, molecular weight 340,000.
It has the property of becoming insoluble, passing under the influence of the thrombin enzyme into a fibrous structure - fibrin, which causes blood clotting (coagulation).
Fibrinogen is produced in the liver. Plasma devoid of fibrinogen is called serum.
Physiology of erythrocytes.
red blood cells- red blood cells that do not contain a nucleus (Fig. 2).
In men, 1 μl of blood contains an average of 4.5-5.5 million (about 5.2 million erythrocytes or 5.2x10 12 / l). In women, there are fewer erythrocytes and does not exceed 4-5 million in 1 µl (about 4.7x10 12 / l).
Functions of erythrocytes:
1. Transport - the transfer of oxygen from the lungs to the tissues and carbon dioxide from tissues to the alveoli of the lungs. The ability to perform this function is associated with the structural features of the erythrocyte: it lacks a nucleus, 90% of its mass is hemoglobin, the remaining 10% are proteins, lipids, cholesterol, and mineral salts.
Rice. 2. Human erythrocytes (electron microscopy)
In addition to gases, erythrocytes carry amino acids, peptides, nucleotides to various organs and tissues.
2. Participation in immune reactions - agglutination, lysis, etc., which is associated with the presence in the erythrocyte membrane of a complex of specific compounds - antigens (agglutinogens).
3. Detoxifying function - the ability to adsorb toxic substances and inactivate them.
4. Participation in the stabilization of the acid-base state of the blood due to hemoglobin and the carbonic anhydrase enzyme.
5. Participation in the processes of blood coagulation due to the adsorption of the enzymes of these systems on the erythrocyte membrane.
properties of erythrocytes.
1. Plasticity (deformability) is the ability of erythrocytes to reversible deformation when passing through micropores and narrow convoluted capillaries with a diameter of up to 2.5-3 microns. This property is ensured due to the special shape of the erythrocyte - a biconcave disc.
2. Osmotic stability of erythrocytes. The osmotic pressure in erythrocytes is slightly higher than in plasma, which provides cell turgor. It is created by a higher intracellular concentration of proteins compared to blood plasma.
3. Aggregation of erythrocytes. When the movement of blood slows down and its viscosity increases, erythrocytes form aggregates or coin columns. Initially, aggregation is reversible, but with a longer blood flow disturbance, true aggregates are formed, which can lead to microthrombosis.
4. Erythrocytes are able to repel each other, which is associated with the structure of the erythrocyte membrane. Glycoproteins, which make up 52% of the membrane mass, contain sialic acid, which gives a negative charge to red blood cells.
Erythrocyte functions maximum 120 days, average 60-90 days. With aging, the ability of erythrocytes to deform decreases, and their transformation into spherocytes (having the shape of a ball) due to changes in the cytoskeleton leads to the fact that they cannot pass through capillaries up to 3 microns in diameter.
RBCs are destroyed within vessels (intravascular hemolysis) or taken up and destroyed by macrophages in the spleen, Kupffer cells of the liver, and bone marrow (intracellular hemolysis).
Erythropoiesis- the process of formation of red blood cells in the bone marrow. The first morphologically recognizable cell of the erythroid series, which is formed from CFU-E (the precursor of the erythroid series), is the proerythroblast, from which 16-32 mature erythroid cells are formed during 4-5 subsequent doublings and maturation.
1) 1 proerythroblast
2) 2 basophilic erythroblasts of the first order
3) 4 basophilic erythroblasts of the second order
4) 8 polychromatophilic erythroblasts of the first order
5) 16 polychromatophilic erythroblasts of the second order
6) 32 polychromatophilic normoblasts
7) 32 oxyphilic normoblasts - denucleation of normoblasts
8) 32 reticulocytes
9) 32 erythrocytes.
Erythropoiesis in the bone marrow takes 5 days.
In the bone marrow of humans and animals, erythropoiesis (from proerythroblast to reticulocyte) occurs in erythroblastic islets of the bone marrow, which normally contain up to 137 per 1 mg of bone marrow tissue. When erythropoiesis is inhibited, their number can decrease several times, and when stimulated, it can increase.
Reticulocytes enter the blood from the bone marrow, maturing into erythrocytes during the day. The number of reticulocytes is used to judge the erythrocyte production of the bone marrow and the intensity of erythropoiesis. In humans, their number ranges from 6 to 15 reticulocytes per 1000 RBCs.
During the day, 60-80 thousand red blood cells enter 1 μl of blood. In 1 minute, 160x10 6 erythrocytes are formed.
The humoral regulator of erythropoiesis is the hormone erythropoietin. The main source of it in humans are the kidneys, their peritubular cells. They form up to 85-90% of the hormone. The rest is produced in the liver, submandibular salivary gland.
Erythropoietin enhances the proliferation of all dividing erythroblasts and accelerates the synthesis of hemoglobin in all erythroid cells, in reticulocytes, "starts" in cells sensitive to it the synthesis of mRNA necessary for the formation of enzymes involved in the formation of heme and globin. The hormone also increases blood flow in the vessels surrounding erythropoietic tissue in the bone marrow and increases the release of reticulocytes from the sinusoids of the red bone marrow into the blood.
Physiology of leukocytes.
Leukocytes or white blood cells are blood cells various shapes and quantities containing kernels.
On average in an adult healthy person contained in the blood 4 - 9x10 9 /l leukocytes.
An increase in their amount in the blood is called leukocytosis, decrease - leukopenia.
Viscometer Hess.
In the clinic, rotational viscometers are more often used.
In them, the liquid is in the gap between two coaxial bodies, such as cylinders. One of the cylinders (rotor) rotates, while the other is stationary. Viscosity is measured by the angular velocity of the rotor, which creates a certain moment of force on a stationary cylinder, or by the moment of force acting on a stationary cylinder, at a given angular velocity of rotation of the rotor.
In rotational viscometers, it is possible to change the velocity gradient by setting different angular velocities of rotation of the rotor. This makes it possible to measure viscosity at different velocity gradients. , which varies for non-Newtonian fluids such as blood.
Blood temperature
It largely depends on the intensity of the metabolism of the organ from which the blood flows, and varies between 37-40 ° C. When the blood moves, not only does the temperature in the various vessels equalize to some extent, but conditions are also created for the release or preservation of heat in the body.
Osmotic called blood pressure , which causes the transition of the solvent (water) through a semi-permeable membrane from a less to a more concentrated solution.
In other words, the movement of the solvent is directed from lower to higher osmotic pressure. Compare with hydrostatic pressure: the movement of a fluid is directed from higher to lower pressure.
Note! You can't say "... pressure... is called force...» ++601[B67] ++.
The osmotic pressure of the blood is approximately 7.6 atm. or 5776 mm Hg. (7.6´760).
The osmotic pressure of blood depends mainly on the low molecular weight compounds dissolved in it, mainly salts. About 60% of this pressure is created by NaCl. Osmotic pressure in the blood, lymph, tissue fluid, tissues is approximately the same and is constant. Even in cases where a significant amount of water or salt enters the blood, the osmotic pressure does not undergo significant changes.
Oncotic pressure- part of the osmotic pressure due to proteins. 80% of oncotic pressure is created albumins .
Oncotic pressure does not exceed 30 mm Hg. Art., i.e. is 1/200 of the osmotic pressure.
Several indicators of osmotic pressure are used:
Pressure units atm. Or mmHg
Plasma osmotic activity[B68] is the concentration of kinetically (osmotically) active particles per unit volume. The most commonly used unit is milliosmol per liter - mosmol/l.
1 osmol = 6.23 ´ 1023 particles
Normal osmotic activity of plasma = 285-310 mosmol/l.
Mosmol = mmol
In practice, the concepts of osmolarity are often used - mmol / l and osmolality mmol / kg (liter and kg of solvent)
The greater the oncotic pressure, the more water is retained in the vascular bed and the less it passes into the tissues and vice versa. Oncotic pressure affects the formation of tissue fluid, lymph, urine and water absorption in the intestine. Therefore, blood-substituting solutions should contain colloidal substances capable of retaining water [++601++].
With a decrease in the concentration of protein in the plasma, edema develops, since water ceases to be retained in the vascular bed and passes into the tissues.
Oncotic pressure plays a more important role in the regulation of water metabolism than osmotic pressure. Why? After all, it is 200 times less than osmotic. The fact is that the gradient concentration of electrolytes (which determine the osmotic pressure) on both sides biological barriers
In clinical and scientific practice such concepts as isotonic, hypotonic and hypertonic solutions are widely used. Isotonic solutions have a total ion concentration not exceeding 285-310 mmol/l. It can be 0.85% solution sodium chloride(it is often referred to as a "physiological" solution, although this does not fully reflect the situation), 1.1% potassium chloride solution, 1.3% sodium bicarbonate solution, 5.5% glucose solution, etc. Hypotonic solutions have a lower concentration of ions - less than 285 mmol / l, and hypertonic solutions, on the contrary, have a higher concentration above 310 mmol / l.
Erythrocytes are known to isotonic solution do not change their volume, in hypertonic - reduce it, and in hypotonic - increase in proportion to the degree of hypotension, up to the rupture of the erythrocyte (hemolysis). The phenomenon of osmotic hemolysis of erythrocytes is used in clinical and scientific practice to determine the qualitative characteristics of erythrocytes (a method for determining the osmotic resistance of erythrocytes).
