Rheological properties of blood

1. Rheologicalpropertiesofblood

2. Rheology • (fromGreek. ρέω-leakage and λογος-teaching) -the science of fluidity and deformation of continuous media (eg, conventional viscous liquids and liquids anomalous viscosity mountain rocks, suspensions, hydraulic mixtures, etc.).

3. Rheology • The term "rheology" introduced American scientist Eugene Bingham, which are important research rheological fluids and disperse systems. Officially, the term "rheology" adopted at the 3rd Symposium on Plasticity (1929, USA), however, certain provisions of rheology as a science were established long before.

4. Factors determining the rheological features of blood: 1. For Plasma: • viscosity, • chemical composition, • size pH. 2. For red blood cells: • the ability to deform, • aggregation, • and others.

5. Physico-chemical properties of blood • Blood density (specific gravity) in adults is 1,055-1,060 g/cm3, and plasma - 1,025-1,034 g/cm3. • The viscosity of the blood (plasma) is determined by the resistance that occurs when moving layers of blood. It is compared with the viscosity of water. Therefore, in adult blood viscosity at 5, 1.5-1.7 in plasma. • The viscosity depends on the concentration of plasma proteins. By increasing the protein concentration is increased. • Newborn blood viscosity greater than in adults.

6. The viscosity of the blood • It is the friction that occurs between layers of fluid moving at different speeds. As in the bloodstream at different rates move blood cells and plasma, the viscosity just depends on them. Determine the figure using viscometer. Normally, blood viscosity is about 5 (as the viscosity of water is 1).

7. Osmotic pressure • Osmotic pressure is determined by the concentration of salts. It helps to maintain the concentration of various substances at some level. • Solutions with osmotic pressure greater than the osmotic pressure in the cell - called hypertonic. • Solutions with lower pressure than the osmotic pressure in the cell - called hypotonic. • Solutions with osmotic pressure equal to the osmotic pressure in the cell is isotonic. • The osmotic pressure of blood is 285-310 mOsm/l.

8. Osmotic resistance of erythrocytes • The minimum osmotic resistance of erythrocytes observed in fresh blood 0,50-0,45% NaCl, maximum - to 0,34-0,32% NaCl.

9. Osmotic pressure • Maintaining osmotic pressure at a certain level is due to redistribution of ions between plasma and erythrocytes, and the ability of proteins to bind and give ions • In the walls of blood vessels, tissue, hypothalamus are osmoreceptors that are generated by changing the osmotic pressure. This leads to changes of the excretory organs.

10. Oncotic pressure • Oncotic pressure created by proteins and is an average of 30 mercury or 4 kPa. It helps to move water from the tissues into the bloodstream and hold it there. This counteracts the hydrostatic pressure of the blood-pressure, under which there is blood in the capillaries

11. Deformation capacity of red blood cells • It is an important indicator of the ability of red blood cells pass through the microcirculatory channel is the ability to deform, which is defined first, the properties of the membrane, and secondly erythrocyte content

12. Erythrocyte deformation capacity • Erythrocyte membranes up to 3% of the mass of the cell. Like other membrane is a lipid bilayer. Membrane proteins form a frame as they have the ability to return to its original erythrocyte shape after deformation.

13. Erythrocyte deformation capacity • Exercise control over the shape and the ability to be deformed proteins such as spektrin other proteins. Save some of erythrocyte requires energy consumption in the form of ATP, which is to maintain the proper structure of proteins and their interactions with other membrane components (eg spektrin).

14. Erythrocyte deformation capacity • However, the flexibility of erythrocyte membranes and caused by the presence in it of lipid bilayer. From the structure of the latter is connected rotation of the membrane around the cytoplasm. This rotation facilitates the passage of the erythrocyte through capillaries whose diameter is smaller than the diameter of the red blood cells.

15. Erythrocyte deformation capacity • Ability to deformation is directly dependent on the ratio of cholesterol / phospholipids. Increased cholesterol decreases the rate of diffusion of oxygen from red blood cells in the tissue.

16. Erythrocyte content • Regarding erythrocyte content, you should indicate that it is a solution of hemoglobin. Viscosity of content 5 times higher than the viscosity of blood plasma. Viscosity of the internal environment of erythrocytes depends on the conformation of the molecules of hemoglobin. Since the transition of hemoglobin in oxyhemoglobin internal viscosity increases 4 times. This leads to a deterioration in the ability of erythrocytes to deformation.

17. Erythrocyte content • Hemoglobin concentration also affects the ability of erythrocytes to deformation, namely an increase in hemoglobin concentration leads to a deterioration of deformation. This is because the hemoglobin can interact with the membrane and thereby determines the rigidity of the membrane.

18. Metabolism in the erythrocyte • The intensity of erythrocyte metabolism also affects the ability of erythrocytes to deformation. Increased rigidity of erythrocytes observed at lower content of ATP and 2,3-dyphosfohlitserat and vice versa.

19. Aggregation of red blood cells • Aggregation (Latin aggregatio- cluster)is a cluster of cells the process . It can occur in physiological conditions . But this statement is a lot of different discussions. Normal physiological aggregation is characterized by the formation of inverse linear chains.

20. Aggregation of red blood cells is performed by forming bridges between cells. As we know all the cells carry on their surface negative charge, which determines the strength of the mutual repulsion. The density of negatively charged groups on the surface of red blood cells are normal such that forms a single electronegative " cloud ", which attracts from the environment positively charged, ions. As a result, the cell becomes surrounded by electric double layer. So , macromolecular compounds can be adsorbed on their ends adjacent erythrocytes , forming bridges. Adsorption is carried out by electrical interactions.

21. Hemolysis of red blood cells • Hemolysis of red blood cells, hemoglobin release process of red blood cells. Hemolysis is the destruction of red blood cells without membranes (due to increased permeability) and in the destruction of red cell membrane when the shadow formed erythrocytes. • Hemolysis occurs normally. This so-called physiological hemolysis, due to the natural aging of erythrocytes. Hemolysis as pathological announcements

22. Types of hemolysis of erythrocytes • Osmotic • Mechanical • Thermal • Biological • Chemical

23. Erythrocyte sedimentation rate (ESR) • Density or specific gravity of erythrocytes (1,098) is higher than plasma (1.027) and therefore in vitro with blood clot devoid of ability, they slowly settle to the bottom. Erythrocyte sedimentation rate in healthy • male is 2-10 mm per hour, • Female 2-15 mm per hour. • In newborns, it is only 1.2 mm per hour. Intensive physical work leads to decreased ESR. Pregnant sedimentation rate can reach 45 mm per hour.

24. Factors determining the ESR • 1. Erythrocyte : • a) the number of red blood cells : a decrease in the number of erythrocytes sedimentation rate increases and vice versa (for example, infants, men and women); • b) the size of red blood cells : increased volume leads to an increase in ESR and vice versa; • c) saturation of hemoglobin in red blood cells : red blood cells Hypochromic slowly settle and vice versa; • d) the electric charge of erythrocytes : reducing the negative charge leads to an increase in ESR.

25. Factors determining the ESR Plasma ( increased ESR ): • a) an increase in globulin, especially - γ- globulin ; • b) an increase in fibrinogen ; • c) an increase in cholesterol; • d) change in pH to the alkaline side .

26. The destruction of red blood cells and hemoglobin Destruction of red blood cells may be: • 1. intravascular using blood phagocytes. Normally, it is destroyed by about 10% red blood cells. • 2. intracellular (in the spleen, liver and bone marrow).

27. The destruction of red blood cells • With the destruction of red blood cells destruction is the main product • verdohlobin → biliverdyn → indirect bilirubin, besides Fe and CO. • With the blood of indirect biolirubin goes to liver. In hepatocytes it is converted into direct bilirubin from the use glyukoronov acid.

28. Destruction of red blood cells

29. The process of converting indirect bilirubin into direct installed only in the postnatal period. Indirect bilirubin in the fetus through the placenta released without turning into a straight line. Due to the underdeveloped system of converting indirect bilirubin into direct novonarodzhenyhv blood accumulates in indirect bilirubin and there is physiological jaundice. • Direct bilirubin is secreted from liver cells via the bile passages in the bile.

30. The destruction of hemoglobin

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