Blood circulates in a closed vascular network, so its volume must correspond to the volume of the vascular bed. Total body blood volume is a species characteristic and is usually expressed as a percentage of body weight. Magnitude average blood volume in horse 9.8%, large cattle 8.2%, small cattle - 8.2%, tallow pigs - 4.6%, meat pigs - 7%, chickens - 8.5%, rabbits - 5.4%, dogs - 6.8% , in a cat - 5%. In humans, blood volume makes up about 7% of body weight.
Blood volume in males due to the increased content of red blood cells, usually more than in females. With age, blood volume decreases and dehydration of the body occurs.
To determine the volume of blood, some harmless dye (for example, congorot) is injected into it. After the paint is distributed throughout all the vessels, take a portion of blood from a vein and determine the concentration of paint in it. Then the volume of blood in which this dye is distributed is calculated.
For the same purpose they use tagged atom method. Blood is taken from the animal, red blood cells are separated and incubated in a solution containing radioactive phosphorus. Red blood cells adsorb it from the solution and become “labeled.” They are reintroduced into the blood of the same animal and after some time the radioactivity of the blood is determined.
Of the total blood volume, approximately half circulates throughout the body. The remaining half is retained in the dilated capillaries of some organs and is called deposited. The organs in which blood is deposited are called blood depot. Such organs include, for example, the spleen. It contains up to 16% of all blood in its lacunae - processes of capillaries. This blood is practically excluded from the circulation and does not mix with the circulating blood. When the smooth muscles of the spleen contract, the lacunae are compressed and blood enters the general channel.
The liver, which includes up to 20% of the blood volume, acts as a blood depot due to the contraction of the sphincters of the hepatic veins, through which blood flows from the liver. As a result, more blood enters the liver than flows out. The capillaries of the liver dilate, the blood flow in it slows down. However, the blood deposited in the liver is not completely excluded from the bloodstream.
Subcutaneous tissue deposits up to 10% of the blood. There are anastomoses in the blood capillaries of the skin. Some of the capillaries expand, fill with blood, and blood flow occurs through shortened paths (shunts).
The lungs can also be classified as organs that store blood. The volume of the vascular bed of the lungs is not constant. It depends on the ventilation of the alveoli, the size blood pressure in them and blood vessels great circle blood circulation
Thus, the deposited blood is excluded from the bloodstream and generally does not mix with the circulating blood. Due to the absorption of water, the deposited blood is thicker and contains a greater number of formed elements.
Value of deposited blood is as follows. When the body is in a state of physiological rest, its organs and tissues do not need increased blood supply. In this case, the deposition of blood reduces the load on the heart, as a result of which it works at 1/5 - 1/6 of its capacity. If necessary, blood can quickly pass into the bloodstream, e.g. physical work, strong emotional experiences, inhaling air with increased content carbon dioxide - that is, in all cases where it is necessary to increase the delivery of oxygen and nutrients to organs.
IN mechanisms of blood redistribution between the deposited and circulating vegetative nervous system: sympathetic nerves cause an increase in the volume of circulating blood, and parasympathetic nerves cause the transfer of blood to the depot. When a large amount of adrenaline enters the blood, the blood leaves the depot.
In case of blood loss, volume blood is restored, first of all, due to the transition of tissue fluid into the blood, after which deposited blood enters the bloodstream. As a result, the plasma volume is restored much faster than the amount of formed elements.
When blood volume increases (for example, when a large amount of blood substitutes is administered or when drinking a large amount of water), some of the fluid is quickly excreted by the kidneys. Most of it passes into the tissues and is then gradually eliminated from the body. Thus, the volume of blood filling the vascular bed is restored.

They are derivatives of mesenchyme. Together with the organs of hematopoiesis and immunopoiesis, lymphoid formations associated with the structures of non-hematopoietic organs, they are connected genetically and functionally, ensuring the maintenance of a constant internal environment (homeostasis), internal respiration, trophism, regulation and integration of all body systems, excretion of waste and protection (phagocytosis , cellular and humoral immunity, thrombus formation).

Blood morphology

Blood consists of plasma (55-60%) and formed elements (40-45%).

Plasma is the liquid part of blood. It contains proteins (more than 100 varieties), fats, carbohydrates, salts, hormones, enzymes, antibodies, dissolved gases, etc. The dry remainder of plasma accounts for 7-10%, the rest is water (90-93%). The main component of the dry residue is proteins (6.5-8.5%). Its medium is slightly alkaline (pH 7.4). Plasma proteins are divided into 2 fractions: light fraction consists of albumin (60%) and heavy - globulins (40%).

Albumin is synthesized in the liver. They provide colloid-osmotic blood pressure, retain water in the bloodstream (with their deficiency - edema), perform a transport function, adsorbing a number of compounds.

Globulins have two origins. Some of them, γ-globulins (antibodies), are produced by B lymphocytes and plasma cells, while others, β-globulins, fibrinogen and prothrombin, are formed in the liver. β-globulins are capable of binding and transporting ions of Fe, Cu, Zn, etc., and fibrinogen and prothrombin are involved in thrombus formation.

Formed elements of blood. D. L. Romanovsky in 1891 proposed staining blood smears with a mixture of two dyes - eosin and azure-II, which made it possible to differentiate the formed elements of blood, which include erythrocytes, leukocytes, stem cells and blood platelets.

Red blood cells. In mammals these are nuclear-free cells; in birds, reptiles, amphibians and fish they contain nuclei. The sizes of erythrocytes have specific characteristics and in each specific case they are divided into normocytes, microcytes and macrocytes (the variety of erythrocyte sizes is called anisocytosis).

Normally, red blood cells have the shape of a biconcave disc (discocytes). However, with aging and various types pathological conditions they can change their shape, and therefore they distinguish: planicites - with a flat surface, stomatocytes - dome-shaped, spherocytes - spherical, echinocytes - spiny, etc.

– (the variety of forms of red blood cells is called poikilocytosis - Greek poikilis - varied).

Functions of red blood cells: transport of O2 and CO2 (respiratory), amino acids, antibodies, toxins, medicinal substances by adsorption. Respiratory function is associated with the ability of hemoglobin (Hb) to attach oxygen (O2) and carbon dioxide (CO2). However, Hb can form strong bonds with other chemical compounds:

Hb – deoxyhemoglobin,

НbО – oxyhemoglobin,

НbСО2 – carbhemoglobin,

HbCO – carboxyhemoglobin (CO - carbon monoxide, the bond strength with Hb is 300 times higher than with O2),

Hb + strong oxidizing agents (KMnO4; aniline, nitrobenzene, etc.) → HbOH – methemoglobin (in these cases Fe+2 → Fe+3, as a result of which the ability of Hb to add oxygen is lost).

Features of the structure of the erythrocyte plasmalemma. The plasmalemma of erythrocytes is a typical biological membrane consisting of a bilipid layer and proteins in combination with carbohydrates. The ratio of lipids and proteins in it is 1:1. Carbohydrates are part of the glycocalyx. On outer surface the membranes contain phospholipids, sialic acid, antigenic oligosaccharides, and adsorbed proteins. On the inner side there are glycolytic enzymes, Na+-ATPases and K+-ATPases, glycoproteins and cytoskeletal proteins.

The lipids in the outer layer of the plasma membrane include phosphatidylcholine and sphingomyelin, which contain choline, and the inner layer contains phosphatidylserine and phosphatidylethanolamine, which carry an amino group at the end of the molecule. WITH outside there are glycolipids (5%). Glycophorin is a transmembrane glycoprotein. Its 16 oligosaccharide chains are located in the glycocalyx. Among them, sialic acid provides a negative charge to the outer surface of the membrane of mature red blood cells. This allows mature cells to exit the red bone marrow. Antigenic properties are associated with glycophorins various groups blood.

The near-membrane protein spectrin is part of the cytoskeleton and is involved in maintaining the shape of the erythrocyte. Spectrin, together with another protein, actin, is linked by the band 4.1 protein into a “knot complex”, which is connected to the protein glycophorin. A change in the amount of spectrin leads to a change in the shape of the red blood cell (spherocytes).

The spectrin cytoskeleton is connected to the plasmalemma by another protein - ankyrin in the localization zone of the transmembrane protein band 3, which is involved in the exchange of O2 and CO2. It also forms hydrophilic “pores” - water ion channels.

Composition of the cytoplasm of erythrocytes: Water – 66%, hemoglobin – 33% (heme in it is 4%).

In various pathological conditions, red blood cells may undergo:

1. gluing, forming coin columns (due to the loss of charge providing surface tension);

2. hemolysis (when exposed to a hypotonic solution, other types of plasma, or snake venom, hemoglobin enters the plasma, while the membrane remains intact);

3. heeling - wrinkling (when exposed to hypertonic solution); from Greek srena – tenderloin;

Aging red blood cells are phagocytosed by macrophages. Life expectancy of red blood cells is 120 days

Leukocytes. Unlike red blood cells, which “work” directly in the blood, leukocytes “work” in the tissues of the body, migrating (by diapedesis) through the walls of capillaries. These are nucleated cells.

Leukocytes are classified into granular (granulocytes) and non-granular (agranulocytes).

Granulocytes. Granular leukocytes (granulocytes) received their name due to the ambiguity of the stainability of their granules with dyes at different pH values, and therefore basophilic, eosinophilic and neutrophilic granular leukocytes are distinguished.

Basophils – cells spherical, with a diameter of up to 10–12 microns. The nucleus has a lobed or bean-shaped shape (depending on the degree of maturity of the cells). Their basophilic cytoplasm contains fairly large granules that are stained with basic dyes. One of the features of the contents of basophil granules is their metachromatic staining with thiazine dyes (methylene blue, toluidine blue, etc., and instead of a blue color, the granules acquire a purple, pink or red color).

Basophil granules contain biologically active substances: proteoglycans, GAGs (including heparin), vasoactive histamine, neutral proteases, serotonin, peroxidases, acid phosphatase, serotonin (a pineal gland hormone that weakens or inhibits the secretion of gonadoliberins in the hypothalamus), histidine decarboxylase (an enzyme for the synthesis of histamine), etc.

Functions of basophils. Basophils can phagocytose bacteria, prevent blood clotting (heparin), promote vasodilation and increase the permeability of their walls (histamine), resulting in edema. They mediate inflammation, activate macrophages, and participate in immunological reactions of an allergic nature: they secrete eosinophilic chemotactic factor, which stimulates the migration of eosinophils. In asthma, anaphylaxis, and rash, an immediate type of degranulation is observed, the trigger of which is the IgE receptor for IgE. Together with mast cells, they participate in the anticoagulation system of the blood and the regulation of vascular wall permeability; together with neutrophils they form biologically active metabolites arachidonic acid– leukotrienes and prostaglandins. Basophilic granulocytes are not active inducers in the development of delayed-type hypersensitivity.

Basophils remain in the peripheral blood for approximately 1-2 days, and then migrate into the intercellular substance connective tissue, where their life expectancy is not long.

Eosinophils . The sizes of these cells reach 12-17 microns. The nucleus of mature cells usually contains 2 segments, but in sheep there are more. Band and young eosinophils are very rare. The granules in the cytoplasm are quite large. There are two types of them: primary azurophilic and secondary eosinophilic (modified lysosomes). The center of the eosinophilic granule contains a crystalloid, which contains the main basic protein, rich in arginine, cationic protein, lysosomal hydrolytic enzymes, peroxidase, histaminase, etc. The peroxidase activity of eosinophilic granulocytes is not associated with the presence of myeloperoxidase, which is strictly specific to the neutrophilic granulocyte system.

IN allergic reactions The Fc receptor of the plasmalemma for IgE, as well as C3 and C4 receptors, are involved.

Eosinophilic granulocytes remain in the blood for about 12 hours, and then migrate into the intercellular substance of the connective tissue, where they function for up to 8-12 days (there are 500 times more of them in the connective tissue than in the blood). The peroxidase activity of eosinophilic granulocytes is not associated with the presence of myeloperoxidase, which is strictly specific to the neutrophilic granulocyte system.

Neutrophils . The sizes of these cells vary between 9–12 µm. The shape of the nucleus is not constant and depends on the degree of maturity of the cells. In this regard, young, band and segmented neutrophil granulocytes are distinguished. In young neutrophils, the nucleus is bean-shaped, and there are relatively few granules in the cytoplasm. The nuclei of band neutrophils look like varying degrees a curved rod, and in mature cells it is fragmented into segments connected by thin bridges. The cytoplasm of neutrophils contains 2 types of granules:

1) primary azurophilic nonspecific (PAN), their size - 0.4-0.8 μm (up to 20%), are primary lysosomes containing ß-glucuronidase, acid ß-glycerophosphate dehydrogenase, acid protease, lysozyme (muramidase), acid phosphatase, myeloperoxidase (converts hydrogen peroxide into molecular oxygen).

2) secondary neutrophil specific granules (SNS), the size of which is 0.1-0.3 microns; they contain alkaline phosphatase, phagocytins, aminopeptidases, lysozyme, cationic proteins and the protein lactoferrin, which ensures the adhesion of bacteria (bacterial multiplication) and inhibition of the formation of leukocytes in the red bone marrow.

The description of neutrophil granulocytes should be supplemented with modern data on tertiary granules, secretory vesicles and adhesion molecules.

Neutrophil function– nonspecific antibacterial protection through phagocytosis and release of bactericidal substances, participation in inflammatory reactions (carried out outside the vessels, in the intercellular substance of connective tissues). Neutrophil granulocytes do not participate in the formation of endogenous pyrogen, which is now identified as interleukin-1; it is produced by cells of the monocyte-macrophage system. They remain in the blood for up to 8-12 hours, and in the tissues for up to 9 days, where they die.

Agranulocytes. Non-granular leukocytes include lymphocytes and monocytes. Both of these groups of cells take an active part in the body's immune reactions. Immunity is a way of protecting the body from living bodies and substances that carry signs of genetic foreignness.

Lymphocytes . By degree of maturity lymphocytes are divided into large (10 µm), medium ((7-10 µm) and small (4.5-6 µm). Small lymphocytes are mature. They contain a large round nucleus with a slight depression, occupying almost the entire cell. It is surrounded by a narrow a rim of basophilic cytoplasm. By origin and functional properties There are 4 main groups of lymphocytes: B lymphocytes, T lymphocytes, natural killer (NK) cells and K cells. They all participate in ensuring immune reactions, protection from everything foreign that comes from outside and is formed in the body itself.

B lymphocytes Formed in lymph nodes and carry out specific humoral immunity (supply antibodies to the blood, lymph and tissue fluid). On the surface of the plasma membrane of B lymphocytes there are antigen-specific receptors, which are antibodies - immunoglobulins (Ig) of classes M and D, or surface immunoglobulins (SIg). Antigens recognized by the receptors attach to them, as a result of which B lymphocytes are activated, proliferate repeatedly and differentiate into effector cells - plasmacytes, or antibody-forming cells (AFC), capable of producing antibodies (immunoglobulins). Antibodies on their surface have binding sites for this specific antigen.

The process of lymphocyte activation can be represented in the following sequence: Activated B lymphocyte → plasmablast (diameter up to 30 microns) → proplasmocyte → mature plasmacyte (diameter about 10 microns).

B lymphocytes live from several weeks to tens of months.

T lymphocytes, natural killer cells ( N.K. ) and K cells are formed in the thymus. They carry out specific cellular immune reactions and regulate humoral immunity. The plasmalemma of T lymphocytes contains surface antigenic markers (histocompatibility antigens) and many receptors with which they recognize foreign antigens and immune complexes. After meeting antigens, T-lymphocytes turn into T-effectors: T-killers, T-helpers and T-suppressors.

Effector cells of T-lymphocytes T-killer cells (cytotoxic) - provide cellular immunity. Possessing a cytotoxic effect, they interact with target cells due to direct contact with them or due to the short-acting toxic mediators they produce. As a result of this interaction, the permeability of the target cell membrane changes, which leads to its death.

When antigens act, T-lymphocytes produce special soluble substances, lymphokines, which transmit information about the antigens to B-lymphocytes.

T-helpers are assistants to B-lymphocytes, they recognize antigen and enhance the production of antibodies; Suppressor T cells, on the contrary, suppress the production of antibodies by B lymphocytes.

The lifespan of T-lymphocytes is up to 10 years.

Recently, scientific publications (G. M. Mogilnaya et al., 2002) indicate that it is necessary to introduce the classification of T-lymphocytes accepted by immunologists, which is based on the determination of surface differentiation antigens (cluster of differentiation - CD) using immunocytochemistry.

Two subpopulations of native T lymphocytes with the CD23 antigen leave the thymus. Helper T cells are labeled with the CD4 antigen, and killer T cells with CD8. It has been established that during the immune response, CD4+ T helper cells (ThO) give rise to two subpopulations of Th1 and Th2 helper cells with a predominance of one of them, depending on the intra- or extracellular localization of the pathogen, or on the characteristics of the antigen. Through the production of various sets of cytokines Th1 (interferon gama, tumor necrosis factor-alpha, lymphotoxin, interleukin-2) and Th2 (interleukins -4, -5, -6, -10, -13 and transforming growth factor - beta) regulate the development of the immune system inflammation. Hypersensitive T lymphocytes belong to the Th1 helper class, so they do not need to be isolated into a separate cell form. It is worth noting that after contact with the antigen and the synthesis of cytotoxins (perforin, granzymes), the CD8+ killer T cell is called a cytotoxic T lymphocyte (CTL).

During local contact of the CTL with the target cell, the release of cytotoxins is strictly directed into the zone of spatial connection between the T-cell receptor and the antigen. In addition, osmotic cell lysis is observed, due to the independent effect of perforin, which leads to the release and dispersion of the intracellularly localized pathogen. It is advisable to point out that the death of the target cell by apoptosis, which occurs under the combined influence of perforin and granzymes, is biologically expedient, since it leads to membrane isolation of the degraded pathogen or other antigen.

Memory T and B cells – lymphocytes returning to an inactive state, but having already acquired information (memory) from an encounter with a specific antigen. When they encounter this antigen again, they quickly provide an immune response of significant intensity.

T and B lymphocytes in the vascular bed are functionally relatively inactive. Their activation is carried out by antigens, as a result of which these cells turn into effector forms of cellular and humoral immunity, due to which the fund of memory cells increases.

Monocytes – rather large cells, in a blood smear their size reaches 15-20 microns. They contain large kernels of lobed, bean-shaped and other shapes. The cytoplasm is basophilic. Despite the fact that these cells belong to agranulocytes, small azurophilic granules, which are lysosomes, can be found in their cytoplasm in small quantities. In functional terms, these are typical macrophages, which in the peripheral bloodstream are located on the way from the red bone marrow to the tissues, where they perform specific functions. protective functions.

Percentage various types leukocytes in the peripheral bloodstream (leukocyte formula) in different types animals varies (Table 2):

Table 2. Leukocyte formula (in%)

Note : B – Basophil granulocyte; E – Eosinophilic granulocyte ; YU – Young neutrophil granulocyte; P – Band neutrophilic granulocyte;WITH – Segmented neutrophilic granulocyte.

As is clear from the table, in some animal species lymphocytes are predominant among leukocytes, while in others granular leukocytes are predominant.

Thus, a number of cells circulate in the peripheral blood, which have specific functions aimed at ensuring the body’s protection from foreign factors (antigens). These include various populations of lymphocytes, descendants of monocytes - macrophages and granular leukocytes.

Blood plates. Blood plates. In mammals, these are fragments of the cytoplasm of megakaryocytes. In birds, these are nucleated cells - platelets. Dimensions blood platelets vary within 2-4 microns. They consist of a peripheral zone - the hyalomere and a central zone - the granulomere. The hyalomere in young blood platelets is stained basophilic, and in old platelets - oxyphilic. The hyalomere contains actin, which is involved in the retraction (decrease in volume) of blood platelets.

The surface of the plasmalemma of blood platelets contains a glycolyx, the glycoproteins of which represent receptors involved in the adhesion and aggregation of blood platelets (platelet aggregation - their gluing).

According to the degree of maturity, there are 5 types of blood platelets: young, mature, old, degenerative and giant forms of irritation.

Function of blood platelets: They contain approximately 12 blood clotting factors. They take part in the coagulation of fibrinogen: fibrin → prothrombin → thrombin.

Blood plasma contains von Willebrand coagulation factor (vWF), for which there is a special receptor P Ib in the plasma membrane of the blood plates. Another receptor P IIb – IIIa binds fibrinogen, as a result of which blood platelets aggregate.

In addition, the tubular system of the cytoplasm of blood plates synthesizes cycloxygenases and prostaglandins. It is also a reservoir for Ca ions.

Platelets of birds and reptiles perform similar functions.

Ministry of Agriculture

Russian Federation

Department of Personnel Policy and Education

Don State Agrarian University

Veterinary and sanitary

blood examination

Guidelines for independent work

for students of specialty 310800 – Veterinary

and 271000 – technology of meat and meat products

p. Persianovsky 2004

UDC 619:614.31:637.66

Compiled by: prof. I. G. Seregin, prof. A.A. Kunakov – Moscow State University of Applied Biotechnology,

prof. N.F. Firsov, associate professor Soloviev – Don State Agrarian University,

Ph.D. vet. Sciences S.N. Lysenko Head of the Veterinary Department of the Administration of the Rostov Region.

Veterinary and sanitary examination of blood. Guidelines to independent work. - village Persianovsky, Don State Agrarian University, 2003 – p.

The guidelines reflect modern data on the production and processing of animal blood, drawing attention to the composition of blood, its physical and chemical properties, basic technological processes, as well as production and veterinary control during blood processing. In addition, materials on the use of blood for food, medical and technical purposes are presented.

A separate chapter contains data on veterinary and sanitary measures in the blood processing workshop, basic requirements for raw materials and finished products.

Tables – 3

Bibliography – 9 titles

Reviewers:

The guidelines were reviewed and approved by the methodological commission of the Faculty of Veterinary Medicine (protocol No. dated November 28, 2003)

Introduction

One of the sources of raw materials for obtaining food products is the blood of slaughtered animals, obtained during their processing at meat processing plants. It is distinguished by its high protein content, the nutritional value of which is similar to meat. Blood proteins help increase the moisture-binding capacity of minced meat and improve the quality of the products. The high content of protein, mineral salts, carbohydrates and vitamins suggests the widespread use of blood in the meat processing and confectionery industries. The blood of slaughtered animals is used in the production of sausages, semi-finished meat products, in baking and confectionery production, in the production of mayonnaise and other food products.

Blood as a raw material is important for the production of medicinal drugs, the range of which is quite diverse. Thus, black food albumin obtained by drying blood is used to produce hematogen and hemostimulin, which are used as hematopoietic stimulants. Blood is used to obtain hydrolysates, fibrin films, peptone, normal native serum and other drugs.

To increase the productivity of livestock and poultry, feed additives that contain blood are essential. The use of blood meal as a component in the diet of farm animals allows us to intensify the process of their growth and development and influence the reproduction of livestock.

A new direction in the use of blood is its use in the production of whole milk substitutes for young farm animals. As a result, conditions are created to reduce the consumption of milk protein for feed purposes and enrich it with amino acids and iron necessary for animals, which are contained in significant quantities in the blood.

Blood plays a significant role as a raw material for the production of certain types of technical products.

Blood is a good breeding ground for microorganisms. Therefore, when processing and storing blood, it is necessary to observe a set of veterinary and sanitary measures to ensure the sterility of raw materials and obtain products that are safe for the consumer.

When processing blood, the veterinary service, within its competence, must control the conditions of maintenance of workshops and equipment, the main technological parameters and the good quality of blood products in veterinary and sanitary terms.

Veterinary specialists need to know the properties and composition of blood, the procedure for collecting it for food, feed and technical purposes. The materials presented in the guidelines will help more effectively control the processes of blood collection and processing.

1. Composition and properties of blood

Blood is a viscous, opaque liquid bright red in the arteries and dark red with a purple tint in the veins. It has a slightly salty taste and a slightly alkaline reaction. Blood is the internal medium of the body, which provides cells with the necessary substances obtained from the external environment and carries waste products to the excretory organs.

Blood performs the protective functions of the body, participating in protection against pathogens of many infectious diseases and toxins.

It is a type of connective tissue and consists of cells and intercellular substance. The intercellular substance - the liquid part of the blood - is plasma. Plasma contains formed elements: red blood cells, leukocytes and platelets. Blood content and components varies from animal to animal.

Blood as one of critical systems the body plays a big role in its life. Thanks to a widely developed network blood capillaries it comes into contact with the cells of all tissues and organs, thus providing them with the possibility of nutrition and respiration. Being in close contact with tissues, blood has all the reactive properties of tissues, but its sensitivity to pathological irritations is higher and finer, and its reactivity is more expressive and more prominent. Therefore, any kind of impact on the tissues of the body is reflected in the composition and properties of the blood.
In many cases, changes in blood composition are a secondary factor caused by disruption of the physiological activity of various systems and organs. If changes in the blood affect the condition of organs and tissues, then changes in the functioning of these organs lead to changes in peripheral blood, its morphological and other properties. In case of dysfunction of organs and tissues, development pathological processes Both the biochemical and morphological composition of the blood changes. Recovery normalizes the blood picture. As a result, a blood test has great diagnostic value. Hematological studies predict the appearance of the first, vaguely expressed clinical symptoms of the disease, signal the danger of relapse, and provide control over therapy and the course of the pathological process.
In medicine, the hemoanalysis method is used for a wide variety of diseases; in some cases, the results of blood tests form the basis of diagnosis and prognosis. In veterinary practice, hematological studies have not yet been obtained wide application. Morphological analysis of blood and hematopoietic organs is of decisive differential diagnostic importance for diseases of the blood system (hemoblastosis, anemia) in animals and birds, and is used for blood parasitic diseases. At the same time, blood tests for many infectious, invasive and non-contagious diseases, in surgery and obstetrics, can provide valuable information regarding the etiology, pathogenesis, diagnosis, prognosis and medical intervention, in determining the immune reactivity of animals. Blood tests are no less important in zootechnical practice when objectively assessing the interior qualities of an animal, studying the genetics of domestic animals, constitution and class, milk and wool productivity.
Main functions of blood:
- respiratory - delivery to the periphery of the tissues and cells of the body of oxygen from the lungs, necessary for the implementation of oxidative processes;
- nutritional - transport of nutrients (glucose, amino acids, fats, vitamins, salts, and water) from the intestines, used by the body for assimilation processes and various functions;
- excretory - removal carbon dioxide and others final products metabolism (slags-urea, ammonia, keratinin, etc.) through excretory systems (lungs, intestines, liver, kidneys, skin);
- participation in neurohumoral regulation body functions (overload of mediators, hormones, metabolites, etc.);
- participation in the physical and chemical regulation of the body (temperature, osmotic pressure, acid-base balance, chemical composition colloid osmotic pressure);
- protective cellular (phagocytosis) and humoral (production of antibodies).
Unlike other organs, peripheral blood is not united into a single organ. However, it is an integral system with a strictly defined morphological structure and constant, diverse functions, subject to precise regulation and coordination. As a mobile internal environment of the body, blood consists of a liquid part - plasma (55-60% of the total blood mass) and formed elements (40-45%) - red blood cells (erythrocytes), white blood cells (leukocytes); blood platelets (platelets). The red color of blood and the lack of transparency depend on the huge number of red blood cells it contains. Leukocytes are colorless, which is why they are called “white blood cells.”
Cellular elements are fairly evenly distributed in the blood plasma, but their total number and percentage between them in different species of animals, in various organs of the same animal are not the same. Cellular elements are formed in hematopoietic organs(bone marrow, spleen, lymph nodes, as well as thymus, tonsils and lymphatic formations V gastrointestinal tract), where they are produced, so their number in the latter is much greater than in the circulating blood. The quantitative composition of blood cellular elements is determined not only by replenishment from the hematopoietic organs, but also by the rate of their destruction. Under physiological conditions, the processes of hematopoiesis and blood destruction are in strict coordination, regulated by humoral, hormonal and nervous pathways, ensuring constancy cellular composition blood. Based on this, the concept of “blood system” was introduced, including peripheral blood, hematopoietic and hematopoietic organs, as well as the neurohumoral apparatus for their regulation.
The most important function in the animal’s body is performed by the formed elements of blood, the main part of which are red blood cells. The total surface of all red blood cells is much larger than the surface of the human body. Thanks to this, red blood cells capture and transport a sufficient amount of oxygen, ensuring the full functioning of all organs and tissues. This blood function is performed by the respiratory pigment hemoglobin, found in red blood cells, a complex protein substance containing iron. In addition to transporting oxygen from the lungs to the tissues of the body and carbon dioxide from the tissues to the lungs, red blood cells also take part in the transport of amino acids and the adsorption of toxins and viruses. The presence of oxygen in red blood cells gives arterial blood brighter red color, and carbon dioxide content colors venous blood in cherry red color. If water is added to whole blood, hemolysis occurs - hemoglobin goes into solution and the blood becomes transparent.
The function of leukocytes is phagocytosis of bacteria and foreign bodies, i.e. the role of defenders of the body. Leukocytes include nucleic acids, proteins, carbohydrates, lipids, various enzymes necessary for normal life body. Each type of leukocyte has its own morphologically defined characteristics associated with specific functions. Leukocytes contain various types granules (basophilic, eosinophilic, neutrophilic and azurophilic), performing a variety of functions.
Basophils contain heparin, which prevents blood clotting. With increasing blood clotting, which can lead to blockage of blood vessels, the amount of heparin, which neutralizes the danger, increases.
Eosinophils play vital role at allergic conditions, i.e. when hypersensitivity to some substance.
Neutrophils (microphages) are the first to perform a protective function during inflammatory processes. They have the ability to phagocytose (devour) staphylococci, streptococci, destroy red blood cells, detritus and digest them within themselves. Monocytes (macrophages) devour the remains of dead cells.
Lymphocytes have a poor granularity; they participate in protective processes and metabolism. Lymphocytes located in the lymph nodes begin to fight when microbes try to penetrate deep into the body.
Platelets take an active part in blood clotting. When bleeding from a vessel, the liquid fibrinogen protein dissolved in the blood plasma passes into an insoluble state - fibrin, which falls out in the form of threads and, forming clots (thrombi), clogs the hole in the damaged vessel, and the bleeding stops.
Blood plasma has bactericidal and antitoxic properties. It contains all known chemical elements, various nutrients, salts, alkalis, acids, gases, vitamins, enzymes, hormones and trace elements, many of which (iron, copper, nickel, cobalt) take part in hematopoiesis.
Blood serum is the liquid part of blood without formed elements and fibrinogen, which, when coagulated, turns into a clot. It contains water, proteins, carbohydrates, fats and mineral compounds, as well as enzymes, hormones, immune bodies, etc. Serum is the carrier of innate and acquired immunity against certain diseases, and it also indicates that a given object has suffered certain diseases . Serum perceives substances internal secretion and metabolic products. The features inherent in blood serum as a carrier of individual properties depend on the nature of the protein bodies it contains (agglutinins, antitoxins, bacteriolysins, precipitins and other substances).
Most of the inorganic compounds and gases are in a dissolved state in the liquid part of the blood, but some of them, oxygen and most enzymes are found in cellular elements, i.e. in erythrocytes (for example, catalase, etc.), leukocytes (oxidase, lipase and etc.) and in platelets (thrombokinase). Oxygen is in bound state with hemoglobin of erythrocytes in the form of oxyhemoglobin (HbO2).
Salts are contained in plasma in the form of anions and cations and take an active part in maintaining osmotic pressure, which in humans is 6.8-7.3 atm. at 37 °C. The blood reaction is slightly alkaline, close to neutral (pH 7.4).
The total blood volume in a horse is 9.8% of body weight, in a cow 8.1%, in a pig - 4.6%. Water in the blood is 79%, and solid substances are 21%, of which inorganic compounds account for 1.0%, and organic substances - 20, including proteins - 19%. From blood protein compounds highest value has hemoglobin contained in red blood cells. Proteins also include plastic substances of cellular elements, albumins and globulins dispersed in plasma. Blood proteins ensure the maintenance of oncotic pressure levels. Blood viscosity depends on the presence of formed elements, their quantity and volume, as well as colloidal properties protein particles.
Plasma and serum are transparent, with a slightly yellowish or greenish tint due to dissolved lute pigments and bilirubin. The density of blood in different animals ranges on average from 1.040 to 1.060, and of serum from 1.020 to 1.030. Freshly received blood quickly clots, releasing 0.3-0.5% fibrin, drops out of the plasma, and as a result, serum is obtained, consisting of 90% water and 10% solid substances (albumin and globulin - 7-8%, sodium chloride - 0 .6, glucose - 0.1, fat - 0.5 and urea - 0.03%).

Blood is a viscous, opaque liquid that is bright red in the arteries and dark red with a purple tint in the veins. It has a slightly salty taste and a slightly alkaline reaction. Blood is the internal medium of the body, which provides cells necessary substances, obtained from the external environment, and removes waste products to the excretory organs.

Blood performs the protective functions of the body, participating in protection against pathogens of many infectious diseases and toxins.

It is a type of connective tissue and consists of cells and intercellular substance. Intercellular substance-- the liquid part of blood -- is plasma. Plasma contains formed elements: red blood cells, leukocytes and platelets. The content of blood and its components varies from animal to animal.

In almost all animals, 50% of the blood circulates in circulatory system, 16% is in the spleen, 20% in the liver parenchyma and 14% in the skin. blood veterinary sanitary fur

The particle size of blood cells depends on the type of animal. The separation of blood into serum and a clot with formed elements is possible only outside the body. The mass of red blood cells and their ability to stick together affect their sedimentation rate and the separation of plasma and formed elements. Plasma without fibrinogen is blood serum.

Complete separation of horse blood fractions occurs after 45 minutes, followed by pig blood in time. The blood of large and small ruminants is most difficult to separate.

The chemical composition of the blood circulating in the body of an animal is constant. Blood contains proteins, fats, carbohydrates, minerals, enzymes, vitamins and hormones. In animals of different species, the content of these components is not the same.

The amount of water in the blood of cattle decreases with age. On the contrary, the content of total nitrogen and dry residue is generally higher in adult cattle than in calves. An increase in the content of total nitrogen is also observed with an increase in fatness. The highest amount of protein in the blood of cattle is established at the age of 3 years, then it decreases and reaches a minimum by 12 years.

The mineral composition of blood is quite diverse. Wherein greatest number inorganic substances contained in shaped elements. So, general content minerals in the blood is 0.85--0.9% (in formed elements 1.2%), water 79.0--81.2%, dry matter 17.9--21.0% (in horses, respectively 74.9% and 25.1%), the total amount of proteins is 16.4--18.9% (in horses - 23.6%), the hemoglobin content ranges from 9.3% to 14.2% (in horses up to 16.7;%).[Veterinary and sanitary examination of blood. Guidelines for independent work. - village Persianovsky, Don State Agrarian University, 2003 - p.]

The main plasma proteins are albumin, globulins and fibrinogen.

Fibrinogen is found in plasma and absent in serum. It is involved in blood clotting, turning into fibrin.

The listed plasma proteins are complete, as they contain the entire complex essential amino acids. The most valuable of them is fibrinogen, which contains more tryptophan, lysine and methionine.

The main protein of formed elements is hemoglobin. It is a complex protein consisting of a protein part - globin and a non-protein part - heme. Hemoglobin is the main part of red blood cells and is contained in them in an amount of 30-40%. Hemoglobin carries oxygen to cells, where intense processes of biological oxidation occur. Its concentration in the blood of different animals is not the same due to differences in the number of red blood cells and their size. As a result of the oxidation of heme, its discoloration occurs, which is of great practical importance for expanding the scope of use of blood and formed elements for food purposes. [Veterinary and sanitary examination of blood. Guidelines for independent work. - village Persianovsky, Don State Agrarian University, 2003 - p.]

Along with protein substances, the composition of blood and its fractions includes non-protein nitrogenous and non-nitrogenous substances, minerals, pigments, vitamins, and lipids.

Nitrogenous non-protein substances include urea, ammonia, amino acids, creatine, creatinine, uric acid, purines and other compounds. Nitrogen-free substances include mainly glucose, fructose, glycogen, as well as lactic and pyruvic acids.

TO minerals include sodium, potassium, magnesium chlorides, sodium bicarbonate, calcium carbonate, sodium sulfate, calcium phosphate, phosphate salts of potassium, sodium, etc.

Blood pigments include hemoglobin, bilirubin, biliverdin, lipochrome, lutein, urobilin.

The blood density of various slaughter animals has similar indicators: 1040-1065 kg/m3.

Blood viscosity mainly depends on the content of formed elements and, to a lesser extent, on the concentration of protein in plasma. With increasing fatness of cattle, the viscosity of blood serum increases. Whole blood has a viscosity of 3.4-6.8 units, serum - 1.55-1.90 units. in relation to water.

The reaction of the blood environment of slaughtered animals is slightly alkaline, the pH of the blood of cattle is 7.4, small ruminant lambing is 7.5, pigs are 7.49, horses are 7.42, rabbits are 7.58.

When heated, blood proteins coagulate, as a result they lose solubility and precipitate. The temperature of protein coagulation is specific: albumin coagulates at a temperature of 67°C, fibrinogen at 56°C. Complete coagulation of blood proteins occurs at a temperature of 80°C.

Released from blood vessel The blood initially flows out quickly, but after a short period of time it loses its fluid properties and coagulates, forming a clot. Blood clotting in different animals occurs at different rates. Thus, the blood of cattle coagulates in 6.5 minutes, of small cattle - 2.6 minutes, pigs - 3.5 minutes, horses - 11.5 minutes.

Blood clotting is a complex enzymatic process consisting of a chain of interconnected reactions. IN this process 13 factors are involved. As a result of blood clotting processes, the soluble protein fibrinogen contained in plasma is converted into insoluble fibrin. If freshly released blood is stirred, the resulting fibrin strands are wound around the stirrer and the blood remains liquid. Such blood, devoid of fibrin, is called defibrinated. As the temperature drops, blood clotting slows down. Thus, the blood of different animals at a temperature of 10°C clots only after 10-20 minutes, the rate of blood clotting at a temperature of 13.7°C is 18.5 minutes, at a temperature of 39.9°C it is 2.75 minutes.

The blood clotting process can be accelerated by various factors. These include the use of vitamin K, which promotes the formation of the protein prothrombin in the liver.

The main reasons that slow down blood clotting are a lack of one or more blood clotting factors and an excess of anticoagulants. In addition, an insufficient number of platelets contributes to the slowdown of blood clotting - Werlhof's disease, hepatitis, phosphorus poisoning, etc., vitamin deficiencies and hypovitaminosis K, as well as causes that impair the synthesis of thrombin, proconvertin and fibrinogen, excessive formation of heparin, inactivation of prothrombin, thrombin , a large intake of tissue fibrinokinase into the blood.

In practice, artificial prevention of blood clotting is important. The process of preventing blood clotting by introducing certain substances into the blood is called stabilization. Blood stabilization is due to the exclusion of one of the components included in the blood coagulation system. Among the most common stabilization methods, those based on the exclusion of calcium ions from the blood coagulation system should be mentioned. Stabilizers of this type include salts of oxalic, phosphoric, hydrofluoric, citric and trihydroxyglutaric acids. For therapeutic and research purposes, blood is stabilized with sodium citrate, and for food purposes - with salts of pyrophosphoric acid.

Heparin, found in the liver, lungs and muscles, hirudin, formed in oral cavity leeches are natural blood stabilizers. Heparin delays blood clotting in blood vessels, which can occur as a result of platelet destruction and activation of thrombokinase. The activity of bovine heparin is twice that of porcine heparin, so pig blood clots faster.