Examining blood under a microscope, one can detect rather large cells with nuclei; they look transparent. These are white blood cells or leukocytes.

LEUKOCYTES (from Greek leukos - white and from Greek kytos - receptacle, here - cell), colorless. human and animal blood cells. All types of L. (lymphocytes, monocytes, basophils, eosinophils, and neutrophils) have a nucleus and are capable of active amoeboid movement. In the body, they absorb bacteria and dead cells, and produce antibodies. 1 mm3 of the blood of a healthy person contains 4-9 thousand liters.

Their amount varies depending on the food intake and physical activity. Leukocytes are divided into granulocytes (containing granules, granules) and agranulocytes (non-granular leukocytes).

Leukocytosis (leukocytosis, leukos - white, cytos - cell) - pathological reaction organism, manifested by an increase in the content of leukocytes in the blood over 9x109/l.


1. Leukopenia (leukopenia, leukos - white, penia - poverty) is a pathological reaction of the body, manifested by a decrease in the content of leukocytes in the blood below 4´ 109 / l.
   

   GRANULOCITES, leukocytes of vertebrates and humans, containing grains (granules) in the cytoplasm. Formed in the bone marrow. According to the ability of the grains to be painted special. paints are divided into basophils, neutrophils, eosinophils. Protect the body from bacteria and toxins.
   

   AGRANULOCYTES (non-granular leukocytes), leukocytes of women and humans, not containing grains (granules) in the cytoplasm. A. - immunological cells. and phagocytic system; divided into lymphocytes and monocytes.
   

   Granular leukocytes are divided into eosinophils (the grains of which are stained with acidic dyes), basophils (the grains of which are stained with basic dyes), and neutrophils (the grains of which are stained with both dyes).
   

   EOSINOPHILE, one of the types of white blood cells. They are stained with acid dyes, including eosin, in red. Participate in allergic body reactions.
   

   BASOPHILES, cells containing structures in the cytoplasm stained with basic (alkaline) dyes, the type of granular blood leukocytes, and also determined. anterior pituitary cells.
   

   NEUTROPHILS, (from Latin neuter - neither one nor the other and ... phil) (microphages), one of the types of leukocytes. N. are capable of phagocytosis of small foreign particles, including bacteria, and can dissolve (lyse) dead tissue.
   

   Agranulocytes are divided into lymphocytes (cells with a round dark nucleus) and monocytes (with an irregularly shaped nucleus).
   

   LYMPHOCYTES (from lymph and ... cyto), one of the forms of non-granular leukocytes. Allocate 2 main. class L. V-L. originate from the bursa of Fabricius (in birds) or bone marrow; they form plasma. cells that produce antibodies. T-L. originate from the thymus. L. are involved in the development and maintenance of immunity, and also, probably, supply nourishment. in-va other cells.
   

   MONOCYTES (from mono ... and ... cyto), one of the types of leukocytes. Capable of phagocytosis; released from the blood into the tissues when inflamed. reactions, function as macrophages.
   

   THYMUS GLAND (thymus gland, thymus), center. organ of the vertebrate immune system. In most mammals, it is located in the area anterior mediastinum. well developed in young age. Participates in the formation of immunity (produces T-lymphocytes), in the regulation of growth and overall development of the body.
   

   Leukocytes are complex in structure. The cytoplasm of leukocytes in healthy people is usually pink, the granularity in some cells is red, in others it is purple, in others it is dark blue, and in some there is no color at all. The German scientist Paul Erlig processed blood smears with a special dye and separated white blood cells into granular and non-granular. His research was deepened and developed by D.L. Romanovsky. He found out which paths blood cells take in their development. The blood-staining solution he compiled helped reveal many of its secrets. This discovery entered science as the famous principle of "Romanovsky coloring". The German scientist Arthur Pappengein and the Russian scientist A.N. Kryukov created a coherent theory of hematopoiesis.
   

   By the number of leukocytes in the blood, a person's disease is judged. Leukocytes can move independently, pass through tissue gaps and intercellular spaces. The most important function of leukocytes is protective. They fight microbes, absorb them and digest them (phagocytosis); discovered by I.I. Mechnikov in 1883. Through persistent long-term studies, he proved the existence of phagocytosis.
   

   MACROPHAGES (from macro ... and ... phages) (polyblasts), cells of mesenchymal origin in women and humans, capable of actively capturing and digesting bacteria, cell debris, and other foreign or toxic particles for the body (see Phagocytosis). M. include monocytes, histiocytes, etc.
   

   MICROPHAGES, same as neutrophils,
   

   Leukocyte formula the percentage of different forms of leukocytes in the blood (in a stained smear). Changes in the leukocyte formula may be typical for a particular disease.
   

   2. Blood plasma, the concept of serum. Plasma proteins
   

   Blood plasma is the liquid part of the blood. Blood plasma contains the formed elements of blood (erythrocytes, leukocytes, platelets). Changes in the composition of blood plasma are of diagnostic value in various diseases(rheumatism, diabetes and etc.). Medicinal preparations (albumin, fibrinogen, gamma globulin, etc.) are prepared from blood plasma. There are about 100 different proteins in human blood plasma. According to their mobility during electrophoresis (see below), they can be roughly divided into five factions:albumin, α 1 -, α 2 -, β- And γ-globulins. The division into albumin and globulin was originally based on a difference in solubility: albumins are soluble in clean water, and globulins - only in the presence of salts.
   

   In quantitative terms, among plasma proteins, the most represented albumen(about 45 g/l), which plays an essential role in maintaining the colloid osmotic pressure in the blood and serves as an important reserve of amino acids for the body. Albumin has the ability to bind lipophilic substances, as a result of which it can function as a carrier protein for long-chain fatty acids, bilirubin, medicinal substances, some steroid hormones and vitamins. In addition, albumin binds Ca 2+ and Mg 2+ ions.
   

   The albumin fraction also includes transthyretin (prealbumin), which, together with thyroxin-binding globulin [TSGl (TBG)] and albumin, transports the hormone thyroxine and its metabolite iodothyronine.
   

   The table shows other important properties globulins blood plasma. These proteins are involved in the transport of lipids, hormones, vitamins and metal ions, they form important components of the blood coagulation system; the fraction of γ-globulins contains antibodies of the immune system.
   

   3. Hematopoiesis. Factors of erythropoiesis, leukopoiesis and thrombopoiesis. The concept of the blood system (G.F. Lang)
   

   Hematopoiesis is the process of generating mature blood cells, which the human body produces no less than 400 billion per day. Hematopoietic cells are derived from a very small number of totipotent stem cells that differentiate to give rise to all blood cell lines. Totipotent stem cells are the least specialized. Pluripotent stem cells are more specialized. They are able to differentiate, producing only certain cell lines. There are two populations of pluripotent cells - lymphoid and myeloid.
   

   
   

   RBCs are derived from a pluripotent bone marrow stem cell that can differentiate into erythropoiesis progenitor cells. These cells are morphologically indistinguishable. Next, the differentiation of precursor cells into erythroblasts and normoblasts occurs, the latter lose their nucleus in the process of division, all in more accumulating hemoglobin, reticulocytes and mature erythrocytes are formed, which come from the bone marrow into the peripheral blood. Iron binds to the circulating transport protein transferrin, which binds to specific receptors on the surface of erythropoiesis progenitor cells. The main part of iron is included in the composition of hemoglobin, the rest is reserved in the form of ferritin. Upon completion of maturation, the erythrocyte enters the general circulation, its lifespan is approximately 120 days, then it is captured by macrophages and destroyed, mainly in the spleen. Heme iron is included in the composition of ferritin, and can also re-bind with transferrin and be delivered to bone marrow cells.
   

   The most important factor in the regulation of erythropoiesis is erythropoietin, a glycoprotein with a molecular weight of 36,000. It is produced mainly in the kidneys under the influence of hypoxia. Erythropoietin controls the differentiation of progenitor cells into erythroblasts and stimulates hemoglobin synthesis. Erythropoiesis is also affected by other factors - catecholamines, steroid hormones, growth hormone, cyclic nucleotides. Essential factors for normal erythropoiesis are vitamin B12 and folic acid and enough iron.
   

   Leukopoiesis(leucopoiesis, leucopoiesis: leuco-+ Greek poiesis production, education; synonym: leukogenesis, leukocytopoiesis) - the process of formation of leukocytes
   

   Thrombocytopoiesis(thrombocytopoesis; platelet + Greek poiēsis production, formation) - the process of formation of platelets.
   

   The blood system the concept was introduced by the Russian therapist Georgy Fedorovich Lang (1875-1948).
   

   Denotes a system that includes peripheral blood, organs of hematopoiesis and blood destruction, as well as the neurohumoral apparatus of their regulation.
   

   4. Serrated and smooth tetanus. The concept of muscle tone. The concept of optimum and pessimum
   

   IN vivo the skeletal muscle from the central nervous system receives not single impulses, but a series of impulses following one after another at certain intervals, to which the muscle responds with a prolonged contraction. Such a prolonged muscle contraction that occurs in response to rhythmic stimulation is called tetanic contraction or tetanus. There are two types of tetanus: serrated and smooth.
   

   If each subsequent excitation impulse enters the muscle during the period when it is in the shortening phase, then a smooth tetanus occurs, and if in the relaxation phase, a dentate tetanus occurs.
   

   The amplitude of tetanic contraction exceeds the amplitude of a single muscle contraction. Proceeding from this, Helmholtz explained the process of tetanic contraction by a simple superposition, i.e., a simple summation of the amplitude of one muscle contraction with the amplitude of another. However, later it was shown that in tetanus there is not a simple addition of two mechanical effects, since this sum can be either larger or smaller. N. E. Vvedensky explained this phenomenon from the point of view of the state of excitability of the muscle, introducing the concept of the optimum and pessimum of the frequency of stimulation.
   

   Optimal is the frequency of irritation at which each subsequent irritation is carried out in a phase of increased excitability. In this case, the tetanus will be maximum in amplitude - optimal.
   

   Pessimal is such a frequency of irritation at which each subsequent irritation is carried out in a phase of reduced excitability. In this case, the tetanus will be minimal in amplitude - pessimal.
   

   Tone
   muscles - basic level
   muscle activity provided by its tonic contraction.
   

   In normal
   able
   rest, all motor units of various muscles are in a well-organized complex background stochastic activity. Within one muscle in a given random
   moment
   time, some motor units are excited, others are at rest. At the next random moment in time, other motor units are activated. Thus, the activation of motor units is a stochastic function of two random variables - space and time. Such activity of motor units provides tonic contraction of the muscle, the tone of this muscle and the tone of all muscles of the motor system. A certain mutual relation of the tone of various muscle groups provides the posture of the body.
   

   In the basis of the control of muscle tone and body posture at rest or during movement, the general strategy of control in living
   systems - forecasting
   

   5. Modern biophysical and physiological conception of the mechanism of the occurrence of membrane potential and excitation
   

   Each cell at rest is characterized by the presence of a transmembrane potential difference (resting potential). Typically, the charge difference between the inner and outer surfaces of the membranes is -30 to -100 mV and can be measured using an intracellular microelectrode.
   

   The creation of the resting potential is provided by two main processes - the uneven distribution of inorganic ions between the intra- and extracellular space and the unequal permeability of the cell membrane for them. Analysis chemical composition extra- and intracellular fluid indicates an extremely uneven distribution of ions
   

   Studies using microelectrodes have shown that the resting potential of a frog skeletal muscle cell ranges from -90 to -100 mV. Such a good agreement between the experimental and theoretical data confirms that the resting potential is largely determined by the simple diffusion potentials of inorganic ions.
   

   Important for the emergence and maintenance of membrane potential is the active transport of sodium and potassium ions through cell membrane. In this case, the transfer of ions occurs against the electrochemical gradient and is carried out with the expenditure of energy. Active transport of sodium and potassium ions is carried out by Na + /K + - ATPase pump.
   

   In some cells, active transport is directly involved in the formation of the resting potential. This is due to the fact that the potassium-sodium pump removes more sodium ions from the cell at the same time than it brings potassium into the cell. This ratio is 3/2. Therefore, the potassium-sodium pump is called electrogenic, since it itself creates a small, but D.C. positive charges from the cell, and therefore makes a direct contribution to the formation of a negative potential inside it.
   

   The membrane potential is not a stable value, since there are many factors that affect the value of the resting potential of the cell: exposure to an irritant, changes in the ionic composition of the environment, exposure to certain toxins, disruption of oxygen supply to the tissue, etc. In all cases when membrane potential decreases, they speak of membrane depolarization, the opposite shift of the resting potential is called hyperpolarization.
   

   The membrane theory of excitation is a theory that explains the emergence and spread of excitation in the central nervous system by the phenomenon of semipermeability of neuronal membranes, which restrict the movement of ions of one type and pass ions of another type through ion channels.
   

   6. Skeletal muscles as an example of pastcellular structures - symplast
   

   Skeletal muscles are part of the structure of the musculoskeletal system, are attached to the bones of the skeleton and, when contracted, set in motion individual parts of the skeleton.
   

   They are involved in maintaining the position of the body and its parts in space, provide movement when walking, running, chewing, swallowing, breathing, etc., while generating heat. Skeletal muscles have the ability to be excited under the influence of nerve impulses. Excitation is carried out to contractile structures (myofibrils), which, while contracting, perform a motor act - movement or tension.
   

   A person has about 600 muscles and most of them are paired. In each muscle, an active part (muscle body) and a passive part (tendon) are distinguished.
   

   Muscles, the action of which is opposite, are called antagonists, unidirectional - synergists. The same muscles in different situations can act in both capacities.
   

   According to the functional purpose and direction of movements in the joints, the muscles are flexors and extensors, adductors and abductors, sphincters (compressive) and dilators.
   

   Symplast - (from the Greek syn - together and plastos - fashioned), a type of tissue in animals and plants, characterized by the absence of boundaries between cells and the location of nuclei in a continuous mass of cytoplasm. For example, striated muscles in animals, multinuclear protoplasts of some unicellular algae.
   

   7. Regulation of the work of the heart (intracellular, heterometric and homeometric). Starling's Law. Influence of the sympathetic and parasympathetic nervous system on the activity of the heart
   

   Although the heart itself generates impulses that cause it to contract, the activity of the heart is controlled by a number of regulatory mechanisms that can be divided into two groups - extracardiac mechanisms (extracardiac), which include nervous and humoral regulation, and intracardiac mechanisms (intracardiac).
   

   The first level of regulation is extracardiac (nervous and humoral). It includes the regulation of the main factors that determine the magnitude of minute volume, frequency and strength of heart contractions with the help of the nervous system and humoral influences. Nervous and humoral regulation are closely related and form a single neuro-humoral mechanism for regulating the work of the heart.
   

   The second level is represented by intracardiac mechanisms, which, in turn, can be divided into mechanisms that regulate the work of the heart at the organ level, and intracellular mechanisms that regulate mainly the strength of heart contractions, as well as the rate and degree of myocardial relaxation.
   

   The central nervous system constantly controls the work of the heart
   through nerve impulses. Inside the cavities of the heart itself and in the walls of large vessels are located nerve endings- receptors that perceive pressure fluctuations in the heart and blood vessels. Impulses from the receptors cause reflexes that affect the work of the heart. There are two types of nervous influences on the heart: one is inhibitory,
   i.e., reducing the frequency of contractions of the heart, others - accelerating.
   

   Impulses are transmitted to the heart through nerve fibers from nerve centers located in oblong and spinal cord. Influences that weaken the work of the heart are transmitted through the parasympathetic nerves, and those that enhance its work are transmitted through the sympathetic.
   

   For example, a person's heart beats faster when he quickly gets up from a prone position. The fact is that the transition to a vertical position leads to the accumulation of blood in the lower part of the body and reduces the blood supply to the upper part, especially the brain. To restore blood flow in the upper body, impulses are sent from the vascular receptors to the central nervous system.
   

   From there, impulses are transmitted to the heart along the nerve fibers, accelerating the contraction of the heart. These facts are a clear example of self-regulation of the activity of the heart.
   

   Painful stimuli also change the rhythm of the heart. Painful impulses enter the central nervous system and cause a slowdown or acceleration of the heartbeat. Muscular work always affects the activity of the heart. Putting into work large group muscles, according to the laws of the reflex, excites the center, accelerating the activity of the heart. Big influence emotions are brought to the heart. Under the influence of positive
   emotions, people can do colossal work, lift weights, run long distances. Negative emotions, on the contrary, reduce the efficiency of the heart and can lead to disturbances in its activity.
   

   Along with nervous control, the activity of the heart is regulated
   chemicals that constantly enter the blood. This method of regulation through liquid media is called humoral regulation.
   The substance that inhibits the work of the heart is acetylcholine.
   

   The sensitivity of the heart to this substance is so great that at a dose of 0.0000001 mg, acetylcholine clearly slows down its rhythm. Another chemical substance, adrenaline, has the opposite effect. Adrenaline, even in very small doses, enhances the work of the heart.
   

   For example, pain causes the release of several micrograms of adrenaline into the blood, which noticeably changes the activity of the heart. In medical practice, adrenaline is sometimes injected directly into a stopped heart to force it to contract again. The normal functioning of the heart depends on the amount of potassium and calcium salts in the blood. An increase in the content of potassium salts in the blood depresses, and calcium increases
   the work of the heart. Thus, the work of the heart changes with changes in environmental conditions and the state of the organism itself.
   

   Starling's law of the heart, which shows the dependence of the strength of heart contractions on the degree of myocardial stretching. This law applies not only to the heart muscle as a whole, but also to an individual muscle fiber. An increase in the force of contraction during cardiomyocyte stretching is due to a better interaction between the contractile proteins actin and myosin, and under these conditions, the concentration of free intracellular calcium (the main regulator of the strength of heart contractions at the cellular level) remains unchanged. In accordance with Starling's law, the force of myocardial contraction is greater, the more the heart muscle is stretched during diastole under the influence of the inflowing blood. This is one of the mechanisms that ensure an increase in the strength of heart contractions adequate to the need to pump into the arterial system exactly the amount of blood that flows to it from the veins.
   

   8. Blood pressure in different parts of the vascular bed, the method of registration and determination
   

   Blood pressure is the hydrodynamic pressure of blood in the vessels, due to the work of the heart and the resistance of the walls of the vessels. Decreases with distance from the heart (greatest in the aorta, much lower in the capillaries, least in the veins). Normal for an adult is conditionally considered arterial pressure 100-140 mmHg (systolic) and 70-80 mmHg (diastolic); venous - 60-100 mm of water column. High blood pressure (hypertension) is a sign hypertension, low (hypotension) accompanies a number of diseases, but it is also possible in healthy people.
   

   9. Types of cardiomyocytes. Morphological differences between contractile and conductive cells
   

   	Thin and long	Elliptical	Thick and long
   Length, µm	~ 60 ё140	~ 20	~ 150 ё200
   Diameter, µm	~ 20	~ 5 e6	~ 35 e40
   Volume, µm 3	~ 15 ё45000	~ 500	135000 ё250000
   The presence of transverse tubes	A lot of	Rare or absent	Missing
   Availability of insert discs	Numerous gap junctions of cells from end to end, providing a high rate of interaction.	Lateral cell connections or end-to-end connections.	Numerous gap junctions of cells from end to end, providing a high speed of interaction.
   General view of the muscle	A large number of mitochondria and sarcomeres.	The atrial muscle bundles are separated by extensive areas of collagen.	Fewer sarcomeres, less striation

   10. Transfer of gases by blood. Oxyhemoglobin dissociation curve. Features of carbon dioxide transport
   

   The transfer (transport) of respiratory gases, oxygen, O2 and carbon dioxide, CO2 with blood is the second of the three stages of respiration: 1. external respiration, 2. transport of gases by blood, 3. cellular respiration.
   

   End stages of respiration, tissue
   respiration, biochemical oxidation are part of the metabolism. In the process of metabolism, end products are formed, the main of which is carbon dioxide. Condition
   normal life is the timely removal of carbon dioxide from the body.
   

   Mechanisms
   control of carbon dioxide transport interact with regulatory mechanisms
   acid-base balance of blood, regulation of the internal environment of the body as a whole.
   

   11. Breathing in conditions of high and low atmospheric pressure. Caisson disease. mountain sickness
   

   caisson disease - a decompression illness that occurs mostly after caisson and diving operations in violation of the rules of decompression (gradual transition from high to normal atmospheric pressure). Signs: itching, pain in the joints and muscles, dizziness, speech disorders, confusion, paralysis. Apply the sluice medical.
   

   mountain sickness - develops in high mountains due to a decrease in the partial pressure of atmospheric gases, mainly oxygen. It can be acute (a type of altitude sickness) or chronic, manifesting as cardiac and lung failure and other symptoms.
   

   12. a brief description of airway walls. Types of bronchi, morphofunctional characteristics of small bronchi
   

   Bronchi (from Greek brónchos - windpipe, trachea), branches windpipe in higher vertebrates (amniotes) and humans. In most animals, the windpipe, or trachea, is divided into two main bronchi. Only in the tuatara, a longitudinal furrow in the posterior part of the windpipe outlines paired B., which do not have separate cavities. In other reptiles, as well as in birds and mammals, B. are well developed and continue inside the lungs. In reptiles, B. of the second order depart from the main B., which can be divided into B. of the third, fourth order, etc.; B.'s division is especially difficult in turtles and crocodiles. In birds, B. of the second order are interconnected by parabronchi - channels, from which the so-called bronchioles branch off along the radii, branching and passing into a network of air capillaries. The bronchioles and air capillaries of each parabronchi merge with the corresponding formations of other parabronchi, thus forming a system of through airways. Both the main B. and some lateral B. at the ends expand into the so-called air sacs. In mammals, secondary bronchi branch off from each main bronchi and divide into ever smaller branches, forming the so-called bronchial tree. The smallest branches pass into alveolar passages, ending in alveoli. In addition to the usual secondary B., in mammals, pre-arterial secondary B. are distinguished, extending from the main B. in front of the place where they are thrown over them. pulmonary arteries. More often there is only one right pre-arterial B., which in most artiodactyls departs directly from the trachea. The fibrous walls of large B. contain cartilaginous semirings connected behind by transverse bundles of smooth muscles. B.'s mucous membrane is covered ciliated epithelium. In small B., cartilaginous semirings are replaced by individual cartilaginous grains. There are no cartilages in the bronchioles, and the annular bundles of smooth muscles lie in a continuous layer. In most birds, the first B. rings participate in the formation of the lower larynx.
   

   In humans, the division of the trachea into 2 main B. occurs at the level of the 4th-5th thoracic vertebrae. Each of the bronchi then divides into ever smaller ones, ending with microscopically small bronchioles, which pass into the alveoli of the lungs. B.'s walls are formed by the hyaline cartilaginous rings preventing B.'s falling down, and smooth muscles; from within B. are lined with a mucous membrane. Numerous lymph nodes are located along the B.'s branching, receiving lymph from lung tissues. B.'s blood supply is carried out by the bronchial arteries extending from the thoracic aorta, innervation - by the branches of the vagus, sympathetic and spinal nerves.
   

   13. Fat metabolism and its regulation
   

   Fats are an important source of energy in the body, essential component cells. Excess fats can be deposited in the body. They are deposited mainly in the subcutaneous adipose tissue, omentum, liver and other internal organs. In the gastrointestinal tract, fat breaks down into glycerol and fatty acids, which are absorbed into small intestines. Then it is again synthesized in the cells of the intestinal mucosa. The resulting fat is qualitatively different from food fat and is specific to the human body. In the body, fats can also be synthesized from proteins and carbohydrates. Fats that enter the tissues from the intestines and from fat depots are oxidized through complex transformations, thus being a source of energy. When 1 g of fat is oxidized, 9.3 kcal of energy is released. As an energy material, fat is used at rest and during long-term low-intensity physical work. At the beginning of strenuous muscle activity, carbohydrates are oxidized. But after a while, due to a decrease in glycogen stores, fats and their breakdown products begin to oxidize. The process of replacing carbohydrates with fats can be so intense that 80% of all the energy needed under these conditions is released as a result of the breakdown of fat. Fat is used as a plastic and energy material, covers various organs, protecting them from mechanical impact. Accumulation of fat in abdominal cavity provides fixation internal organs. Subcutaneous fatty tissue, being a poor conductor of heat, protects the body from excessive heat loss. Dietary fat contains some vital vitamins. The metabolism of fat and lipids in the body is complex. An important role in these processes is played by the liver, where fatty acids are synthesized from carbohydrates and proteins. Lipid metabolism is closely related to the metabolism of proteins and carbohydrates. When fasting fat reserves serve as a source of carbohydrates. Regulation fat metabolism. Lipid metabolism in the body is regulated by the central nervous system. If some nuclei of the hypothalamus are damaged, fat metabolism is disturbed and the body becomes obese or depleted.

   14. Protein metabolism. nitrogen balance. Positive and negative nitrogen balance. Regulation of protein metabolism
   

   Proteins - essential construction material cell protoplasm. They perform in the body special functions. All enzymes, many hormones, visual purple of the retina, oxygen carriers, protective substances of the blood are protein bodies. Proteins consist of protein elements - amino acids, which are formed during the digestion of animal and vegetable protein and enter the blood from the small intestine. Amino acids are divided into essential and non-essential. Indispensable are those that the body receives only with food. The nonessentials can be synthesized in the body from other amino acids. The value of food proteins is determined by the content of amino acids. That is why dietary proteins are divided into two groups: complete, containing all the essential amino acids, and inferior, which lack some of the essential amino acids. Animal proteins are the main source of complete proteins. Vegetable proteins (with rare exceptions) are incomplete. In tissues and cells, there is a continuous destruction and synthesis of protein structures. In a conditionally healthy body of an adult, the amount of decomposed protein is equal to the amount of synthesized protein. Since the balance of protein in the body is of great practical importance, many methods have been developed to study it. The regulation of protein balance is carried out by humoral and nervous pathways (through the hormones of the adrenal cortex and pituitary gland, diencephalon).

   15. Heat dissipation. Methods for transferring heat from a heat surface
   

   The ability of the human body to maintain a constant temperature is due to complex biological and physico-chemical processes of thermoregulation. Unlike cold-blooded (poikilothermic) animals, the body temperature of warm-blooded (gamoiothermic) animals is maintained at a certain level during fluctuations in the external temperature, which is most beneficial for the life of the organism. Maintaining the heat balance is carried out due to the strict proportionality in the formation of heat and in its return. The amount of heat generation depends on the intensity chemical reactions characterizing the level of metabolism. Heat transfer is regulated mainly by physical processes (heat radiation, heat conduction, evaporation).
   

   The body temperature of humans and higher animals is maintained at a relatively constant level, despite fluctuations in the temperature of the external environment. This constancy of body temperature is called isothermia. Isothermy in the process of ontogenesis develops gradually.
   

   The constancy of body temperature in a person can be maintained only if the heat generation and heat loss of the body are equal. This is achieved through physiological thermoregulation, which is usually divided into chemical and physical. The ability of a person to withstand the effects of heat and cold, while maintaining a stable body temperature, has known limits. At excessively low or very high temperature environment, protective thermoregulatory mechanisms are insufficient, and body temperature begins to drop or rise sharply. In the first case, a state of hypothermia develops, the second - hyperthermia.
   

   The formation of heat in the body occurs mainly as a result of chemical reactions of metabolism. During the oxidation of food components and other reactions of tissue metabolism, heat is generated. The amount of heat generation is closely related to the level of metabolic activity of the body. Therefore, heat production is also called chemical thermoregulation.
   

   Chemical thermoregulation has a special importance maintaining a constant body temperature in conditions of cooling When the ambient temperature decreases, there is an increase in the intensity of metabolism and, consequently, heat generation. In humans, an increase in heat generation is noted in 1 case when the ambient temperature falls below the optimum temperature or comfort zone. In ordinary light clothes, this zone is in the range of 18-20°, and for a naked person -28°C.
   

   The total heat generation in the body occurs during the chemical reactions of metabolism (oxidation, glycolysis), which constitutes the so-called primary heat and when the energy of high-energy compounds (ATP) is spent to perform the slave (secondary heat). 60-70% of energy is dissipated in the form of primary heat. The remaining 30-40% after ATP splitting provide muscle work, various processes su-secretion, etc. But even in this case, one or another part of the energy then passes into heat. Thus, secondary heat is also formed due to exothermic chemical reactions, and with a reduction muscle fibers the result of their friction. Ultimately, either all the energy, or the overwhelming part of it, passes into heat.
   

   The most intense heat generation in the muscles during their contraction. Relatively low motor activity leads to an increase in heat generation by 2 times, and hard work - by 4-5 times or more. However, under these conditions, heat loss from the body surface increases significantly.
   

   With prolonged cooling of the body, involuntary periodic contractions occur skeletal muscles. In this case, almost all the metabolic energy in the muscle is released in the form of heat. Activation of the sympathetic nervous system in cold conditions stimulates lipolysis in adipose tissue. Free fatty acids are released into the bloodstream and subsequently oxidized with the formation of a large amount of heat. Finally, the importance of heat production is associated with an increase in the functions of the adrenal glands and the thyroid gland. The hormones of these glands, increasing the metabolism, cause increased heat generation. It should also be borne in mind that all physiological mechanisms, which regulate oxidative processes, affect at the same time the level of heat generation.
   

   The release of heat by the body is carried out by radiation and evaporation.
   

   Radiation is lost approximately 50-55% went into environment by emitting radiation in the infrared part of the spectrum. The amount of heat dissipated by the body (environment with radiation) is proportional to the surface area of ​​the parts of the body that come into contact with air and the difference in the average temperatures of the skin and the environment. Radiation emission ceases if the temperature of the skin and the environment equalizes.
   

   Heat conduction can occur by conduction and evaporation. By conduction, heat is lost when parts of the human body come into direct contact with other physical media. In this case, the amount of heat lost is proportional to the difference between the average temperatures of the contacting surfaces and the time of thermal contact. Convection is a method of heat transfer of the body, carried out by transferring heat by moving air particles.
   

   Heat is dissipated by convection when a stream of air flows around the surface of the body at a lower temperature than the air temperature. The movement of air currents (wind, ventilation) increases the amount of heat given off. By conducting heat, the body loses 15-20% of heat, while convection is a more extensive heat transfer mechanism than conduction.
   

   Evaporative heat transfer is a way for the body to dissipate heat (about 30%) into the environment due to its expenditure on the evaporation of sweat or moisture from the surface of the skin and mucous membranes of the respiratory tract. At an ambient temperature of 20 ″, the evaporation of moisture in a person is 600-800 g per day. During the transition to 1 g of water, the body loses 0.58 kcal of heat. If the external temperature exceeds the average skin temperature, then the body gives off heat to the external environment by radiation and conduction, and we absorb heat from the outside. Evaporation of liquid from the surface occurs when the air humidity is less than 100%.
   Microscopic fungi as the main producers of various mycotoxins GENERAL VIEW OF THE STRUCTURE AND FUNCTIONS OF THE NERVOUS SYSTEM

   2014-11-07

Our body is an amazing thing. It is able to produce all the substances necessary for life, cope with a variety of viruses and bacteria, and finally provide us with a normal life.

Where are leukocytes formed in humans?

Human blood is made up of shaped elements and plasma. Leukocytes are one of these formed elements along with erythrocytes and platelets. They are colorless, have a nucleus and can move independently. They can be seen under a microscope only after preliminary coloring. From the organs included in where leukocytes are formed, they go into the bloodstream and body tissues. They can also freely pass from the vessels to the adjacent tissues.

Leukocytes move in the following way. Having fixed on the wall of the vessel, the leukocyte forms a pseudopodia (pseudopodia), which it pushes through this wall and clings to the tissue from the outside. Then it squeezes through the resulting gap and actively moves among other cells of the body leading a "sedentary" lifestyle. Their movement resembles the movement of an amoeba (a microscopic unicellular organism from the category of protozoa).

The main functions of leukocytes

Despite the similarity of leukocytes with amoebas, they perform the most complex functions. Their main task is to protect the body from various viruses and bacteria, destruction of malignant cells. Leukocytes chase bacteria, envelop them and destroy them. This process is called phagocytosis, which in Latin means "devouring something by cells." Destroying the virus is more difficult. When sick, viruses settle inside the cells of the human body. Therefore, in order to get to them, leukocytes need to destroy cells with viruses. Leukocytes also destroy malignant cells.

Where are leukocytes formed and how long do they live?

In the performance of their functions, many leukocytes die, so the body constantly reproduces them. Leukocytes are formed in the organs that make up the human immune system: in the bone marrow, lymph nodes, tonsils, spleen and in the lymphoid formations of the intestine (in Peyer's patches). These organs are located in different places in the body. it is also a place where leukocytes, platelets, erythrocytes are formed. It is believed that leukocytes live for about 12 days. However, some of them die very quickly, which happens when they fight with a large number of aggressive bacteria. Dead white blood cells can be seen if pus appears, which is their accumulation. In place of them, from the organs related to the immune system, where leukocytes are formed, new cells come out and continue to destroy bacteria.

Along with this, among T-lymphocytes there are immunological memory cells that live for decades. A lymphocyte met, for example, with such a monster as the Ebola virus - he will remember it for the rest of his life. When re-encountered with this virus, lymphocytes are transformed into large lymphoblasts, which have the ability to multiply rapidly. Then they turn into killer lymphocytes (killer cells), which block access to the body of a familiar dangerous virus. This indicates the presence of immunity to this disease.

How do leukocytes learn about the introduction of a virus into the body?

In the cells of each person there is an interferon system, which is part of innate immunity. When a virus enters the body, interferon is produced - a protein substance that protects cells that have not yet been infected from the penetration of viruses into them. At the same time, interferon is one of the types of leukocytes. From the bone marrow, where white blood cells are formed, they travel to infected cells and destroy them. At the same time, some viruses and their fragments fall out of the destroyed cells. Dropped viruses try to penetrate into cells that are not yet infected, but interferon protects these cells from their introduction. Viruses outside of cells are not viable and die quickly.

The fight of viruses with the interferon system

In the process of evolution, viruses have learned to suppress the interferon system, which is too dangerous for them. Influenza viruses have a strong suppressive effect on it. Even more depresses this system However, the Ebola virus broke all records, which practically blocks the interferon system, leaving the body practically defenseless against a huge number of viruses and bacteria. From the spleen, lymph nodes and other organs related to the immune system, where leukocytes are formed, more and more new cells come out. But, having not received a signal about the destruction of the virus, they are inactive. In this case, the human body begins to decompose alive, many toxic substances are formed, blood vessels are torn, and the person bleeds. Death usually occurs in the second week of illness.

When does immunity occur?

If a person has been ill with one or another disease and recovered, then he develops a stable acquired immunity, which is provided by leukocytes belonging to the groups of T-lymphocytes and B-lymphocytes. These white blood cells are formed in the bone marrow from progenitor cells. Acquired immunity develops after vaccination. These lymphocytes are well aware of the virus that has been in the body, so their killing effect is targeted. The virus is practically unable to overcome this powerful barrier.

How do killer lymphocytes kill cells that have become dangerous?

Before you kill a dangerous cell, you need to find it. Killer lymphocytes tirelessly search for these cells. They are guided by the so-called histocompatibility antigens (tissue compatibility antigens) located on cell membranes. The fact is that if a virus enters the cell, then this cell dooms itself to death to save the body and, as it were, throws out a “black flag”, signaling the introduction of the virus into it. This "black flag" is information about the introduced virus, which, in the form of a group of molecules, is located next to the histocompatibility antigens. The killer lymphocyte "sees" this information. He acquires this ability after training in the thymus gland. Control over learning outcomes is very tight. If a lymphocyte has not learned to distinguish a healthy cell from a diseased one, it will inevitably be destroyed. With such a strict approach, only about 2% of killer lymphocytes survive, which later exit the thymus gland to protect the body from dangerous cells. When the lymphocyte determines for sure that the cell is infected, it gives it a "lethal injection" and the cell dies.

Thus, leukocytes play a huge role in protecting the body from disease-causing agents and malignant cells. These are small tireless warriors of the body's main defenses - the interferon and immunity systems. They die en masse in the struggle, but from the spleen, lymph nodes, bone marrow, tonsils and other organs of the immune system, where leukocytes are formed in humans, they are replaced by many newly formed cells, ready, like their predecessors, to sacrifice their lives in the name of saving the human body. Leukocytes ensure our survival in an external environment filled with a huge number of different bacteria and viruses.

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In this part, we are talking about the types of leukocytes and their number, about the structure and functions. various kinds leukocytes: neutrophils, eosinophils, basophils, lymphocytes, monocytes

Leukocytes.

Types of leukocytes, their number.

Leukocytes called white blood cells. They are divided into two large groups: granular leukocytes, or granulocytes, And non-granular, agranulocytes. Granular leukocytes got their name due to the presence of characteristic granularity in their cytoplasm.

Depending on the ability to perceive certain dyes, granulocytes are divided into neutrophils, eosinophils and basophils. Neutrophils make up 60-70% of milestone whites blood cells, eosinophils - 1-4%, basophils - 0-0.5%.

Agranulocytes are represented lymphocytes and monocytes. Lymphocytes make up 25-30% of all leukocytes, monocytes - 6-8%. In total, 1 mm 3 of blood contains 6000-8000 leukocytes. An increase in their number in the blood is called leukocytosis. It is noted in acute infectious diseases, inflammatory processes, with various intoxications, after eating. A decrease in the number of white blood cells is called leukopenia. It can be observed with oppression of bone marrow function.

The structure and functions of various types of leukocytes.

Neutrophils have a rounded shape, their diameter is 12 microns. The cytoplasm in the stained preparation is pink, its granules are stained bluish-pink. The composition of the granularity includes a variety of enzymes that provide the synthesis and breakdown of substances, amino acids, glycogen, lipids, RNA. The nucleus usually consists of 3-4 segments. The nuclei have processes - nuclear appendages.

Neutrophils have a pronounced ability to phagocytosis. Phagocytosis is the ability of a cell to capture and digest a wide variety of substances (microbes, paint, cell fragments, etc.).

The phenomenon of phagocytosis was discovered by I.I. Mechnikov, who showed that mobile cells - leukocytes - are capable of capturing and digesting solid particles, due to which they perform a protective function in the body. Cells capable of capturing and digesting foreign substances were named by him. phagocytes, which means "cell eaters".

Mechnikov identified the main phases of phagocytosis: convergence phagocyte with an object, attraction, which is understood absorption And digestion. The approach of phagocytes to the object is possible because they are capable of locomotion. Neutrophils are characterized by amoeboid movement. At the end of the cell, opposite to the direction of movement, a pseudopodium appears. It increases in size, and the cytoplasm moves into it. The speed of movement of human neutrophils is on average 28 microns/min. The speed of movement depends on the temperature of the medium. The maximum speed is noted at a temperature of 38-39 degrees. The speed also depends on various substances contained in plasma and tissues exposed to damaging effects. For the implementation of motor activity, energy is needed, which ATP delivers. In neutrophils, ATP resynthesis can also occur in an anoxic environment, i.e. under anaerobic conditions, due to the fact that the process of glucose breakdown, which provides energy for this resynthesis, can occur anaerobically in them. Mechnikov developed the theory of inflammation, according to which inflammation should be considered as a protective reaction of the body, aimed at combating a harmful agent. Leukocytes-phagocytes, accumulating in the focus of inflammation, contribute to its elimination. One leukocyte can capture 15-20 microbes. Wherein a large number of leukocytes die in the focus of inflammation. This theory of Mechnikov was later confirmed. It is now known that the intensity of phagocytosis depends on the activity of antibodies and the properdin system, on the presence of vitamins, and on the influence of nervous and humoral factors. Inhibit phagocytosis acetylcholine, glucocorticoids.

Neutrophils are short-lived: their life span is 8-12 days. In addition to phagocytic neutrophils, they also perform a transport function. They carry antibodies by adsorbing them on their surface. Neutrophils also enhance miotic activity, contributing to the restoration - regeneration - of damaged tissues.

Eosinophils have a diameter of 12-15 microns. Their cytoplasm contains granules of spherical or oval shape tinted yellow-pink. The rest of the cytoplasm is stained blue. Granules contain enzymes, but they lack glycogen.

The core consists of two segments. Eosinophils have weak phagocytic activity. Their main function is to inactivate histamine, which is formed especially in large quantities in diseases associated with increased sensitivity to foreign elements. Eosinophils contain an enzyme that breaks down histamine. In addition, adsorbing the latter, they carry it to the lungs and intestines, where it is excreted. It is clear that in the case of increased formation of histamine in the body, the number of eosinophils increases.

Basophils- cells with a diameter of 10 microns. The granules of their cytoplasm are stained dark purple. They contain RNA, glycogen, enzymes, heparin, histamine. The cytoplasm is stained pink. The nucleus is clawed. The main function of basophils is the synthesis of histamine, heparin. Half of the histamine in the blood is found in basophils.

Lymphocytes depending on their size, they are divided into three groups: large (15-18 microns), medium (10-14 microns) and small (6-9 microns). Most of all in the blood of small lymphocytes. The shape of lymphocytes is round or oval. Their core turns dark blue. It occupies almost the entire cell.

The cytoplasm is stained with basic paints. It contains enzymes, nucleic acids, ATP. Glycogen is not present in all lymphocytes. The function of lymphocytes is associated with the production of beta and gamma globulins. The more RNA the cytoplasm contains, the more pronounced its ability to produce antibodies. Like neutrophils, lymphocytes can adsorb antibodies and transport them to the site of inflammation. Lymphocytes neutralize various toxins.

Monocytes are the largest blood cells. Their diameter reaches 13-25 microns. The core is irregular, oval or bean-shaped, with impressions and extensions. The cytoplasm stains bluish-gray or gray-blue. The cytoplasm contains RNA, polysaccharides and enzymes. Monocytes have a greater ability to amoeboid movement than lymphocytes, and therefore they are characterized by a phagocytic function. It is carried out, unlike neutrophils, and in an acidic environment. Therefore, monocytes are actively involved in the fight against infection in the foci of inflammation.

The platelet is made up of:

1) Hyalomer - represents the basis of the platelet;

2) Granulomere - grains that form an accumulation in the center or scattered around the periphery.

There are two types of granules:

a) dense, dark (- granules)

b) serotonin granules (δ-granules)

c) lysosomes and microperoxisomes (λ-granules).

Granulomere also contains grains of glycogen and mitochondria.

The hyalomere contains circularly arranged bundles of 10 to 15 microtubules that help maintain the shape of the platelet as well as actin and myosin microfilaments.

Platelets form a large number of processes of various sizes and thicknesses (antennae), which are involved in platelet aggregation and thrombus formation.

When stained according to the Romanovsky-Giemsa method, it is found 5 types of platelets:

A) young with basophilic hyalomer and single azurophilic granules;

b) mature , with weakly oxyphilic hyalomer and pronounced azurophilic granularity;

V) old - dark; blue - violet hue with dark - violet granularity;

G) degenerative with grayish - bluish hyalomer and bluish - violet granularity;

e) giant shapes (forms of irritation), the size of which is 2 to 3 times the normal size. They have a pinkish - lilac hyalomer with purple granularity.

The lifespan of a platelet is 5-8 days.

¨Function - participation in blood coagulation. Platelets secrete the enzyme thromboplastin, which promotes the conversion of soluble fibrinogen into insoluble fibrin. Aggregated platelets form the framework of a thrombus, on which fibrin strands settle.

Thrombocytopenia leads to decreased blood clotting and is accompanied by spontaneous bleeding.

Leukocytes - white, spherical, containing a nucleus and all cytoplasmic organelles of blood cells that are able to go beyond the vessels and actively move through the formation of pseudopodia.

In an adult, the number of leukocytes in 1 liter of blood is 3.8 x 10 9 - 9x10 9.

An increase in the number of leukocytes - leukocytosis; decrease - leukopenia;

classification

All leukocytes, depending on the presence of granularity or lack thereof, are divided into:

1. Granulocytes- granular;

2. Agranulocytes- not containing granularity;

Depending on the grain color granulocytes are divided into:

1) neutrophilic: a) young; b) stab c) segmented

2) oxyphilic (acidophilic, eosinophilic),

3) basophilic.

Agranulocytes are divided into: 1) lymphocytes; 2) monocytes;

The structure of leukocytes

I Granulocytes. Neutrophil

¨The number of 65-70% of the total number of leukocytes; the diameter in a fresh drop of blood is 7-9 microns, in a smear 10-12 microns.

¨Cytoplasm of neutrophils contains fine granularity. The number of granules in each cell can be from 50 to 200. Granularity does not occupy the entire cytoplasm - the surface layer in the form of a narrow border remains homogeneous and contains thin filaments. This layer plays a major role in the amoeboid movement of the cell, participating in the formation of pseudopodia.

¨Depending on the structure and chemical composition, two main types of granules are distinguished:

1) azurophilic - nonspecific;

2) neutrophilic - specific;

Azurophilic granules- appear earlier in the development of the neutrophil and therefore they are called primary. There are more of them in unspecialized cells and in the process of specialization (differentiation) their number decreases, and in mature cells it is 10-20%. Sizes from 0.4 to 0.8 µm. These granules represent a variety of lysosomes, as evidenced by the presence in them of hydrolytic enzymes typical of lysosomes (acid phosphatase), they have a round or oval shape.

Neutrophil granules- appear in the process of neutrophil development; they are called secondary, their number increases in the process of cell specialization. In a mature neutrophil, they make up 80-90% of the total number of granules. Mature neutrophilic granules are 0.1-0.3 μm in diameter, round or oval, sometimes filiform. Mature granules are large (0.2-0.4) µm. They contain alkaline phosphatase, basic cationic proteins, phagocytins, lactoferrin, lysozyme, aminopeptidases.

¨In the cytoplasm, organelles are poorly developed, few mitochondria, a small Golgi complex, sometimes there are reduced elements of the endoplasmic reticulum; inclusions of glycogen, lipids, etc. are characteristic. When stained according to Romanovsky-Giemsa, the granularity is pink-violet.

The nuclei of neutrophilic leukocytes contain dense chromatin, especially along the periphery, in which it is difficult to distinguish the nucleoli. The shape of the nuclei is not the same, therefore they are also called polymorphonuclear, mature ones have segmented nuclei, consisting of 2-3 or more lobules, connected by very thin, sometimes imperceptible, jumpers. These are segmented neutrophils.. Their overwhelming number is 49-72%.

Less contained stab 1-6% of the nuclei of these cells have the shape of the letter S or horseshoe.

Young Neutrophilic granulocytes are even rarer 0-0.5% with bean-shaped nuclei.

Neutrophil granulocytes are motile cells, they can migrate from blood vessels and move to the source of irritation and have a high ability to phagocytosis .

Neutrophils produce chalons - specific substances that inhibit DNA synthesis in granulocytic cells and have a regulatory effect on the processes of proliferation and differentiation of leukocytes. Life expectancy is about 8 days, they are in the bloodstream for 8-12 hours, and then they go into the connective tissue, where their maximum functional activity is manifested.

II Eosinophilic(acidophilic, oxyphilic) granulocytes. Eosinophils.

¨Their diameter in a drop of fresh blood is from 9 to 1 microns, and in a smear 12-14 microns. The amount is 1-5% of the total number of leukocytes.

¨Cytoplasm contains two types of granules:

1) the first type (oxyphilic) - oval or polygonal shape, about 0.5-1.5 microns in size. Oxyphilicity is due to the content in them of the main protein, rich in amino acids - arginine. The granules contain most of the hydrolytic enzymes.

2) the second type of granules of smaller sizes 0.1-0.5 μm, round shape, homogeneous or granular ultrastructure. They contain acid phosphatase and arylsulfatase.

There are three types of eosinophils:

a) segmented; b) stab; c) young;

The nucleus of segmented eosinophils, as a rule, consists of two segments (rarely three), interconnected by thin bridges. Occasionally there are stab and young forms, similar to neutrophils of the corresponding stages. The nuclei of eosinophils are composed mainly of heterochromatin, the nucleoli are not visible. They are less mobile than neutrophils.

Functions. Eosinophils are involved in the body's defense response to foreign protein, in allergic and anaphylactic reactions. They are able to phagocytize and inactivate histamine with the help of the histaminase enzyme, as well as adsorb it on their surface. The number of eosinophils in the peripheral blood increases with helminthiases, allergic reactions.

Eosinophils are capable of phagocytosis, but their activity is lower than that of neutrophils.

III. Basophilic have a diameter of about 9 microns in a drop of fresh blood and about 11-12 microns in a smear. In human blood, they make up 0.5-1% of the total number of leukocytes.

¨Cytoplasm contains large, round or polygonal, basophilic granules, the diameter of which varies from 0.5 to 1.2 microns.

Granules have metachromasia, which is due to the presence in them of acidic glycosaminoglycan- heparin. Metachromasia is the property of changing the original color of the dye. In addition to heparin, the granules contain histamine.

The granules are heterogeneous in density, which reflects their different degree of maturity and functional state. In addition to specific basophilic granules, basophils also contain azurophilic nonspecific granules, which are lysosomes. There are all kinds of organelles in the cytoplasm.

The nucleus of basophils is often weakly lobular, less often spherical, stains much less intensely than the nuclei of neutrophils or eosinophils.

¨ Functions basophils are determined by their ability to metabolize histamine and heparin. They are involved in the regulation of blood coagulation (heparin - anticoagulant) and vascular permeability (histamine). Participate in the immunological reactions of the body, in particular allergic nature. Due to the presence of antibody receptors (IgE) on their surface, they are able to react to the antigen-antibody complex, which leads to the release of histamine. Histamine, having the ability to dilate blood vessels, increase the permeability of the vascular wall and intercellular substance, irritate nerve endings, causes a complex of symptoms of an allergic reaction (hyperemia, swelling, itching, etc.). In addition, histamine causes spasm of bronchial smooth muscle cells, participating in the pathogenesis of bronchial asthma. Simultaneously with histamine, basophils secrete an eosinophil attraction factor. The latter are involved in the inactivation of histamine, thereby stopping allergic manifestations.

The phagocytic activity of basophils is negligible.

Lymphocytes - make up 19-37% of the total number of leukocytes, the sizes vary significantly from 4.5 to 10 microns, and therefore they are distinguished:

a) small - with a diameter of 4.5-6.0 microns;

b) medium - with a diameter of 7-10 microns;

c) large - with a diameter of 10 microns or more;

Lymphocytes have an intensely stained round or bean-shaped nucleus and a relatively small rim of basophilic cytoplasm. The cytoplasm of some lymphocytes has a small amount of azurophilic granules (lysosomes).

Electron-microscopically, 4 types of cells were found and isolated in adults: 1) small light cells; 2) small dark; 3) medium; 4) plasmocytes (lymphoplasmocytes);

small light lymphocytes- diameter is about 7 microns, nuclear - cytoplasmic balance is shifted towards the nucleus. The nucleus is rounded, chromatin is condensed along the periphery.

The cytoplasm contains a small number of ribosomes and polysomes, elements of the granular endoplasmic reticulum, centrosomes, the Golgi complex, mitochondria, many vacuoles and multivesicular bodies are poorly expressed, lysosomes are found. Organelles are usually located near the nucleus. The number of these lymphocytes is 70-75% of the total.

Small dark lymphocytes- diameter 6-7 microns. The nuclear-cytoplasmic ratio is even more shifted in favor of the nucleus. The chromatin looks dense, the nucleolus is large.

The cytoplasm surrounds the nucleus with a narrow rim, has a high density (dark), contains a large number of ribosomes, few mitochondria, and their light matrix stands out against the dark background of the cytoplasm. Other organelles are rare. The number is about 12-13% of all lymphocytes.

Medium lymphocytes- diameter is about 10 microns. The nucleus is bean-shaped or rounded, finger-like protrusions of the nuclear membrane are often visible. The chromatin in the nucleus is looser, areas of condensed chromatin are visible near the nuclear envelope, and the nucleolus is well defined.

The cytoplasm contains elongated tubules of the granular endoplasmic reticulum, free ribosomes and polysomes. The centrosome and the Golgi complex are usually located near the area of ​​invagination of the nuclear membrane, there are fewer mitochondria. Lysosomes are found in small numbers. The amount is 10-12% of all lymphocytes.

Plasma cells(lymphoplasmocytes). A characteristic feature of these cells is the concentric arrangement around the nucleus of the tubules of the granular endoplasmic reticulum. Their number is 1-2%.

Among lymphocytes, according to the ways of development and differentiation, their role in protective reactions, two main types are distinguished:

1. T - lymphocytes; 2. B - lymphocytes;

T - lymphocytes (thymus dependent) - are formed from bone marrow stem cells in the thymus and provide cellular immune responses and regulation of humoral immunity. These are lymphocytes - centenarians, they can live for several (even several tens) years. They make up 80% of all lymphocytes in the peripheral blood.

In a population of T - lymphocytes, there are:

1. Cytotoxic T - lymphocytes (killers);

Regulatory effect on B-lymphocytes

a) T - helpers

b) T - suppressors

T - killers are effector cells of cellular immunity, a specific cytotoxic effect, which provides antitumor and transplantation immunity.

T helpers (helpers)) are able to specifically recognize the antigen and enhance the formation of antibodies.

T - suppressors (oppressive) able to suppress the ability of B-lymphocytes to participate in the production of antibodies by B-lymphocytes. This action is carried out with the help of special soluble substances - lymphokines that are produced by the action of antigens.

B-lymphocytes are formed from bone marrow stem cells in the Fabricius bag (bursa Fabricius) in birds, in humans in the embryonic period in the liver, in adults - in the bone marrow.

There were no clear morphological differences between T- and B-lymphocytes. In B-lymphocytes, the granular endoplasmic reticulum is more pronounced and developed, and in T-lymphocytes, lysosomes are more numerous. T-lymphocytes have smaller sizes and smaller nuclei, a higher content of heterochromatin.

B-lymphocyte membranes have a variety of surface receptors to antigen, which determine the heterogeneity of B-cell populations. Each lymphocyte differs in the specificity and class of its surface immunoglobulin.

¨Function - ensuring humoral immunity by producing antibodies (immunoglobulins).

The effector cell is the plasma cell.

Monocytes. In a drop of fresh blood, the size of monocytes is 9-12 microns, in a blood smear 18-20 microns. Monocytes belong to the macrophage system of the body, to the so-called mononuclear phagocytic system - whose cells originate from promonocytes of the bone marrow and in the circulating blood represent a pool of relatively immature cells that are on the way from the bone marrow to the tissue (time in the blood from 36 to 104 hours).

The cytoplasm is less basophilic than the cytoplasm of lymphocytes. When stained according to Romanovsky-Giemsa, it has a pale blue color, along the periphery it stains somewhat darker than near the nucleus, contains a different number of very small azurophilic grains (lysosomes). It has finger-like outgrowths, phagocytic vacuoles, numerous pinocytic vesicles, short tubules of the granular endoplasmic reticulum, and small mitochondria.

¨The nuclei of monocytes are of various shapes: bean-shaped, horseshoe-shaped, rarely lobed, with numerous protrusions and depressions. Chromatin in the form of small grains is located throughout the nucleus. Has one or more nucleoli.

The number of monocytes in the blood ranges from 3-11%.

Function. Having left the vascular bed into the tissue, the monocyte differentiates into a macrophage and performs specific functions.

Lymph (lat.limpha- moisture) - a yellowish liquid, of a protein nature, flowing in the lymphatic vessels. Comprises lymphoplasm and formed elements.

Lymphoplasma similar in composition to blood plasma, but contains less protein. The amount of albumins is greater than that of globulins. Part of the protein is enzymes: diastase, lipase and glycolytic enzymes. Contains neutral fats simple sugars, NaCl, Na 2 CO 3 , as well as compounds that include calcium, magnesium, iron.

Shaped elements- These are mainly lymphocytes (98%), as well as monocytes.

Distinguish:

1. Peripheral lymph - from tissues to lymph nodes;

2. Intermediate - after passing through the lymph nodes;

3. Central - lymph of the thoracic and right lymphatic ducts.

Lymph is formed in the lymphatic capillaries of tissues and organs, where, under the influence of various factors, in particular osmotic and hydrostatic pressure, various components of the lymphoplasm constantly flow from the tissues.

The number of leukocytes - important indicator for the diagnosis of pathological conditions. In the body, leukocytes are constantly produced, and their content in the blood can vary throughout the day. How are these cells produced and what role do they play in the human body?

Several types of formed elements float in the blood, which maintain the health of the whole organism. White cells that have a nucleus inside are called leukocytes. Their feature is the ability to penetrate through the wall of capillaries and enter the intercellular space. It is there that they find foreign particles and absorb them, normalizing the vital activity of the cells of the human body.

Leukocytes include several types of cells that differ slightly in origin and appearance. The most popular is their division according to morphological features.

The ratio of these cells is the same in all healthy people and is expressed by the leukocyte formula. By changing the number of any type of cells, doctors draw conclusions about the nature of the pathological process.

Important: it is leukocytes that maintain human health at the proper level. Most infections that enter the human body are asymptomatic due to a timely immune response.

The importance of leukocytes is explained by their participation in the immune response and the protection of the body from the ingress of any foreign agents. The main functions of white cells are as follows:

1. Production of antibodies.
2. Absorption of foreign particles - phagocytosis.
3. Destruction and removal of toxins.

Each type of leukocyte is responsible for certain processes that help in the implementation of the main functions:

1. Eosinophils. They are considered the main agents for the destruction of allergens. Participate in the neutralization of many foreign components that have a protein structure.
2. Basophils. They accelerate the healing process in the focus of inflammation, due to the presence of heparin in its structure. Updated every 12 hours.
3. Neutrophils. Participate directly in phagocytosis. They are able to penetrate into the intercellular fluid and into the cell where the microbe lives. One such immune cell can digest up to 20 bacteria. Fighting microbes, the neutrophil dies. Acute inflammation provoke a sharp production of such cells by the body, which is immediately reflected in the leukocyte formula as an increased amount.
4. Monocytes. Help neutrophils. They are more active if an acidic environment develops in the focus of inflammation.
5. Lymphocytes. Distinguish own cells from strangers in structure, participate in the production of antibodies. Live for several years. Are the most important component immune protection.

Important: many doctors before prescribing treatment are forced to do clinical analysis blood. Viral and bacterial diseases cause different changes in the analysis, which makes it possible to put correct diagnosis and prescribe the necessary drugs.

All types of white blood cells are produced in the bone marrow, which is found inside the bones. It contains a huge number of immature cells, similar to those that an embryo has. Of these, as a result of a complex multi-stage process, various hematopoietic cells are formed, including all types of leukocytes.

The transformation occurs as a result of the division of immature cells. With each stage, they become more differentiated and designed to perform more specific functions. All stages, and there can be up to 9 of them, occur in the bone marrow. The exception is lymphocytes. For full "growing up" they will need to mature in the lymphoid organs.

Leukocytes accumulate in the bone marrow, and during the inflammatory process they enter the bloodstream and reach the pathological focus. After fulfilling their purpose, the cells die, and the bone marrow forms new ones. Normally, only a small part of all leukocyte reserves of the body floats in the bloodstream (up to 2%).

In the inflammatory process, all cells rush to the place of its localization. Stocks of neutrophils for such emergency surges are located on the walls of blood vessels. It is this depot that allows the body to quickly respond to inflammation.

Lymphocytes can mature into T or B cells. The former regulate the production of antibodies, while the latter recognize foreign agents and neutralize them. The intermediate development of T cells occurs in the thymus. The final maturation of lymphocytes occurs in the spleen and lymph nodes. It is there that they actively share and turn into a full-fledged immune defense. With inflammation, lymphocytes move to the nearest lymph node.

Important: The mechanism of formation of leukocytes is very complex. Do not forget about the importance of the spleen and other organs. For example, drinking alcohol has a negative effect on them.

Video - Leukocytes

Lack of white blood cells

Leukopenia in an adult is called a condition when the number of leukocytes is below 4 * 10 9 / l. This may be caused malignant diseases, exposure to radiation, vitamin deficiencies, or problems with hematopoietic function.

Leukopenia leads to the rapid development of various infections, a decrease in the body's resistance. A person feels chills, body temperature rises, there is a breakdown and exhaustion. The body tries to compensate for the lack of defense cells, resulting in an enlarged spleen. This condition is very dangerous and requires mandatory identification of the cause and treatment.

Important: chronic fatigue or other conditions that bother you for a long time should not be ignored. Often they occur due to a decrease in the body's defenses.

Excess white blood cells

The number of leukocytes above 9 * 10 9 / l is considered to be in excess of the norm and is called leukocytosis. Physiological enlargement, which does not require treatment, may be caused by eating, physical activity, some hormonal surges (pregnancy, premenstrual period).

The following causes of leukocytosis lead to pathological conditions:

1. Infectious diseases.
2. Inflammatory processes of microbial and non-microbial etiology.
3. Blood loss.
4. Burns.

Treatment for this condition may include following groups drugs:

1. Antibiotics. Help to eliminate the infection that caused leukocytosis and prevent complications.
2. Steroid hormones. They quickly and effectively relieve inflammation, which leads to a decrease in the production of leukocytes.
3. Antihistamines. They also help reduce inflammation.

The tactics of treating any changes in the leukocyte formula depends on the cause that caused them.

Important: slight changes in the leukocyte formula may be temporary and even considered normal. Strong discrepancies with acceptable values ​​or the absence of changes during repeated analyzes should alert.

The importance of white blood cells is taught to children at school. This topic is not an exaggeration. Good immunity ensures the health and good quality of life of every person. To determine the state of the immune system, you can take a blood test in the absence of diseases. A competent doctor will help to interpret the results correctly.

Video - What does an increase in leukocytes in a blood test mean?