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White blood cells

White blood cells are white (colorless) blood cells. Leukocytes are nuclear cells measuring 7-20 microns. At rest, white blood cells are round, but they have amoeboid movements; they are able to penetrate through the walls of blood vessels and exit from the bloodstream. The normal content of leukocytes in the blood ranges from 4000-5000 to 8000-9000 in 1 mm 3 .

Distinguish leucocytes are granular, or granulocytes (contain specific granularity in the cytoplasm), and non-grained, or agranulocytes (Fig. 2). Depending on the nature of the granularity during coloration according to Romanovsky - Giemsa granulocytes are divided into neutrophilic, eosinophilic and basophilic. Neutrophilic leukocytes have a fine granular brownish-purple color. Eosinophilic leukocytes with abundant large orange-red grit and basophilic with large dark purple grains of various sizes. The cytoplasm of granulocytes is colored pink, the nuclei of their irregular shape, sometimes in the form of a bent tow (band), often divided into segments, connected by thin jumpers (segmented).

Agranulocytes (lymphocytes and monocytes) differ in basophilic (blue) cytoplasm and non-segmented nucleus. Compared with the lymphocyte (see), the monocyte has a larger size (12–20 microns), a light-colored nucleus of an irregular (usually horseshoe-shaped) shape, a smoky blue cytoplasm, sometimes with a dusty red granularity. In blood diseases, in addition to the listed mature forms of white blood cells, immature forms (myelocytes, metamyelocytes), undifferentiated and plasma cells may appear. The latter have an eccentrically located round nucleus and a blue vacuolated cytoplasm, which is clarified to the nucleus. Leukocytes have a number of important functions, in particular in the protection of the body (see Antibodies, Phagocytosis ), in wound healing, interstitial metabolism, etc.

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See also Blood formation , Leukocytic formula .

white blood cells
Fig. 2. Leukocytes (staining according to Romanovsky - Giemsa): 1 - neutrophilic myelocytes; 2 - neutrophilic metamyelocytes (young); 3 - stab neutrophils; 4 - segmented neutrophils; 5 - eosinophils; 6 - basophils; 7 - lymphocytes; 8 - monocytes; 9 - plasma cells; 10 - neutrophil with toxic granularity.

White blood cells (from the Greek. Leukos - white and kytos - cell) - white blood cells, one of the types of blood cells. Leukocytes are a rounded cell with a nucleus and homogeneous or granular protoplasm. In human blood, there are granular leukocytes - granulocytes and non-granular leukocytes - agranulocytes. The granulocytes include leukocytes with neutrophilic, eosinophilic and basophilic granularity, agranulocytes are lymphocytes (see) and monocytes. Neutrophilic leukocytes - neutrophils - cells with a diameter of about 12 microns. Protoplasm of them is colored according to the method of Romanovsky - Giemsa in pink color, i.e. it is oxyphilic, and grains - in violet color (neutrophilic granularity). The nucleus is rich in chromatin, polymorphic; in young cells of a bean-shaped or sausage-shaped (young), in others, elongated in the form of sticks, horseshoes (band-core) and in the most mature ones, constricted into individual segments (segmented). Constriction may sometimes be invisible, which led some authors to take segments as separate nuclei and call such cells polynuclears, in contrast to mononuclear cells — large mononuclear cells of a lymphoid character with azurophilic granularity. Such an opposition should be considered wrong, since all leukocytes are essentially mononuclear cells. Currently, instead of "polynuclear", the name "segmented nucleus" leukocyte is generally accepted. "Young" neutrophils in normal blood usually do not occur. Their appearance speaks of a regenerative shift - a nuclear shift "to the left" (see Leukocyte formula).

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An increase in the number of cells with a segmented nucleus is a “right” shift. In some inflammatory and infectious diseases (pneumonia, sepsis, purulent processes), the grains in the protoplasm of neutrophils are coarser, unequal in size, unevenly colored, which is commonly called toxic (toxigenic) neutrophil granularity. In this case, a nuclear shift is usually observed. Often, along with toxic granularity in the protoplasm of neutrophils, there are the so-called Dela bodies (more precisely - Knyazkova-Del) - pale blue lumps of various shapes.

Eosinophilic leukocytes - eosinophils - with a diameter of about 12 microns. Their protoplasm is weakly basophilic, is colored in a bluish color, and the grain in it is well colored by eosin in a bright pink color. The nucleus is less lobed than the neutrophil, usually consists of two segments. Basophilic leukocytes — basophils — are about 8 to 10 microns in diameter with an oxyphilic protoplasm that stains pink. The grains are large, of various sizes, stained in metachromatic with the basic colors in a dark purple color. The core consists of 3-4 segments and resembles a maple leaf.

Monocyte is the largest normal blood cell with a diameter of 12-20 microns. The nucleus is often located eccentrically, oval or horseshoe-shaped, has a wide-mesh chromatin network, is painted in red-violet color. Protoplasm is colored dark gray with a bluish tinge. Sometimes it is possible to note fine azurophilic granularity in the protoplasm.

Leukocyte physiology. One of the main functions of leukocytes is to protect the body from germs and foreign substances that enter the blood or tissues (the function of cleansing, neutralization). An important property of leukocytes is their ability to amoeboid movement, especially characteristic of granular leukocytes and monocytes. Leukocytes have the ability to pass through the vessel wall into the surrounding connective tissue and back into the vessel. Leukocytes, especially mature neutrophils, are characterized by the function of phagocytosis (see) and participation in the processes of immunity. Leukocytes stimulate regeneration processes, activate wound healing. Leukocytes are secreted with the secretion of glands in the digestive tract, with products of inflammation, quickly collapsing. The lifetime of leukocytes is small - 2-4-10 days. Leukocytes have significant secretory ability (secretion of alexins, bactericidal substances such as lysozyme), sero-immunological activity (the formation of antibodies - leukocytolysins, leukoagglutininov), are involved in the processes of interstitial metabolism. Leukocytes have a pronounced enzymatic activity, they found various enzymes: oxidase, amylase, catalase, lipase, phosphatase. Eosinophils are mainly attributed to the detoxification function, their number increases with allergic conditions, helminthiases, skin diseases and decreases at the height of infectious diseases, with poisoning. The function of basophils has been little studied, indicating their participation in the formation of heparin and histamine. Monocytes possess a phagocytic ability. Leucocyte sedimentation is a phenomenon analogous to erythrocyte sedimentation (see).

Due to the complexity of the determination and inconstancy of the results obtained, the determination of the speed of sedimentation of leukocytes was not included in clinical practice.