The main sphere of action of leukocytes is protection. They play a major role in the specific and nonspecific protection of the body from external and internal pathogenic agents, as well as in the implementation of typical pathological processes.
All types of leukocytes are capable of active movement and can pass through the capillary wall and penetrate into the intercellular space, where they absorb and digest foreign particles. This process is called phagocytosis, and the cells that carry it out are phagocytes.
If a lot of foreign bodies have penetrated into the body, then phagocytes, absorbing them, greatly increase in size and eventually are destroyed. At the same time, substances are released that cause a local inflammatory reaction, which is accompanied by edema, fever and redness of the affected area.
Substances that cause an inflammatory reaction attract new leukocytes to the site of introduction of foreign bodies. Destroying foreign bodies and damaged cells, leukocytes die in large numbers. The pus that forms in the tissues during inflammation is a collection of dead white blood cells.
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In the blood of an adult, leukocytes are 1000 times less than erythrocytes, and on average their number is 4-9⋅10 9 /. In newborn children, especially in the first days of life, the number of leukocytes can vary greatly from 9 to 30⋅10 9 /. In children aged 1-3 years, the number of leukocytes in the blood ranges from 6.0-17.0⋅10 9 /, and at 6-10 years old, within 6.0-11.0⋅10 9 /.
An increase in the total absolute number of leukocytes per unit volume above the upper limit of the norm is called absolute leukocytosis, and decreasing it below the lower border - absolute leukopenia.
Leukocytosis
True leukocytosis occurs with an increase in the formation of leukocytes and their release from the bone marrow. If an increase in the content of leukocytes in the blood is associated with the entry into circulation of those cells that are normally attached to the inner surface of the vessels, such leukocytosis is called redistributive.
It is the redistribution of leukocytes that explains the fluctuations during the day. So, the number of leukocytes usually rises somewhat in the evening, as well as after eating.
Physiological leukocytosis observed in the premenstrual period, in the second half of pregnancy, 1-2 weeks after delivery.
Physiological redistributive leukocytosis can be observed after eating, after physical or emotional stress, exposure to cold or heat.
Leukocytosis as a pathological reaction most often indicates an infectious or aseptic inflammatory process in the body. In addition, leukocytosis is often detected in poisoning with nitrobenzene, aniline, in the initial phase of radiation sickness, as a side effect of certain medications, as well as in malignant neoplasms, acute blood loss and many other pathological processes. In the most severe form, leukocytosis is manifested in leukemia.
Leukopenia
Leukopenia can also be physiological (constitutional leukopenia) and pathological, redistributive and true.
Some Causes of Leukopenia:
- chronic infections: tuberculosis, HIV;
- hypersplenism syndrome;
- aplastic conditions of the bone marrow;
Types of leukocytes
Leukocytes are a collective concept introduced in the 19th century and retained for simplicity of the opposition "white blood - red blood". According to modern data, leukocytes differ in origin, function and appearance. Some leukocytes are capable of capturing and digesting foreign microorganisms (phagocytosis), while others can produce antibodies. As a result, there are several types of leukocyte division, the simplest of which is based on the presence / absence of specific granules in their cytoplasm.
According to morphological characteristics, leukocytes stained according to Romanovsky - Giemsa have traditionally been divided into two groups since the time of Ehrlich:- granular white blood cells, or granulocytes- cells with large segmented nuclei and exhibiting specific granularity of the cytoplasm; depending on the ability to perceive dyes, they are divided into
Leukocytes are white (colorless) blood cells. Leukocytes are nuclear cells 7-20 microns in size. At rest, leukocytes are round in shape, but have amoeboid movements, they are able to penetrate the walls of blood vessels and leave the bloodstream. The normal content of leukocytes in the blood ranges from 4000-5000 to 8000-9000 per 1 mm 3.
Distinguish between granular leukocytes, or granulocytes (contain specific granularity in the cytoplasm), and non-granular, or agranulocytes (Fig. 2). Depending on the nature of granularity when stained according to Romanovsky - Giemsa, granulocytes are divided into neutrophilic, eosinophilic and basophilic. Neutrophilic leukocytes have fine granularity of brownish-violet color. Eosinophilic leukocytes with abundant large orange-red granularity and basophilic with large dark purple granules of various sizes. granulocytes are pink in color, their nuclei are irregular in shape, sometimes in the form of a curved cord (stab), often divided into lobules connected by thin bridges (segmented).
Agranulocytes (lymphocytes and monocytes) are distinguished by a basophilic (blue) cytoplasm and an unsegmented nucleus. Compared to the lymphocyte (see), the monocyte has a larger size (12-20 microns), a light-colored nucleus of an irregular (more often horseshoe-shaped) shape, a smoky-blue cytoplasm, sometimes with a dusty red granularity. In diseases of the blood, in addition to the listed mature forms of leukocytes, 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 towards the nucleus. Leukocytes have a number of important functions, in particular in protecting the body (see Antibodies,), in wound healing, interstitial metabolism, etc.
Rice. 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.
Leukocytes (from the Greek. Leukos - white and kytos - cell) - white blood cells, one of the types of blood cells. Leukocytes are round-shaped cells with a nucleus and a homogeneous or granular protoplasm. In human blood, granular leukocytes are distinguished - granulocytes and non-granular leukocytes - agranulocytes. Granulocytes include leukocytes with neutrophilic, eosinophilic and basophilic granularity, to agranulocytes - lymphocytes (see) and monocytes. Neutrophilic leukocytes - neutrophils - cells with a diameter of about 12 microns. Their protoplasm is stained by the Romanovsky-Giemsa method in pink, that is, it is oxyphilic, and the grains are purple (neutrophilic granularity). The nucleus is rich in chromatin, polymorphic; in young cells bean-shaped or sausage-shaped (young), in others it is elongated in the form of sticks, horseshoe (stab) and in the most mature it is divided by constrictions into separate segments (segmented). The constrictions can sometimes be invisible, which led some authors to take the segments for separate nuclei and call such cells polynuclear cells, in contrast to mononuclear cells - large mononuclear cells of a lymphoid nature with azurophilic granularity. This opposition should be considered incorrect, since all leukocytes are essentially mononuclear cells. Currently, instead of "polynuclear", the commonly accepted name is "segmented" leukocyte. "Young" neutrophils are usually not found in normal blood. Their appearance speaks of a regenerative shift - a nuclear shift "to the left" (see Leukocyte formula).
An increase in the number of cells with a segmented nucleus is a shift "to the right". In some inflammatory and infectious diseases (pneumonia, sepsis, purulent processes), the grains in the protoplasm of neutrophils are coarser, uneven in size, unevenly colored, which is commonly called toxic (toxigenic) granularity of neutrophils. At the same time, a nuclear shift is usually observed. Often, simultaneously with toxic granularity in the protoplasm of neutrophils, there are so-called Dele little bodies (more precisely, Knyazkova - Dele) - pale blue lumps of various shapes.
Eosinophilic leukocytes - eosinophils - with a diameter of about 12 microns. Their protoplasm is weakly basophilic, stained bluish, and the granularity in it is well stained with eosin in a bright pink color. The nucleus is less lobular than that of a neutrophil, usually consisting of two segments. Basophilic leukocytes - basophils - about 8-10 microns in diameter with oxyphilic protoplasm, staining pink. The grains are large, of various sizes, they are dyed metachromatically with basic paints in a dark purple color. The core consists of 3-4 segments and resembles a maple leaf.
Monocyte is the largest cell of normal blood - with a diameter of 12-20 microns. The nucleus is often located eccentrically, oval or horseshoe-shaped, has a wide-lobed chromatin network, and is colored red-violet. Protoplasm turns dark gray with a bluish tint. Sometimes it is possible to notice fine azurophilic granularity in the protoplasm.
Physiology of leukocytes. One of the main functions of leukocytes is to protect the body from microbes and foreign substances that penetrate the blood or tissues (function of purification, detoxification). An important property of leukocytes is their ability for amoeboid movement, which is 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 the glands into the digestive tract, with the products of inflammation, rapidly breaking down. The life span of leukocytes is short - 2-4-10 days. Leukocytes have a significant secretory capacity (release of alexins, bactericidal substances such as lysozyme), seroimmunological activity (the formation of antibodies - leukocytolysins, leukoagglutinins), are involved in the processes of interstitial metabolism. Leukocytes have a pronounced enzymatic activity, various enzymes are found in them: oxidase, amylase, catalase, lipase, phosphatase. Eosinophils are mainly attributed to the detoxification function, their number increases in allergic conditions, helminthiasis, skin diseases and decreases at the height of infectious diseases, in case of poisoning. The function of basophils has been little studied; they indicate their participation in the formation of heparin and histamine. Monocytes have phagocytic ability. The sedimentation of leukocytes is a phenomenon similar to the sedimentation of erythrocytes (see).
Due to the complexity of the determination and the inconsistency of the results obtained, the determination of the leukocyte sedimentation rate has not entered clinical practice.
Leukocytes with erythrocytes and platelets are formed by the hematopoietic immune system, which contains:
- tonsils;
- Bone marrow;
- thymus gland (thymus);
- lymphoid formations in the intestine (Peyer's patches);
- spleen;
- The lymph nodes.
Bone marrow is the main site for the formation of leukocytes. These cells are produced in the body in large numbers, because after the destruction of the harmful body, they die along with it.
Bodies are distributed in the following fluids of biological origin: in blood plasma, in urine (in a small amount in a healthy person), in a woman's vaginal lubrication, etc.
The structure and how they look
The shape of the leukocytes is round or oval. Their color is considered to be white, since there is no independent color. In order to see leukocytes under a microscope, the biomaterial is pre-stained, each type of body reacts to the color in its own way.
Cell morphology:
- granulocytes are granular;
- agranulocytes are not granular.
The simplified structure of leukocytes is characterized by the presence of a nucleus and cytoplasm, but each type has its own structural features:
- Neutrophilic. The cytoplasm is fine-grained with a homogeneous narrow border, which contains thin filaments. The cytoplasm also contains mitochondria, organelles, the Golgi complex, inclusions of glycogen, lipids, and the granular endoplasmic reticulum. The nucleus contains dense chromantin.
- Eosinophilic. The nucleus includes heterochromatin. The cytoplasm contains granules of two types:
- oval, 0.5-1.5 microns in size, containing amino acid - arginine, hydrolytic enzymes;
- round, 0.1-0.5 microns in size, containing arylsulfatase and acid phosphatase.
- Basophilic. The cytoplasm includes rounded large basophilic granules with a diameter of 0.5-1.2 microns. They contain acidic glycosaminoglycan heparin and histamine. The nucleus is weakly lobed, sometimes spherical.
Lymphocytes are characterized by a rounded nucleus with an intense color and a small rim of the cytoplasm, in which there is an insignificant content of ribosomes and polysome. The nucleus is round with chromatin condensed along the periphery.
Depending on the structural features and functions of cells, the life span of leukocytes in human blood has the following range: from 2 to 15 days. The exception is lymphocytes, which live from a couple of days to several years, some of them accompany a person throughout his life.
What are
In the medical society, a classification of leukocytes has been formed according to morphological and functional characteristics.
Varieties of leukocytes according to the structure of the cytoplasm:
- Granulocytes are granular leukocytes or polymorphonuclear leukocytes.
- Agranulocytes are non-granular.
Leukocytes include types of bodies such as neutrophils, eosinophils, basophils, lymphocytes and monocytes, which differ in their functions:
- Neutrophilic leukocytes. They make up 50-70% of the total number of leukocytes, they are mainly involved in the destruction of harmful particles. They produce keylones - substances for suppressing DNA synthesis in cells. Neutrophils, in turn, are of 2 types: segmented (mature cells) and stab (young cells with an elongated nucleus).
- Eosinophils - provide movement to the site of the attack, absorb harmful agents, eliminate unnecessary allergic manifestations by blocking histamine with the help of the histaminase enzyme.
- Basophils - "ambulance" when exposed to human tissue poisons, toxic substances, vapors. They take part in the processes of blood clotting.
- Lymphocytes. It is the main building block of the immune system. It activates a retaliatory strike against aggressive bacteria and viruses, stores information about it and, when attacked again, reacts even faster, transforming into lymphoblasts, which differ in the rate of reproduction. Then the lymphoblasts turn into killer cells and completely eliminate the intruder. This is how immunity is formed and works.
- Monocytes absorb elements of especially large sizes. With their help, inflamed tissues, dead cells and bodies of dead leukocytes are removed from the body through urine and purulent discharge. Monocytes are characterized by phagocytic activity - the ability to bind, absorb and digest microbes and bacteria.
What do leukocytes do
The value of leukocytes and their function:
- Informational. Fluctuations in the values of cell concentration mean that some changes are taking place in the human body, which may be associated with a harmless change in physical condition (fatigue, depression) or with the development of pathologies (increased indicators indicate cancer).
- Protection of the body from the harmful effects of foreign cells. When a small pathogen enters the bloodstream, they absorb and destroy it. If the danger is large, then the number of leukocytes increases, their group captures the enemy and also destroys. This process is called phagocytosis.
- Hemostatic functionality - ensuring blood clotting by synthesizing histamine and heprin - direct anticoagulants.
- The production of antibodies means that active protein compounds of the blood plasma are produced to fight the causative agent of the disease, prevent the multiplication of microorganisms and neutralize the toxic substances that they release.
- Transport - the bodies are involved in the transfer of adsorbed amino acids, enzyme substances and active components to the tissues of the organs, moving through the blood vessels.
- Synthetic - the formation of histamine and heparin, which regulate physiological processes in the body (production of pancreatic juice, muscle spasm, lowering blood pressure).
- With the development of a disease in the body, such a process occurs as the emigration of leukocytes, in which protective cells leave the blood vessels, passing through their walls, and go to the diseased tissues, eliminating the lesion. At the same time, the capacity of the vessels increases and chemotaxis is activated - the process of chemical attraction of cells to inflamed tissues. All this contributes to the correct migration of leukocytes and the speedy destruction of enemy cells.
In the form with the results of blood tests, the general designation of leukocytes is as follows: WBC - white blood cells (white blood cells), the unit of measurement of bodies is 10 to the 9th degree of cells / l. For a detailed study of the leukocyte formula, differentiation of indicators by cell types is used, which is expressed as a percentage. Often it is considered in conjunction with the indicators of the average volumes of erythrocytes (referred to as MCV - mean corpuscular volume).
Blood norm and deviations
In adults and children, the indicators of leukocytes in the blood constantly change depending on the physical condition of the person. But there are permissible limits for their concentration - from 4 to 9x10 to the 9th power of cells / l, any fluctuations in values show that some changes are taking place in the body.
A reduced number of cells in the blood indicates a decline in the body's defenses, a malfunction in the immune or hematopoietic system. A low white body count is called leukopenia, which is functional and organic.
Functional occurs with the following factors:
- exhaustion, lack of nutrition, the transition to a strict diet;
- defeat by a viral disease;
- weakening of the body, being in an anaphylactic state;
- taking analgesics and antiviral drugs;
- ionizing effects of medical devices (x-rays).
Organic signals the development of the following life-threatening conditions:
- acute leukemia - a cancer of the blood;
- aplastic anemia is a violation of the process of hematopoiesis.
A case of an elevated white blood cell count is called leukocytosis. There are 3 types of it:
- Redistributive - has no connection with pathology, arises from external influences on the body, which include:
- the effect of alcoholic or narcotic drugs;
- consuming energy drinks;
- as a result of a surgical operation;
- Reactive - appears as a result of pathological processes in the body, including:
- poisoning, intoxication;
- inflammation;
- exposure to infections or bacteria.
- Persistent - characterized by high rates (about 80x10 9 cells / l) and indicates the presence of an oncological disease.
Jumps in indicators can be observed in the absence of diseases. The changes are caused by the following reasons:
- pregnancy;
- puberty;
- taking hormonal drugs;
- stress, depression;
- bright positive emotions;
- climate change;
- a change in the nature of food.
In order for the analysis result to be correct, the following rules must be observed:
- Do not consume alcoholic beverages or medications 72 hours before going to the hospital.
- Do not eat sweet, fatty, smoked food before donating blood for 12 hours.
- Do not smoke during the day.
- Do not donate blood if you feel unwell and weak.
In order to make a correct diagnosis, the doctor must prescribe a detailed blood test, in which the concentration of white blood cells will be described for each type. The characteristic of leukocytes by their number and ratio is indicated in the leukocyte form or formula. In its study, a specialist pays attention to the shift index - an analysis of the ratio of mature and immature nuclei to determine the severity of the disease:
- heavy - 1.0 and higher;
- average - 0.3-1.0;
- light - no more than 0.3.
An increased leukocyte concentration is a contraindication for a number of procedures: surgery, hysteroscopy, laparoscopy, etc.
Problems in the hematopoietic system are indicated by the state of lymphocytosis - an increased level of lymphocytes, which normally should be 19-37% of the total number of leukocytes. It is of 2 types:
- Relative. The total number of leukocytes remains normal.
- Absolute. Leukocytes and lymphocytes increase.
The development of lymphocytosis indicates the presence of a virus in the body (flu, AIDS, herpes, rubella, chickenpox) or cancer.
How to treat
Deviations from the norm of the concentration of leukocytes in the blood to the higher and lower side indicate the course of the pathological process in the human body. The most dangerous diseases causing these abnormalities are leukemia and aplastic anemia.
Principles of leukemia treatment:
- Chemotherapy is the introduction of drugs intravenously, orally, or into the cerebrospinal fluid (there are cases of using all 3 methods at the same time).
- Radiation therapy is a treatment with ionizing radiation.
- Targeted therapy - identifying cancer cells and killing them without harming healthy cells.
Treatment principles for aplastic anemia:
- Immunosuppressive therapy - includes the introduction of immunoglobulin and cyclosporin A. As an additional aid, transfusion of platelets and red blood cells is used.
- Allogeneic bone marrow transplantation gives the most favorable prognosis, but the possibility of carrying out the procedure is reduced due to the difficulty of selecting a donor that will be immunologically compatible with the patient.
In contact with
The number of leukocytes is an important indicator for the diagnosis of pathological conditions. In the body, leukocytes are constantly produced, and their content in the blood can change during the day. How are these cells produced and what role do they play in the human body?
Several types of shaped elements float in the blood, which support the health of the whole organism. White cells that have a nucleus inside are called leukocytes. Their feature is the ability to penetrate the capillary wall 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 characteristics.
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 protection of the body from the ingress of any foreign agents. The main functions of white cells are as follows:
- Antibody production.
- Absorption of foreign particles - phagocytosis.
- Destruction and removal of toxins.
Each type of white blood cell is responsible for certain processes that help in the implementation of the main functions:
- Eosinophils. They are considered the main agents for the destruction of allergens. Participate in the neutralization of many foreign components with a protein structure.
- Basophils. Accelerate healing processes in the focus of inflammation, due to the presence of heparin in its structure. Updated every 12 hours.
- 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 inflammations provoke a sharp production of such cells by the body, which is immediately reflected in the leukocyte formula as an increased amount.
- Monocytes. Helps neutrophils. They are more active if an acidic environment develops in the focus of inflammation.
- Lymphocytes. They distinguish their own cells from foreign ones in structure, participate in the production of antibodies. They live for several years. They are the most important component of immune defense.
Important: Many doctors are forced to do a clinical blood test before prescribing treatment. Viral and bacterial diseases cause different changes in the analysis, which makes it possible to make the correct diagnosis and prescribe the necessary drugs.
All types of white blood cells are produced in the bone marrow, which is located inside the bones. It contains a huge number of immature cells, similar to those found in the embryo. From them, as a result of a complex multistage 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-fledged "maturation" they will need to mature in the lymphoid organs.
In the bone marrow, leukocytes accumulate, 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 an insignificant part of all the body's leukocyte reserves (up to 2%) floats in the bloodstream.
In the inflammatory process, all cells rush to the place of its localization. The reserves of neutrophils for such emergency surges are located on the walls of the vessels. It is this depot that enables 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 divide 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 leukocytes
Leukopenia in an adult is a condition when the number of leukocytes is below 4 * 10 9 / l. It can be caused by malignant diseases, exposure to radiation, vitamin deficiencies or problems with the function of hematopoiesis.
Leukopenia leads to the rapid development of various infections, a decrease in the body's resistance. The person feels chills, the body temperature rises, there is a breakdown and exhaustion. The body tries to compensate for the lack of defense cells, as a result of which an enlargement of the spleen is noted. 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. They often arise due to a decrease in the body's defenses.
Excess white blood cells
The number of leukocytes above 9 * 10 9 / l is considered an excess of the norm and is called leukocytosis. Physiological increase, which does not require treatment, can be caused by food intake, physical activity, some hormonal surges (pregnancy, premenstrual period).
The following causes of leukocytosis lead to pathological conditions:
- Infectious diseases.
- Inflammatory processes of microbial and non-microbial etiology.
- Blood loss.
- Burns.
Treatment for this condition may include the following groups of drugs:
- Antibiotics Helps eliminate the infection that caused leukocytosis and prevent complications.
- Steroid hormones. Quickly and effectively relieve inflammation, which leads to a decrease in the production of white blood cells.
- Antihistamines. They also help reduce inflammation.
The tactics of treating any changes in the leukocyte count depends on the cause that caused them.
Important: minor changes in the leukocyte formula can be temporary and even considered normal. Strong discrepancies with acceptable values or the absence of changes during repeated analyzes should alert you.
Children are taught about the importance of leukocytes at school. This topic is not an exaggeration. Good immunity ensures health and a good quality of life for 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 correctly interpret the results.
Video - What does an increase in leukocytes in a blood test mean?
Human blood consists of a liquid substance (plasma) only 55-60%, and the rest of its volume is accounted for by the formed elements. Leukocytes are perhaps the most surprising of them.
They are distinguished not only by the presence of a nucleus, especially large size and unusual structure - a unique function assigned to this shaped element. About her, as well as other features of leukocytes, will be discussed in this article.
What does a leukocyte look like and what shape does it have?
Leukocytes are spherical cells up to 20 microns in diameter. Their number in humans ranges from 4 to 8 thousand per 1 mm3 of blood.
It will not be possible to answer the question of what color the cell is - leukocytes are transparent and are defined by most sources as colorless, although the granules of some nuclei can have a rather wide color palette.
The variety of types of leukocytes made it impossible to unify their structure.
- Segmented.
- Unsegmented.
Cytoplasm:
- Grainy;
- Homogeneous.
In addition, the organelles that make up the cells differ.
The structural feature that unites these seemingly dissimilar elements is the ability to move actively.
Young cells are producedfrom multipotent stem cells in the bone marrow. Moreover, to generate a workable leukocyte 7-9 divisions can be involved, and the place of the divided stem cell is taken by the cell-clone of the neighboring one. This is how the constancy of the population is maintained.
Inception
The process of formation of leukocytes can be completed:
Life span
Each type of white blood cell has its own life expectancy.
Here's how long a healthy person's cells live:
- from 2 hours to 4 days -
- from 8 days to 2 weeks - granulocytes;
- from 3 days to 6 months (sometimes up to several years) - lymphocytes.
The shortest lifespan characteristic of monocytes is due not only to their active phagocytosis, but also to the ability to give rise to other cells.
Monocytes can develop:
The death of leukocytes can occur for two reasons:
- Natural aging of cells, that is, the completion of their life cycle.
- Cell activity associated with phagocytic processes- the fight against foreign bodies.
The fight of leukocytes with a foreign body In the first case, the function of destroying leukocytes is assigned to the liver and spleen, and sometimes to the lungs. Cell decay products are excreted naturally.
The second reason is associated with the course of inflammatory processes.
Leukocytes die directly "On duty", and if their removal from there is impossible or difficult, the decay products of cells form pus.
Video - Classification and significance of human leukocytes
The general function, in the implementation of which all types of leukocytes are involved - protection of the body from foreign bodies.
The task of cells is reduced to their detection and destruction in accordance with the principle "Antibody-antigen".
The destruction of unwanted organisms occurs by their absorption, while the receiving phagocyte cell significantly increases in size, perceives significant destructive loads and often dies.
The place of death of a large number of leukocytes is characterized by edema and redness, sometimes by suppuration, and an increase in temperature.
An analysis of its variety will help to more accurately indicate the role of a particular cell in the process of fighting for the health of the organism.
So, granulocytes perform the following actions:
- Neutrophils- capture and digest microorganisms, stimulate the development and division of cells.
- Eosinophils- neutralize foreign proteins in the body and its own dying tissues.
- Basophils- promote blood coagulation, regulate the permeability of blood vessels.
The list of functions assigned to agranulocytes is more extensive:
- T-lymphocytes- provide cellular immunity, destroy foreign cells and abnormal cells of body tissues, resist viruses and fungi, affect the process of blood formation and control the activity of B-lymphocytes.
- B-lymphocytes- support humoral immunity, fight bacterial and viral infections by generating antibody proteins.
- Monocytes- perform the function of the most active phagocytes, which became possible due to the large amount of cytoplasm and lysosomes (organelles responsible for intracellular digestion).
Only in the case of coordinated and well-coordinated work of all types of leukocytes is it possible to maintain the health of the body.
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