Chemical and cellular composition of blood. Department of Biochemistry. Concentration of hydrogen ions and regulation of blood pH

Blood is a biological fluid that provides organs and tissues with nutrients and oxygen. Together with lymph, it forms a system of fluids circulating in the body. Performs a number of vital functions: nutritional, excretory, protective, respiratory, mechanical, regulatory, thermoregulatory.

The composition of human blood changes significantly with age. It should be said that children have a very intensive metabolism, therefore in their body it is much more per 1 kg of body weight compared to adults. On average, an adult has about five to six liters of this biological fluid.

The blood contains plasma (liquid part) and leukocytes, platelets). Its color depends on the concentration of red blood cells. Plasma that is devoid of protein (fibrinogen) is called serum. This biological fluid has a slightly alkaline reaction.

Biochemical composition of blood - buffer systems. The main blood buffers are hydrocarbonate (7% of the total mass), phosphate (1%), protein (10%), hemoglobin and oxyhemoglobin (up to 81%), as well as acidic (about 1%) systems. Plasma is dominated by bicarbonate, phosphate, protein and acidic, in erythrocytes - bicarbonate, phosphate, in hemoglobin - oxyhemoglobin and acidic. The composition of the acidic buffer system is represented by organic acids (acetate, lactic, pyruvic, etc.) and their salts with strong bases. The hydrocarbonate and hemoglobin buffer systems are of the greatest importance.

The chemical composition is characterized by the constancy of the chemical composition. Plasma makes up 55-60% of the total blood volume and is 90% water. are organic (9%) and mineral (1%) substances. The main organic substances are proteins, most of which are synthesized in the liver.

Protein composition of blood. The total protein content in the blood of mammals ranges from 6 to 8%. About a hundred protein components of plasma are known. They can be conditionally divided into three fractions: albumins, globulins and fibrinogen. Plasma proteins that remain after removal of fibrinagen are called serum proteins.

Albumin is involved in the transport of many nutrients and (carbohydrates, fatty acids, vitamins, inorganic ions, bilirubin). Participate in regulation Serum globulins are divided into three fractions - alpha, beta and gamma globulins. Globulins transport fatty acids, steroid hormones, and are immune bodies.

Carbohydrate composition of blood. Plasma contains monoses (glucose, fructose), glycogen, glucosamine, monoses phosphates and other products of intermediate carbohydrate metabolism. The bulk of carbohydrates are glucose. Glucose and other monoses in blood plasma are in a free and protein-bound state. The content of bound glucose reaches 40-50% of the total carbohydrate content. Among the products of intermediate metabolism of carbohydrates, lactic acid is distinguished, the content of which increases sharply after heavy physical exertion.

The concentration of glucose can change in many pathological conditions. The phenomenon of hyperglycemia is typical for diabetes mellitus, hyperthyroidism, shock, anesthesia, and fever.

Lipid composition of blood. Plasma contains up to 0.7% and more lipids. Lipids are in a free and protein-bound state. Plasma lipid concentration changes in pathology. So, with tuberculosis, it can reach 3-10%.

Blood gas composition. This biofluid contains oxygen (oxygen), carbon dioxide and nitrogen in free and bound states. So, for example, about 99.5-99.7% of oxygen is associated with hemoglobin, and 03-0.5% is in a free state.

The tissue of the body, consisting of plasma and corpuscular elements suspended in it - erythrocytes, leukocytes and platelets. Carries out the transport of gases and substances in the body, and also performs protective, regulatory and some other functions.

Human blood makes up approximately 8% of the total body weight. This is a special connective tissue, a vital biological fluid.

Blood constantly circulates through our body and without this movement life is simply impossible. It penetrates into all organs and tissues and can change its composition depending on the state of the body. That is why, based on one blood test, it is often possible to obtain information about past and existing diseases, the general condition of the body and disorders in various organs.

What is the correct way to understand the results obtained? What is blood made of and what are its components important? What are blood groups, what is their difference and why is it so important to know them during transfusion? You will find answers to these and many other questions in this article.

Blood in adults

The volume of blood in the human body is 4 to 6 liters. It is a multicomponent connective tissue, consisting mainly of specific cells and liquid plasma. The ratio of elements is conditionally stable and may vary depending on age, health status, previous infections and other factors.

In the body, blood has several important functions:

• Transport of substances.

Thanks to the movement of blood, the organs receive the necessary nutrients and get rid of metabolic products. In particular, it is the blood that supplies all parts of the body with oxygen. The supply and cleaning take place continuously, and the suspension of this process, for example, when a vessel is blocked for only 10-15 minutes, can lead to irreversible consequences for the starving tissue - the development of necrosis.

• Homeostasis (providing a constant internal environment in the body).

Human blood is responsible for life support and tissue regeneration, water and electrolyte balance. She also controls body temperature.

• Immunity.

It is in the blood that there are protective cells (leukocytes) and antibodies to various antigens. Without this tissue, we would not be able to fight various types of pathogens.

• Turgor.

Due to the constant flow of blood, the organs retain their shape and tissue tension.

Blood in men

Men have more blood volume than women - up to 6 liters. At the same time, the concentration of erythrocytes in it is higher, and therefore, of hemoglobin (135-160 g / l), which is responsible for the transport of oxygen. This is extremely important for the body's endurance, because during physical exertion, the need for this gas in organs and tissues increases. The peculiarity of male blood allows it to be delivered faster, which means that it is possible to withstand the load longer.

The erythrocyte sedimentation rate in male blood is lower - up to 10 mm / h. In women, this indicator can go up to 15 mm / h, which in the male analysis will indicate the development of the inflammatory process. Also, unlike the blood of women, the male is relatively constant in composition throughout life.

Blood in women

The total blood volume in the female body is less - 4-5 liters, and it can vary in composition. This is most clearly reflected in the norm of hemoglobin, which can significantly decrease during menstruation or pregnancy. On average, the blood of women contains 120-140 g / l, however, the fairer sex can tolerate lower levels. For example, anemia up to 90 g / l may manifest itself with only slight fatigue.

Pregnancy significantly affects a woman's blood counts. First of all, the level of hormones rises - estrogen, progesterone, prolactin. The volume of circulating blood also changes, because the circulatory system of the growing fetus is connected to the mother's body. An increase in volume affects blood saturation: for example, the amount of protein in the plasma decreases, the level of hemoglobin and creatinine decreases.

But other indicators in the general blood test may increase:

• Insulin levels often exceed the norm, doctors have even singled out a separate diagnosis - pregnancy diabetes. This condition is temporary and goes away after childbirth.
• Since metabolic processes are noticeably accelerated in the body of a pregnant woman, the blood of women is saturated with cholesterol. Its level during this period, as a rule, is higher than the norm.
• An increased concentration of uric acid can be an indicator of malfunctioning of the kidneys, even intoxication.
• A slight excess of the norm of potassium, chlorine, phosphorus and sodium is observed in healthy pregnant women and is not a dangerous symptom.

Another feature of the blood of women during pregnancy is a significant increase in clotting rates. This is a natural process of preparing the body for an increase in blood levels and a certain defense against possible blood loss during childbirth.

Anemia of pregnancy

The body of a pregnant woman needs an increased intake of iron, so one of the most common diagnoses during this period is iron deficiency anemia. Most often it manifests itself in the second half of pregnancy, but with a weakened body or low weight, anemia can be observed already from the first weeks.

Anemia is diagnosed if the hemoglobin level in the blood falls below 110 g / l. Tissues and organs receive less oxygen, which is transported by hemoglobin, and the woman feels general weakness, fatigue, dizziness and headaches, shortness of breath appears. But the most dangerous thing with anemia of pregnant women is oxygen starvation of the fetus, which affects the growth and development, in severe cases it can provoke a miscarriage or placental abruption.

Blood in lactating women

The milk of a breastfeeding woman is produced from the blood plasma. Therefore, its composition can affect milk. So, in particular, certain types of drugs can be passed on to the baby. Moreover, breastfeeding is safe for diseases that are transmitted through the blood: B and C, HIV. Therefore, if blood tests are positive for these infections, breastfeeding can usually be continued.

The composition of blood in children is notable for its instability - in the process of growth, the ratio of the main components is constantly changing. In addition, the indicators are highly dependent on external factors: diet, daily regimen, physical activity. The level of leukocytes in children's blood is increased, since it is during this period that the active formation of immunity takes place - blood cells constantly encounter new antigens, antibodies are produced. After birth and until adolescence, the blood in children gradually comes to the indicators of an adult: coagulability improves, the erythrocyte sedimentation rate increases, and the total number of formed elements returns to normal.

Blood in newborns

As a percentage, the amount of blood in a newborn is much higher than that of an adult - it is about 14% of the body weight, it turns out that about 150 ml per 1 kg of weight. In the first 12 hours, the blood in children is characterized by an increased level of immature erythrocytes and hemoglobin. However, already in the first day, these indicators fall significantly. The fact is that erythrocytes in the blood of newborns live much less than in an adult organism - they are destroyed on average in 12 days.

Premature babies often have anemia in the first months of life. If, with such a decrease in hemoglobin, the general state of health does not cause concern, no additional symptoms appear, then early anemia of prematurity is not considered dangerous and is a common reaction to adaptation to new conditions.

After the baby is born, up to 150 ml of blood with specific characteristics is stored in the placenta and umbilical vein. Previously, they did not attach much importance to it, but today more and more umbilical cord blood is saved. It contains a large number of stem cells that can be used in the treatment of various diseases. They are unique in their characteristics, since they are not differentiated, they can produce offspring of any specialized cell types.

The circulatory system consists of the heart, which pumps blood, and the hollow vessels through which it flows. In the human body, blood moves in two circles:

• Small passes only through the heart and lungs. Here the blood is enriched with oxygen and gives off carbon dioxide - which is why we breathe it out.
• The great circle begins in the heart and runs through all other tissues and organs. Through this circle, the blood provides the transport of nutrients to all parts of the body.

Vessels are hollow tubes of different diameters through which blood flows continuously and under pressure.

Artery blood

Arteries are the vessels through which blood flows from the heart muscle to various organs. It is oxygen-rich blood, purified from metabolic products, which delivers the necessary substances. In a small circle, arterial blood, on the contrary, flows through the veins to the heart.

The arteries pulsate in the rhythm of heart contractions - these shocks are well felt if you press the vessel slightly with your fingers. Therefore, it is through the arteries that the pulse is measured. Also, according to the strength of the blood flow in them, blood pressure is determined - one of the key indicators of the work of the cardiovascular system.

The vessels differ in diameter; the aorta is the largest in the human body. The walls of the arteries are quite dense and elastic, capable of withstanding great pressure. At the same time, it is damage to arteries, especially large ones, that cause rapid blood loss of a large volume, since blood is poured out of the vascular bed under pressure. Arterial blood is bright scarlet in color.

Veins are vessels that carry blood from organs to the heart. It is deprived of oxygen, enriched with carbon dioxide and other metabolic products. The main function of blood from a vein is to transport waste produced by organs.

The movement of blood through the arteries is provided by the impulses of the heart. But it passes through the veins due to venous impulses and moves with the help of special venous valves. The pressure here is less than in the arteries, moreover, they need to raise blood from the lower extremities, therefore these are vessels with developed musculature of the walls. If, for some reason, the vessels are weak, and the valves do not work effectively enough, varicose veins develop.

Among the largest veins in diameter are the jugular, superior and inferior vena cava. Damage to them also leads to serious blood loss.

Blood from a vein is dark, thick, normally warmer than arterial blood. All veins and arteries are connected by capillaries located in organs - it is passing through them that the blood gives off oxygen and other nutrients, and also takes carbon dioxide.

Blood: general characteristics of the constituents

Human blood is a multicomponent liquid. 40-45% are formed elements: erythrocytes, leukocytes, platelets. The remaining 55-60% is occupied by plasma - the liquid part, consisting mainly of water, through which cells move. The ratio of elements to plasma is called hematocrit. Normally, in men, it ranges from 0.40-0.48, and in women it is lower - 0.36-0.46.

Each component of the blood performs its functions, its increased or decreased level in the analysis indicates the presence of diseases, can threaten life. Form elements are produced by the bone marrow, therefore, their lack or defective form may indicate disruptions in its work.

Erythrocytes

Red blood cells are red blood cells that are responsible for transporting oxygen and carbon dioxide. They perform this function due to hemoglobin - an iron-containing protein that can attach oxygen to itself when the blood passes through the pulmonary circulation. The cytoplasm of a healthy blood cell is 98% composed of this protein. It is he who gives it its characteristic red color.

Lack of red blood cells is the main cause of anemia. However, in some cases, a marriage is also found in the cells themselves - with a sufficient number of red blood cells, the hemoglobin content in them is lowered. Such deviations from the norm cause oxygen starvation of organs and tissues, and can lead to other diseases.

Erythrocytes are the most numerous formed elements, they make up about 99% of their total volume, as well as ¼ of all cells in the human body.

In shape, erythrocytes resemble a disc concave in the center. If, for some reason, their shape changes, this also becomes the cause of blood diseases.

• Function: transport of gases.
• The amount in a liter of blood: for men - 3.9-5.5 x 1012, for women - 3.9-4.7 x 1012, for newborns - up to 6.0 x 1012.
• Size: diameter - 6.2-8.2 microns, thickness - 2 microns.
• Life time: 100-120 days.

Leukocytes

Leukocytes are white blood cells that vary in size and appearance. Moreover, they all have no color and are nuclear cells. The following types of leukocytes are distinguished: lymphocytes, basophils, neutrophils, eosinophils and monocytes. Despite the difference in size and type, they all perform the same function - to protect the body from various antigens. These cells are able to penetrate through the capillaries into the tissues of organs, where they are attacked by foreign microorganisms.

Different types of leukocytes are highly specialized blood cells that appear in specific diseases. Therefore, their presence, type, quantity in a general blood test can tell the doctor what kind of infection is present in the body and at what stage it is. The onset of the course of the disease and the acute period are characterized by an increased level of young leukocytes, with recovery, on the contrary, eosinophil cells predominate in the blood. With viral infections, the number of lymphocytes increases, with bacterial - different types of neutrophils, and with sluggish infections in the blood, the content of monocytes is increased. Deciphering blood by leukocytes also helps to understand how effective the prescribed treatment is.

Leukocytes are able to capture foreign bodies and absorb them, but in the process of fighting, most of the white blood cells die. In these places, decay products accumulate - pus is formed.

• Function: phagocytosis is a protective reaction of the body.
• Quantity in a liter of blood: adults - 4-9x109, children under one year old - 6.5-12.5x109.
• Size: depends on the type of leukocyte.
• Lifetime: 2-4 days, some forms 10-12 days, lymphocytes can remain throughout life.

Platelets

Platelets are colorless and non-nuclear cells that are responsible for stopping bleeding in the first stage. One of the main features of these shaped elements is activation from the slightest stimulus. In a normal state, platelets travel through the bloodstream, however, as soon as an impulse arrives, they change and acquire the ability to stick together and stick to the vessel wall. Due to this, they clog even the smallest damage to the walls of blood vessels, prevent bleeding.

Similar processes occur in the body all the time, but in some diseases, the formation of blood clots is dangerous. For example, with atherosclerosis - a decrease in the diameter of the arteries due to cholesterol deposits on their walls. In this case, a detached thrombus can be carried by the blood flow to another part of the cardiovascular system, and block the diseased artery. This is most often the main cause of myocardial infarction.

• Function: blood clotting.
• Quantity in a liter of blood: a blood test can normally show from 180 to 400 thousand cells.
• Size: 2-4 microns, can change the size depending on the need.
• Life time: 5-7 days.

Blood plasma

Blood plasma is a liquid medium in which shaped elements move. It consists of 90-92% water and 10% of organic and inorganic substances. Such a ratio of components ensures normal blood flow, but if the amount of water decreases, rheology also decreases significantly. And this can lead to stagnant processes, an increase in the load on the heart.

10% of blood plasma is accounted for by:

• Proteins - albumin, globulins and fibrinogen.
• Inorganic salts that are responsible for maintaining the pH level and regulating the amount of water - calcium, chlorine, sodium, potassium, magnesium, and others.
• Other substances - glucose, urea, amino acids, uric acid, vitamins, etc.

Plasma is often used as a separate component for blood transfusions.

Since the condition of the blood can determine the presence of infections, as well as the course of various diseases, there are many specialized tests. For example, blood can be tested for viruses and antibodies. A blood test for tumor markers determines specific proteins that are produced by malignant cells. Checking hormone levels can tell about the state of the endocrine system, and for women during pregnancy, about the development of the fetus. Elevated blood sugar is a confirmation of diabetes.

Almost any health diagnosis begins with basic research, among which one of the key is a complete blood count. It is according to his indicators that the doctor judges which diagnostics to prescribe next.

General blood analysis

A general blood test is a study of all formed elements, their quantity and parameters, plasma and hematocrit. Hemoglobin is checked separately, the leukocyte formula and other important indicators are calculated.

Basic research:

• Hemoglobin and erythrocytes are the parameters that are the main parameters for determining anemia.
• The color indicator is how much red blood cells are saturated with hemoglobin. It is necessary to clarify the diagnosis of anemia and the choice of treatment. A normal blood test will be noted in the range of 0.80 to 1.05.
• Leukocytes are an indicator of infection and the presence of immunity to specific types of pathogenic microorganisms. The leukocyte formula (leukogram) is calculated, which shows the percentage of different types of white blood cells.
  • Stab (p / i) neutrophils.
  • Segmented (s / s) neutrophils.
  • Eosinophils - may indicate recovery from an infectious disease, as well as allergies or helminthic invasions.
  • Basophils.
  • Lymphocytes are cells responsible for acquired immunity. Their presence suggests that the person has had an infection in the past.
  • Monocytes.
• ESR (erythrocyte sedimentation rate) may indicate the development of an inflammatory process.
• Platelets - a low level indicates a deterioration in blood clotting. In some cases, this is normal, such as during menstruation and when taking medications that affect blood clots.

For analysis, blood is taken from a vein or from a finger.

This is a more complex study that provides a broader picture of a person's health status. Thanks to the biochemical analysis of blood, the doctor can judge the functional state of organs and tissues, suspect the development of pathological processes (for example, malignant neoplasms). It also checks the effectiveness of therapy, makes adjustments to the prescribed treatment.

The main indicators of biochemistry:

• Glucose ("blood sugar") is the main parameter for the diagnosis of diabetes mellitus.
• Cholesterol is tested in two types: LDL (low density, LDL), HDL (high density, HDL). It is dangerous to increase the first, since it is an indirect confirmation of the presence of atherosclerosis. When decoding blood, attention is paid, first of all, to him.
• The coefficient of atherogenicity (Ka) is a calculated indicator of the degree of risk of developing atherosclerosis in humans.
• Urea and creatinine show kidney function, an increased rate indicates impaired filtration.
• Lipids, in particular triglycerides and phospholipids, which are responsible for the structural and energetic functions of the body.
• Bilirubin and total protein in the blood speak, first of all, of liver diseases.
• Amylase and lipase are important in determining the condition of the pancreas. Elevated amylase indicates inflammation.
• Albumin is the main protein in plasma. Used to clarify other indicators.
• The AST enzyme is needed to assess the work of the heart.
• The ALT enzyme shows how the liver works.
• Rheumatoid factor - certain antibodies, the presence of which indicates various autoimmune diseases.
• Alkaline phosphatase is mainly responsible for bone health. With the help of this indicator of a biochemical blood test, rickets and other diseases can be determined.
• Sodium and chlorine regulate the water and acid-base balance of the blood.
• Calcium and potassium show the state of the cardiovascular system.

This analysis is extremely important for diagnosing general health. Therefore, doctors recommend donating blood for biochemistry at least once a year.

Decoding a blood test

Blood rates are highly dependent on age and gender. In the form, these indicators are most often indicated in a separate column, however, decoding the blood test is solely the task of the doctor. Since deviation from the norm may be caused not by health problems, but by the conditions under which the analysis was submitted. For example, platelet counts may rise after exercise. And blood sugar depends on when and what a person ate the day before, whether he was worried during the test, whether he took alcohol. Nicotine can also change rates.

When to donate blood: preparation for the test

The composition of the blood and the level of some indicators depend on the foods that a person has eaten, therefore the study is carried out on an empty stomach in the morning. Strictly speaking, it should take 8-12 hours from the last meal to the analysis.

In addition, a few days before donating blood, you need to exclude alcohol, fried or too fatty foods, taking medications (for example, aspirin). You should not smoke for at least 1 hour before the examination.

Also, physical activity can affect the results, therefore, before donating blood, you need to sit quietly for 10-15 minutes, restore breathing, and before that, reduce possible loads as much as possible. On the morning of the test, it is better to cancel the morning run and exercise.

Water does not affect blood components, but it can increase the percentage of lymph (?).

For those who donate blood for cholesterol, it is important to cancel drugs that affect this indicator in 2 weeks. They can be taken only if the decoding of the blood test is necessary to check the effectiveness of the treatment.

Blood transfusion (blood transfusion) is a complex tissue transplantation operation, therefore it is carried out in extreme cases and taking into account all possible risks. To date, clear standards have been developed on the feasibility of this procedure. After all, complications from incompatibility can lead to serious consequences, up to and including death.

That said, blood transfusion is a vital treatment for many patients. Some people need blood transfusion on a daily basis.

Donated blood is most often divided into components - erythrocyte mass, plasma, cryoprecipitate and platelet mass. It is their doctors who use them for routine transfusions. This not only reduces the risk of complications, but also makes it possible to use one portion of donated blood for different recipients. Whole blood is also used in blood transfusion, but less frequently.

Reasons for blood transfusion

One of the main indications for blood transfusion is massive blood loss. It can occur as a result of injuries, accidents, vascular diseases, as well as during childbirth. Bleeding is dangerous in that a decrease in the level of blood in the stream affects homeostasis, turgor of organs and the ability of the blood to carry oxygen. Often, blood loss is associated precisely with oxygen starvation, which can be eliminated only by transfusion of whole blood or erythrocyte mass.

Blood transfusion is also prescribed for the following diagnoses:

• Anemia of varying severity and etiology.
• Blood clotting disorders.
• Leukopenia.
• Sepsis.
• Intoxication of the body.
• Chronic and acute purulent processes, for example, in the case of extensive burns.
• Oncological diseases, chemotherapy.

For some infections, liver diseases, and disseminated intravascular coagulation, plasma is used.

Another possible reason for transfusion is elective surgery. If the patient's blood counts and blood levels are normal, it is possible to carry out the so-called self-donation - the collection of his own blood. This completely eliminates the risk of incompatibility.

Blood rate

Normally, the blood in the body is redistributed to circulating and deposited. The first is approximately 60% of the total volume and moves through the cardiovascular system. It is she who pours out with blood loss. The deposited blood is a certain reserve, 40% of the total amount, which is located in the liver, spleen, and connective tissues. In critical situations, it can replace the circulating one.

Thus, blood loss up to 20% does not threaten life - blood is redistributed, blood pressure in the bloodstream does not fall. Of course, this condition leads to anemia, but if the hemoglobin count does not fall below 80-70 g / l, blood transfusion is inappropriate. Saline solutions can be injected into the bloodstream, and only if the condition does not improve, the erythrocyte mass is transfused.

Blood groups I, II, III, IV

In modern medicine, there are several systems for classifying blood types, the most popular of which are 0AB (4 blood groups) and the Rh factor. It is on them that doctors are guided when determining the compatibility of the donor and recipient.

Back in the beginning. In the twentieth century, the Australian immunologist Karl Landsteiner noticed that in some cases, mixing the blood of two patients leads to the adhesion of erythrocytes, the so-called agglutination. This process is irreversible and fatal. In the course of research, the doctor discovered that antigens A and B can be found on the surface of red blood cells, as well as antibodies to them α and β in plasma. The simultaneous presence of antigen and antibodies to it is impossible, therefore 4 blood groups were identified:

• Group 1 (0) - only α and β antibodies.
• Group 2 (A) - A and β.
• Group 3 (B) - α and B.
• 4 Group (AB) - only antigens A and B.

These indicators do not change throughout life - the blood type remains constant from birth to death.

Agglutination is caused by the introduction of an antigen, to which there is an antibody in the blood. For example, for the 2nd blood group (the presence of β), the transfusion of the 3rd group (the presence of B) will lead to complications. Therefore, donors with blood of the 1st group were considered universal, but the owners of AB, on the contrary, were highly specialized. According to modern standards, such compatibility rules do not apply, and blood transfusion is allowed only within one group.

Rhesus factor

Another important indicator for blood compatibility is protein D, which may or may not be present on the surface of the red blood cell. It is his presence that determines the Rh factor - positive RH + and negative RH-.

According to the outdated system, Rh-negative donors were considered universal, since their blood was not perceived as foreign in all patients. That is, blood of group 1 with a negative Rh factor could be transfused to any patient. Now such a combination is unacceptable - only blood with the Rh factor corresponding to the recipient is used. Therefore, today, when carrying out blood transfusion, 8 blood groups are distinguished - 4 positive (0 Rh +, A Rh +, B Rh +, AB Rh +) and 4 negative (0Rh-, A Rh-, B Rh-, AB Rh-).

Since all components, including infections, enter the recipient's body with the donor's blood, the World Health Organization recommends that all donations be checked. First of all, we are talking about diseases that are transmitted through the blood and its components:

• Hepatitis B and C.
• Syphilis.

Until recently, blood transfusion was one of the main routes of transmission of hepatitis, today the percentage of infected has decreased. But the risk still remains. Therefore, if the recipient needs a systematic blood transfusion, it is best to choose permanent donors and get vaccinated against hepatitis B.

If it is necessary to donate blood for a recipient with reduced immunity, it should be additionally checked for a number of other infections. Even if they do not affect the donor, they can lead to serious complications in the patient. For donation, blood is taken from a vein, on average 400 ml.

Diseases of the blood

Under blood diseases, different types of diseases affecting the corpuscles and plasma are combined. Often they become a consequence of pathologies of the bone marrow, because it is in it that leukocytes, erythrocytes and platelets are formed. In some cases, diseases of other organs, which significantly affect the level of blood, its composition, blood flow and the work of the CVS, are also included in the same category. For example, oxygen deprivation can be caused by both red blood cell problems and blockage of blood vessels due to cholesterol plaques.

The symptoms of this group of diseases are directly related to what kind of shape element suffers. So, with a decrease in the level of hemoglobin in the blood, people note the following changes in well-being:

• General weakness.
• Dizziness.
• Fatigue.
• Body aches.

The lack of platelets is expressed in poorly healing wounds, rapid bruising, inability to stop the blood, and internal bleeding.

Often, human blood diseases pass without specific symptoms, are characterized by a general deterioration in well-being and proceed unnoticed for the patient in the first stages. With their development, body temperature may rise, bone pain, fainting, and other severe symptoms may appear.

Laboratory signs of blood diseases

It is impossible to determine the disease by symptoms alone, therefore the final diagnosis is made based on the transcript of a blood test. Moreover, for the initial diagnosis, a standard general study is quite enough.

Erythrocyte level

Red blood cells are responsible for transporting oxygen to cells and removing carbon dioxide in a timely manner. Therefore, if in the general blood test their number is below normal, this is a sign of anemia (anemia).

If the level of red blood cells in the blood is elevated, this is also a possible symptom of the disease - polycythemia. This is a tumor process that is quite difficult and is much more difficult to treat than anemia.

Also, according to the analysis, it is possible to identify atypical forms of red blood cells, which also affect their functions. For example, they reduce the lifespan of a cell.

Hemoglobin

It happens that the number of red blood cells does not change, but signs of anemia are still present. Most often, this indicates that there is not enough hemoglobin in red blood cells - a component that is responsible for the attachment of oxygen atoms. Therefore, in a blood test, the determination of the amount of this protein is highlighted in a separate item. Since it is hemoglobin that makes erythrocytes red, the color factor is taken into account when decoding blood - the protein content can be determined by the color saturation.

Platelet count

Platelets provide normal blood clotting, and their low level, thrombocytopenia, is a direct threat to human life. Indeed, with such a disease, a small wound can cause massive blood loss. Against the background of a low level of platelets, the condition of the walls of blood vessels may deteriorate - they lose elasticity, become fragile. If the level of platelets in the blood is elevated, this can lead to the formation of blood clots, blockage of small vessels and such consequences as the development of necrosis, including the development of kidney, myocardial, and brain cells.

White blood cell count

Leukocytes are responsible for immunity, and their low level (leukopenia) threatens with dangerous health consequences. With a slight deviation from the norm, the patient is more susceptible to infections, often suffers from seasonal illnesses, it can be more difficult to endure illnesses, and get complications. Leukopenia can manifest itself against the background of drug treatment, it often accompanies infectious diseases such as measles, rubella. In such cases, the level of leukocytes is restored after treatment. However, a low level of these blood components may indicate serious diseases: tuberculosis, malignant tumors, damage to the bone marrow, and the presence of HIV infection.

Leukocytosis (elevated white blood cell count) can be a sign of severe inflammation. Blood in children may contain an increased number of leukocytes, which is normal and does not affect well-being.

Some indicators are not directly related to blood diseases, but they strongly affect the functioning of the cardiovascular system and other organs involved in the blood circulation process.

High cholesterol in the blood

A blood test for cholesterol is taken to determine the risk of developing atherosclerosis or coronary heart disease. It is advisable to carry out such an examination once a year, in complex preventive diagnostics by a cardiologist. By itself, this lipid is not dangerous, because it helps the arteries to maintain the elasticity and integrity of the walls. However, this applies to the so-called "good" cholesterol - HDL. But another indicator, LDL, can lead to its adhesion to the walls of blood vessels and the formation of plaques, which narrow the lumen of the artery. Blood test is normal for total cholesterol - 3.6-7.8 mmol / l.

Bilirubin is elevated in the blood

Bilirubin is formed as a result of the destruction of hemoglobin. It is a yellow blood pigment, an increase in the level of which gives jaundice - one of the important symptoms of liver cell damage. Moreover, the severity of the disease can be different. For example, an increase in bilirubin is noted in ordinary poisoning, but it may also indicate cirrhosis, hepatitis, and even an oncological process.

Allocate direct bilirubin, which appears in the blood when the outflow of bile is disturbed, and indirect - the result of increased breakdown of erythrocytes. The liver is an important organ for blood, since the largest supply of its deposited component is stored here.

Blood norm for bilirubin:

• General - 3.4-17.1 μmol / L.
• Direct - 0-7.9 μmol / L.
• Indirect - up to 19 μmol / L.

Increased creatinine in the blood

Creatinine is a metabolite, the end product of the breakdown of metabolic processes that occur in muscles. And although its small amount is always in plasma, the main percentage is excreted by the kidneys. If creatinine is elevated in the blood, this indicates the possible development, in particular, of renal failure. Also, a high concentration of the metabolite indicates possible muscle problems. However, only a doctor can correctly decipher a blood test, since creatinine easily rises and falls from physical activity, the use of certain foods, and even against a background of stress.

The kidneys are extremely important for the normal state of blood, since this is where it is filtered. Healthy kidneys can process 1,700 liters of blood per day, that is, in about 3 minutes, its entire total volume passes through them. In the event that the kidneys do not cope with their functions, the blood becomes polluted, decay products begin to circulate through the circulatory system and can harm other organs.

Blood norm for creatinine:

• Men - 62-115 μmol / L.
• Women - 53-97 μmol / l.

Blood sugar

Checking glucose levels is the main way to diagnose diabetes. With an increase in blood sugar, the risk of developing CVD diseases significantly increases. Including myocardial infarction, which against the background of type 1 diabetes can occur even in childhood. There is also a danger of overlapping peripheral vessels, and this in turn leads to suppuration, ulcers and even loss of limbs. Too low blood sugar affects the general condition, hypoglycemia develops, which, without medical assistance, leads to coma and death.

Today, blood sugar testing is one of the simplest. Diabetics control this indicator using home blood glucose meters, which give a result in less than a minute. Healthy people are recommended to undergo such an analysis at least once a year. Deciphering a blood test depends on many factors, in particular, the last meal is taken into account.

Normal fasting glucose:

• Children under 14 years old - 3.33-5.55 mmol / l.
• Adults - 3.89-5.83 mmol / L.
• Elderly people - 4.44-6.38 mmol / l.

The most common blood disease is anemia (anemia), which is characterized by a decrease in hemoglobin / red blood cells. The reasons for the lack of this protein can be caused by various factors. The most common form is iron deficiency, triggered by a lack or poor absorption of iron. The most serious types of anemias are associated with disruption of the bone marrow and pathology of formed elements: hemolytic is caused by the rapid destruction of erythrocytes, aplastic is caused by inhibition of growth or complete cessation of the production of blood cells. Posthemorrhagic anemias are distinguished as a separate type, developing against the background of different types of blood loss, including internal hemorrhages.

However, despite the different ethology of diseases, they pose a similar danger - oxygen starvation of the body and the consequences caused by it. According to the severity, there are three stages of anemia:

1. Light (hemoglobin above 90 g / l).
2. Medium (90-70 g / l).
3. Heavy (less than 70 g / l).

The most severe forms require treatment with blood transfusion, and if anemia is caused by pathologies or diseases of the bone marrow, then blood transfusions are carried out in a course.

Iron-deficiency anemia

Among all diagnosed anemias, iron deficiency is in the first place. The fact is that most often it develops not against the background of pathology, but as a result of improper nutrition. Low levels of hemoglobin in the blood can manifest itself in vegetarians, people living far from the sea, people who often follow strict diets.

Iron deficiency anemia also develops when the body needs an increased intake of iron. An example would be during pregnancy and menstruation.

Mild anemia caused by lifestyle is regulated without the use of medication, but with the help of dietary adjustments. The following foods are introduced into the diet:

• Meat, liver.
• Fish, seafood.
• Green vegetables.
• Legumes (soybeans, lentils, peas).
• Apples.

In rare cases, the level of iron in the blood drops due to the fact that the body simply cannot absorb this element. The cause is various diseases of the gastrointestinal tract, in particular, atrophic gastritis, inflammatory diseases, scar processes in the small intestine. In this case, the treatment of anemia will be aimed at eliminating the main cause of anemia.

B12 deficiency anemia

The second most common anemia is caused by a lack of vitamin B12. First of all, it is necessary for the nervous system, but it also affects the bone marrow - with its deficiency, the production of red blood cells slows down. Anemia develops very slowly, often becomes chronic with constant relapses. Unlike iron deficiency anemia, the main reason for the development of this form of anemia is just a violation of the absorption of vitamin B12. Therefore, treatment is aimed primarily at eliminating gastrointestinal diseases.

This blood disease manifests itself with the following symptoms:

• Unsteadiness of gait.
• General weakness.
• Numbness and tingling in the fingers.
• Swelling of the extremities.
• Burning and itching at the tip of the tongue.

Hemolytic anemia

Hemolytic anemias are associated with the rapid destruction of red blood cells - there is not enough hemoglobin in the blood, because the cells containing it simply do not have time to reproduce. Normally, red blood cells live for about 120 days, with some types of such anemias, they can die already on the 12-14th day. Considering that hemoglobin is rapidly destroyed, the patient may develop jaundice against the background of general symptoms, and in the biochemical blood test, bilirubin, a breakdown product of hemoglobin, will necessarily be increased.

One of the reasons for such a short life of erythrocytes can be their irregular shape. So, sickle cell anemia is distinguished by elongated cells, pointed at the ends. These red blood cells cannot function normally and are quickly destroyed. In addition, the abnormal shape of blood cells can lead to the fact that they block the blood vessels.

Another type of hemolytic anemia is caused by an autoimmune reaction. With it, red blood cells are destroyed by the cells of their own body, which perceive red blood cells as foreign elements.

Aplastic anemia

Aplastic anemia occurs as a result of a malfunction of the bone marrow, which, for various reasons, cannot produce blood cells. It differs from previous forms of anemia in that not only erythrocytes are affected, but also leukocytes and platelets. Previous infections, radiation or heredity can lead to such violations. Aplastic forms of anemia are rare, easily determined by a general blood test, where all the uniform components are indicated.

Hemophilia

Hemophilia is a blood clotting disorder, but its causes are not inadequate platelet production, but plasma abnormalities. In a liquid medium, there is a reduced level or absence of blood coagulation protein VIII (Factor VIII). If such a deviation is detected when decoding a blood test, hemophilia A, or classic hemophilia, is diagnosed. There is also B, but it accounts for only 20% of all cases of this pathology. Both diseases are hereditary, and not only the type, but also the severity of the disease is transmitted to the descendants. Symptoms appear exclusively in men, but only women are carriers, since the disease is associated with a change in a gene on the X chromosome.

In hemophilia A, the bleeding may not heal at first because the platelets that block the wound are working normally. But after a day, blood may start pouring out of the damaged area, and in some cases it is impossible to stop it for months. Particularly dangerous in this regard are small internal bleeding, which the patient may simply not notice for a long time.

The main blood test for diagnosing hemophilia is the clotting factor, which not only shows the presence of the disease, but also its severity.

The disease is congenital and chronic, therefore the patient is prescribed replacement therapy with antihemophilic globulin concentrates for life. This treatment can completely relieve the symptoms of hemophilia. However, it should be started as soon as possible, since constant bleeding can affect the health of joints, muscles, and internal organs.

Leukemias are a group of oncological blood diseases in which cancer cells copy the bone marrow or produce altered blood cells. In the first case, the degeneration of the bone marrow tissue leads to the fact that it cannot produce sufficient erythrocytes, leukocytes and platelets. In the second, cancer cells gradually replace healthy ones in the total blood mass.

The reasons for this degeneration are not fully understood, but it is directly associated with impaired immunity. For the development of the disease, one stem cell is enough, which begins to produce pathologically altered shaped elements.

Leukemias are acute and chronic. The former are very difficult and require immediate treatment. By type, these are different diseases, since they are associated with the formation of different types of cancer cells. Therefore, acute leukemia cannot become chronic, and vice versa.

At the initial stage, the symptoms of blood cancer are similar to ARVI:

• Temperature increase.
• Body aches.
• Pallor.
• Dizziness.
• Red spots may appear as a result of subcutaneous hemorrhage.

The disease is diagnosed by general and biochemical blood tests, as well as bone marrow studies. The patient is prescribed chemotherapy, and if it does not help, a bone marrow transplant.

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✪ What is blood made of

✪ Internal environment of the body. Composition and function of blood. Biology video tutorial grade 8

✪ BTS "Blood Sweat & Tears" mirrored Dance Practice

Subtitles

I do not like to do this, but from time to time I need to donate blood. The thing is, I'm afraid to do it, just like a small child. I really do not like injections. But, naturally, I force myself. I donate blood and try to distract myself while the blood fills the needle. Usually I turn away and everything goes quickly and almost imperceptibly. And I leave the clinic absolutely happy, because everything is over and I no longer need to think about it. Now I want to trace the path that makes the blood after it was taken. At the first stage, the blood enters the test tube. This happens directly on the day of blood sampling. Usually such a test tube is ready and waiting for blood to be poured into it. This is the lid of my test tube. Draw blood inside the test tube. Full tube. This is not a simple test tube, its walls are coated with a chemical that prevents blood from clotting. Blood clotting should not be allowed, as this will extremely difficult to further study it. That is why a special test tube is used. The blood will not clot in it. To make sure that everything is in order with her, the test tube is shaken slightly, checking the density of the sample .. Now the blood enters the laboratory. There is a special apparatus in the laboratory, into which my blood and the blood of other people who visited the clinic that day gets. All our blood is labeled and delivered to the machine. And what does the apparatus do? It spins quickly. Spins really fast. All test tubes are fixed, they will not fly away, and, accordingly, they rotate in this apparatus. By rotating the tubes, the apparatus creates a force called "centrifugal force". And the whole process is called "centrifugation". Let me write it down. Centrifugation. And the apparatus itself is called a centrifuge. Blood tubes rotate in either direction. And as a result, the blood begins to separate. The heavy particles move to the bottom of the tube, while the less dense part of the blood rises to the cap. After the blood in the tube has been centrifuged, it will look like this. Now I will try to portray this. Let it be a test tube before rotating. Before rotation. And this is a test tube after rotation. This is her view after. So what does a centrifuge tube look like? The key difference will be that instead of the homogeneous liquid that we had, we get an outwardly completely different liquid. Three different layers are distinguishable, which I will now draw for you. So, this is the first layer, the most impressive, making up most of our blood. He is up here. It has the lowest density, which is why it stays near the lid. In fact, it makes up almost 55% of the total blood volume. We call it plasma. If you've ever heard the word plasma, now you know what it means. Let's take a drop of plasma and try to find out its composition. 90% of plasma is just water. Interesting isn't it. Just water. Most of the blood is plasma and most of it is water. Most of the blood is plasma, most of the plasma is water. This is why people are told, "Drink plenty of water to stay hydrated" since most of the blood is water. This is true for the rest of the body, but in this case I am focusing on blood. So what is left? We already know that 90% of plasma is water, but that's not 100%. 8% of plasma is protein. Let me show you some examples of such a protein. This is albumin. Albumin, if you are unfamiliar with it, is an important plasma protein that makes it impossible for blood to drain from blood vessels. Another important protein is the antibody. I'm sure you've heard of it, antibodies are linked to our immune system. They make sure that you are beautiful and healthy, and do not suffer from infections. And another type of protein to keep in mind is fibrinogen. Fibrinogen. He takes a very active part in blood clotting. Of course, in addition to it, there are other coagulation factors. But about them - a little later. We have listed proteins: albumin, antibody, fibrinogen. But we still have 2%, they are substances such as hormones, insulin, for example. It also contains electrolytes. For example sodium. Also, this 2% includes nutrients. Such as glucose, for example. All these substances make up our plasma. Many of the substances we talk about when we talk about blood are found in plasma, including vitamins and similar substances. Now let's take a look at the next layer, which is directly under the plasma and highlighted in white. This layer makes up a very small part of the blood. Less than 1%. And it is formed by white blood cells, as well as platelets. Platelets. These are the cellular parts of our blood. There are very few of them, but they are very important. Under this layer is the densest layer - red blood cells. This is the last layer, and its proportion will be approximately 45%. Here they are. Red blood cells, 45%. These are red blood cells that contain hemoglobin. It should be noted here that not only does plasma contain proteins (which we mentioned at the beginning of the video), white and red blood cells also contain a very large amount of proteins, which should not be forgotten. Hemoglobin is an example of such a protein. Now serum is the word you've probably heard. What is it? Serum is essentially the same as plasma. Now I will circle everything that is included in the serum. Everything circled in blue is serum. I did not include fibrinogen and clotting factors in the serum. So, plasma and serum are very similar except that there is no fibrinogen or clotting factors in the serum. Let's look at the red blood cells now, what can we learn? You may have heard a word like hematocrit. So the hematocrit is 45% of the blood volume in this figure. This means that the hematocrit is equal to the volume occupied by red blood cells divided by the total volume. In this example, the total volume is 100%, the red blood cell volume is 45%, so I know that the hematocrit volume would be 45%. It's just the percentage that red blood cells make up. And it is very important to know it, since red blood cells carry oxygen. In order to emphasize the meaning of hematocrit, and also to introduce some new words, I will draw three small tubes of blood. Let's say I have three tubes: one, two, three. They contain the blood of different people. But these people are of the same sex and age, since the amount of hematocrit depends on age, gender, and even on what altitude you live above sea level. If you live on a mountain top, your hematocrit will differ from the hematocrit of the plains. Many factors affect the hematocrit. We have three people who are very similar in these factors. The blood plasma of the first person, I will draw it here, occupies such a part of the total blood volume. Plasma of the second occupies just such a part of the total blood volume. And the plasma of the third occupies the largest part of the total blood volume, say, the entire volume to the bottom. So you ran through all three tubes and this is what you got. Of course, all three have white blood cells, I will draw them. And everyone has platelets, we said that this is a thin layer of less than 1%. And the remainder is made up of red blood cells. This is a layer of red blood cells. The second person has a lot of them. And the third has the least. Red blood cells do not occupy a large part of the total volume. So, if I needed to assess the state of these three people, I would say that the first person is doing well. The second has a lot of red blood cells. They are numerically predominant. We see a really high percentage of red blood cells. Really big. So I can conclude that this person has polycythemia. Polycythemia is a medical term meaning that the number of red blood cells is very high. In other words, he has an elevated hematocrit. And this third person has a very low number of red blood cells in relation to the total volume. Conclusion - he has anemia. If now you hear the term "anemia", or "polycythemia", you will know that we are talking about how much of the total blood volume is occupied by red blood cells. See you in the next video. Subtitles by the Amara.org community

Blood properties

• Suspension properties depend on the protein composition of blood plasma, and on the ratio of protein fractions (normally there are more albumin than globulins).
• Colloidal properties associated with the presence of proteins in plasma. Due to this, the constancy of the liquid composition of the blood is ensured, since protein molecules have the ability to retain water.
• Electrolyte properties depend on the content of anions and cations in blood plasma. The electrolyte properties of blood are determined by the osmotic pressure of the blood.

Blood composition

The entire blood volume of a living organism is conditionally divided into peripheral (located and circulating in the vascular bed) and blood located in the hematopoietic organs and peripheral tissues. Blood has two main components: plasma and weighed in it shaped elements... The settled blood consists of three layers: the upper layer is formed by yellowish blood plasma, the middle, relatively thin gray layer is made up of leukocytes, the lower red layer is formed by erythrocytes. In an adult healthy person, the plasma volume reaches 50-60% of whole blood, and blood cells make up about 40-50%. The ratio of blood cells to its total volume, expressed as a percentage or represented as a decimal fraction accurate to hundredths, is called the hematocrit number (from ancient Greek. αἷμα - blood, κριτός - indicator) or hematocrit (Ht). Thus, hematocrit is a part of the blood volume attributable to erythrocytes (sometimes defined as the ratio of all formed elements (erythrocytes, leukocytes, platelets) to the total blood volume). Determination of hematocrit is carried out using a special graduated glass tube - hematocrit, which is filled with blood and centrifuged. After that, it is noted what part of it is occupied by the formed elements of the blood (leukocytes, platelets and erythrocytes). In medical practice, the use of automatic hematological analyzers is increasingly spreading to determine the hematocrit index (Ht or PCV).

Plasma

Shaped elements

In an adult, blood corpuscles make up about 40-50%, and plasma - 50-60%. Corpuscular elements of blood are presented erythrocytes, platelets and leukocytes:

• Erythrocytes ( red blood cells) are the most numerous of the shaped elements. Mature erythrocytes do not contain a nucleus and are shaped like biconcave discs. They circulate for 120 days and are destroyed in the liver and spleen. Erythrocytes contain an iron-containing protein - hemoglobin. It provides the main function of erythrocytes - the transport of gases, primarily oxygen. It is hemoglobin that gives the blood a red color. In the lungs, hemoglobin binds oxygen, turning into oxyhemoglobin which is light red in color. In tissues, oxyhemoglobin releases oxygen, forming hemoglobin again, and the blood darkens. In addition to oxygen, hemoglobin in the form of carbohemoglobin transfers carbon dioxide from the tissues to the lungs.

Blood is required for victims of burns and injuries as a result of massive bleeding: during complex operations, in the process of difficult and complicated childbirth, and for patients with hemophilia and anemia - to maintain life. Blood is also vital for cancer patients during chemotherapy. Every third inhabitant of the Earth needs donor blood at least once in his life.

Blood taken from a donor (donor blood) is used for research and educational purposes; in the production of blood components, medicines and medical devices. The clinical use of donated blood and (or) its components is associated with transfusion (transfusion) to the recipient for therapeutic purposes and the creation of stocks of donor blood and (or) its components.

Diseases of the blood

• Anemia (Greek. αναιμία anemia) - a group of clinical and hematological syndromes, the common point for which is a decrease in the concentration of hemoglobin in the circulating blood, more often with a simultaneous decrease in the number of erythrocytes (or the total volume of erythrocytes). The term "anemia" without detailing does not define a specific disease, that is, anemia should be considered one of the symptoms of various pathological conditions;
• Hemolytic anemia - increased destruction of red blood cells;
• Hemolytic disease of the newborn (HDN) is a pathological condition of the newborn, accompanied by massive breakdown of erythrocytes, in the process of hemolysis caused by an immunological conflict between the mother and the fetus as a result of the incompatibility of the blood of the mother and the fetus by blood group or Rh factor. Thus, the blood cells of the fetus become foreign agents (antigens) for the mother, in response to which antibodies are produced that penetrate the blood-placental barrier and attack the erythrocytes of the fetal blood, as a result of which, in the first hours after birth, the child begins massive intravascular hemolysis of erythrocytes. It is one of the main causes of the development of jaundice in newborns;
• Hemorrhagic disease of newborns - coagulopathy that develops in a child between 24 and 72 hours of life and is often associated with a lack of vitamin K, due to the deficiency of which there is a lack of biosynthesis in the liver of coagulation factors II, VII, IX, X, C, S. Treatment and prevention consists adding vitamin K to the diet of newborns soon after birth;
• Hemophilia - low blood clotting;
• Disseminated intravascular blood coagulation - the formation of microthrombi;
• Hemorrhagic vasculitis ( allergic purpura) - the most common disease from the group of systemic vasculitis, which is based on aseptic inflammation of the walls of microvessels, multiple microthrombosis, affecting the vessels of the skin and internal organs (most often the kidneys and intestines). The main reason causing the clinical manifestations of this disease is the circulation of immune complexes and activated components of the complement system in the blood;
• Idiopathic thrombocytopenic purpura ( Werlhof's disease) - a chronic wave-like disease, which is a primary hemorrhagic diathesis due to quantitative and qualitative insufficiency of the platelet hemostasis;
• Hemoblastosis is a group of neoplastic blood diseases, conditionally divided into leukemic and non-leukemic:
  • Leukemia (leukemia) is a clonal malignant (neoplastic) disease of the hematopoietic system;
• Anaplasmosis is a form of blood disease in domestic and wild animals, carried by ticks of the genus Anaplasma (lat.Anaplasma) of the lat. Ehrlichiaceae.

Pathological conditions

• Hypovolemia - a pathological decrease in the volume of circulating blood;
• Hypervolemia - a pathological increase in the volume of circulating blood;

The chemical composition of blood in a healthy person is unchanged. Even if some shifts occur, the balance of chemical components is quickly leveled using regulatory mechanisms. This is important for maintaining the normal functioning of all organs and tissues of the body. If the chemical composition of the blood changes markedly, this indicates a serious pathology, therefore, the most common diagnostic method for any disease is.

A large number of organic compounds are found in human whole blood and plasma: proteins, enzymes, acids, lipids, lipoproteins, etc. All organic substances in human blood are divided into nitrogenous and nitrogen-free. Nitrogen contains some proteins and amino acids, and does not contain -, fatty acids.

The chemical composition of human blood is determined by organic compounds by about 9%. Inorganic compounds make up no more than 3% and about 90% - water.

Organic blood compounds:

• ... It is a blood protein that is responsible for blood clots. It is he who allows the formation of blood clots, clots that stop bleeding if necessary. If there is damage to tissues, blood vessels, the level of fibrinogen rises and rises. This protein is included in the composition. Its level rises significantly before childbirth, which helps prevent bleeding.
• ... It is a simple protein found in human blood. Blood tests usually indicate serum albumin. The liver is responsible for its production. This type of albumin is found in blood serum. It accounts for more than half of all plasma proteins. The main function of this protein is to transport substances that are poorly soluble in the blood.
• ... When, under the influence of various enzymes, protein compounds in the blood are destroyed, uric acid begins to be released. It is excreted from the body through the intestines and kidneys. It is uric acid that accumulates in the body that can cause a disease called gout (inflammation of the joints).
• ... It is an organic compound in the blood that is part of the membranes of tissue cells. Cholesterol plays an important role as a building block of cellular material, and its level must be maintained. However, with an increased content of it, cholesterol plaques can form, causing blockage of blood vessels and arteries.
• Lipids. Lipids, that is, fats, and their compounds perform an energetic function. They provide the body with energy, participate in various reactions, metabolism. Most often, when speaking of lipids, they mean cholesterol, but there are other varieties (high and low density lipids).
• Creatinine. Creatinine is a substance produced by chemical reactions in the blood. It is formed in the muscles and participates in energy metabolism.

Electrolyte composition of human blood plasma

Electrolytes are mineral compounds that have very important functions.

Human contains about 90% of water, which contains dissolved organic and inorganic components. The electrolyte composition of blood is the ratio of cations and anions, which are neutral in total.

Important components:

• Sodium. Sodium ions are also found in blood plasma. A large amount of sodium in the blood leads to edema and accumulation of fluid in the tissues, and a lack of it leads to dehydration. Sodium also plays an important role in muscle and nervous excitability. The simplest and most readily available source of sodium is regular table salt. The required amount of sodium is absorbed in the intestines, and the excess is excreted by the kidneys.
• Potassium. Potassium is found in greater quantities in cells than in the intercellular space. There is not much of it in the blood plasma. It is excreted by the kidneys and is controlled by adrenal hormones. An increased level of potassium is very dangerous for the body. This condition can lead to respiratory arrest and shock. Potassium is responsible for the conduction of nerve impulses in the muscle. With its lack, heart failure can develop, since the heart muscle loses its ability to contract.
• Calcium. Plasma contains ionized and non-ionized calcium. Calcium performs many important functions: it is responsible for nervous excitability, the ability of blood to coagulate, and is part of the bone tissue. Calcium is also excreted from the body by the kidneys. Both high and low blood calcium levels are difficult for the body to tolerate.
• Magnesium. Most of the magnesium in the human body is concentrated inside cells. Much more of this substance is found in muscle tissue, but it is also present in blood plasma. Even if the level of magnesium in the blood decreases, the body replenishes it from the muscle tissue.
• Phosphorus. Phosphorus is present in the blood in various forms, but inorganic phosphate is most commonly considered. A decrease in the level of phosphorus in the blood often leads to rickets. Phosphorus plays an important role in energy metabolism, the preservation of nervous excitability. Lack of phosphorus may not appear. In rare cases, severe deficiency causes muscle weakness and impaired consciousness.
• ... In the blood, iron is mainly contained in erythrocytes, in blood plasma its small amount. During the synthesis of hemoglobin, iron is actively consumed, and when it breaks down, it is released.

Revealing the chemical composition of blood is called. At the moment, this analysis is the most versatile and informative. Any examination begins with it.

A biochemical blood test allows you to assess the work of all organs and systems of the body. The indicators of the biochemical blood test include proteins, lipids, enzymes, blood cells, and the electrolyte composition of blood plasma.

The diagnostic procedure can be divided into 2 stages: preparation for the analysis and the blood sampling itself. Preparatory procedures are very important as they help reduce the likelihood of errors in the analysis results. Despite the fact that the composition of the blood is fairly constant, the blood counts react to any effect on the body. For example, blood counts can change under stress, overheating, vigorous physical activity, unhealthy diet and exposure to certain drugs.

If the rules for preparing for a biochemical blood test were violated, errors may result from the tests.

An abundance of fats in the blood causes the blood serum to clot too quickly and becomes unusable for analysis.Blood is taken on an empty stomach and preferably in the morning. It is not recommended to eat or drink anything 8-10 hours before the test, except for pure non-carbonated water.

Useful video - Biochemical blood test:

If some indicators are deviated, it is advisable to repeat the blood test in order to exclude the possibility of error.Blood sampling is carried out in the laboratory by medical staff. Blood is drawn from a vein. At the same time, the patient can sit or lie down if he does not tolerate the procedure well. The patient's forearm is pulled with a tourniquet, and blood is drawn from a vein at the bend of the elbow using a syringe or a special catheter. The blood is collected in a test tube and transferred to the laboratory for microscopic examination.

The entire blood sampling procedure takes no more than 5 minutes. It is fairly painless when done by an experienced professional. The results are given to the patient the next day. Decryption should be dealt with by a doctor. All blood counts are assessed together. A deviation in a single indicator may be the result of an error.

Norm and deviation from the norm

Each indicator has its own norm. A deviation from the norm can be a consequence of physiological reasons, as well as pathological conditions. The more the indicator deviates from the norm, the higher the likelihood of a pathological process in the body.

Decoding LHC:

• ... Normally, hemoglobin in an adult should be more than 120 g / l. This protein is responsible for transporting oxygen to organs and tissues. A decrease in the level of hemoglobin indicates oxygen starvation and, a pathological excess (more than 200 g / l) - a lack of certain vitamins in the body.
• Albumen. This protein should be present in the blood in an amount of 35-52 g / l. If the level of albumin rises, then the body for some reason suffers from dehydration, if the level goes down, then there may be problems with the kidneys and intestines.
• Creatinine. Since this substance is formed in the muscles, in men, the norm is slightly higher than in women (from 63 mmol / l, while in women - from 53). Elevated creatinine levels indicate an excessive intake of protein foods, heavy muscle work, or muscle breakdown. The level of creatinine is lowered with dystrophy of muscle mass.
• Lipids. As a rule, the most important indicator is the level. Total cholesterol in the blood of a healthy person is present in the amount of 3-6 mmol / l. Elevated cholesterol levels are among the risk factors for cardiovascular diseases and heart attacks.
• Magnesium. The norm of magnesium in the blood is 0.6 - 1.5 mmol / l. Magnesium deficiency occurs as a result of malnutrition or disruption of the intestines and leads to convulsive syndrome, muscle dysfunction, and chronic fatigue.
• Potassium. Potassium is present in the blood of a healthy person in an amount of 3.5-5.5 mmol / l. Various injuries, operations, tumors, hormonal disruptions can lead to hyperkalemia. With an increased content of potassium in the blood, muscle weakness occurs, a malfunction of the heart, in severe cases, hyperglycemia leads to paralysis of the respiratory muscles.

A blood test reveals abnormalities in the work of certain organs, but the diagnosis is usually made after further examination. For this reason, you should not diagnose yourself on your own; it is better to entrust the decoding of the analysis results to the doctor.

Definition of the concept of the blood system

Blood system(according to G.F. Lang, 1939) - a set of blood itself, hematopoietic organs, blood destruction (red bone marrow, thymus, spleen, lymph nodes) and neurohumoral mechanisms of regulation, due to which the constancy of the composition and function of blood is maintained.

Currently, the blood system is functionally supplemented with organs for the synthesis of plasma proteins (liver), delivery into the bloodstream and excretion of water and electrolytes (intestines, nights). The most important features of blood as a functional system are as follows:

• it can perform its functions only being in a liquid state of aggregation and in constant motion (along the blood vessels and cavities of the heart);
• all its constituent parts are formed outside the vascular bed;
• it unites the work of many physiological systems of the body.

The composition and amount of blood in the body

Blood is a liquid connective tissue, which consists of a liquid part - and cells suspended in it - : (red blood cells), (white blood cells), (platelets). In an adult, blood corpuscles are about 40-48%, and plasma - 52-60%. This ratio is called the hematocrit number (from the Greek. haima- blood, kritos- index). The composition of the blood is shown in Fig. 1.

Rice. 1. Composition of blood

The total amount of blood (how much blood) in the body of an adult is normally 6-8% of body weight, i.e. about 5-6 liters.

Physicochemical properties of blood and plasma

How much blood is in the human body?

The share of blood in an adult is 6-8% of the body weight, which corresponds to approximately 4.5-6.0 liters (with an average weight of 70 kg). In children and athletes, the blood volume is 1.5-2.0 times greater. In newborns, it is 15% of the body weight, in children of the 1st year of life - 11%. In humans, under conditions of physiological rest, not all blood actively circulates through the cardiovascular system. Part of it is located in blood depots - venules and veins of the liver, spleen, lungs, skin, in which the blood flow rate is significantly reduced. The total amount of blood in the body is kept at a relatively constant level. Rapid loss of 30-50% of blood can lead to death of the body. In these cases, urgent transfusion of blood products or blood substitute solutions is required.

Blood viscosity due to the presence of shaped elements in it, primarily erythrocytes, proteins and lipoproteins. If the viscosity of water is taken as 1, then the viscosity of the whole blood of a healthy person will be about 4.5 (3.5-5.4), and that of plasma - about 2.2 (1.9-2.6). The relative density (specific gravity) of the blood depends mainly on the number of red blood cells and the protein content in the plasma. In a healthy adult, the relative density of whole blood is 1.050-1.060 kg / l, erythrocyte mass - 1.080-1.090 kg / l, blood plasma - 1.029-1.034 kg / l. For men, it is slightly higher than for women. The highest relative density of whole blood (1.060-1.080 kg / l) is observed in newborns. These differences are explained by the difference in the number of red blood cells in the blood of people of different sex and age.

Hematocrit indicator- a part of the blood volume attributable to the proportion of formed elements (first of all, erythrocytes). Normally, the hematocrit of the circulating blood of an adult is on average 40-45% (for a husband - a chip - 40-49%, for women - 36-42%). In newborns, it is approximately 10% higher, and in young children, it is approximately the same amount lower than in an adult.

Blood plasma: composition and properties

The osmotic pressure of blood, lymph and tissue fluid determines the exchange of water between blood and tissues. A change in the osmotic pressure of the fluid surrounding the cells leads to a violation of their water exchange. This can be seen on the example of erythrocytes, which in a hypertonic solution of NaCl (a lot of salt) lose water and shrink. In a hypotonic solution of NaCl (little salt), erythrocytes, on the contrary, swell, increase in volume and may burst.

The osmotic pressure of the blood depends on the salts dissolved in it. About 60% of this pressure is generated by NaCl. The osmotic pressure of blood, lymph and interstitial fluid is approximately the same (approximately 290-300 mosm / l, or 7.6 atm) and is constant. Even in cases where a significant amount of water or salt enters the blood, the osmotic pressure does not undergo significant changes. With an excessive intake of water into the blood, water is rapidly excreted by the kidneys and passes into the tissues, which restores the original value of osmotic pressure. If the concentration of salts in the blood increases, then water from the tissue fluid passes into the vascular bed, and the kidneys begin to intensively remove salt. The products of digestion of proteins, fats and carbohydrates, absorbed into the blood and lymph, as well as low-molecular products of cellular metabolism, can change the osmotic pressure within small limits.

Maintaining a constant osmotic pressure plays a very important role in the vital activity of cells.

Concentration of hydrogen ions and regulation of blood pH

The blood has a slightly alkaline medium: the arterial blood pH is 7.4; The pH of venous blood due to the high content of carbon dioxide in it is 7.35. Inside the cells, the pH is slightly lower (7.0-7.2), which is due to the formation of acidic products in them during metabolism. The extreme limits of pH changes, compatible with life, are values ​​from 7.2 to 7.6. A shift in pH beyond these limits causes severe disturbances and can lead to death. In healthy people, it ranges from 7.35 to 7.40. Long-term displacement of pH in humans, even by 0.1 -0.2, can be fatal.

So, at pH 6.95, loss of consciousness occurs, and if these shifts are not eliminated in the shortest possible time, then a lethal outcome is inevitable. If the pH becomes equal to 7.7, then the most severe convulsions (tetany) occur, which can also lead to death.

In the process of metabolism, tissues are released into the tissue fluid, and therefore into the blood, "acidic" metabolic products, which should lead to a shift in pH towards the acidic side. So, as a result of intense muscular activity, up to 90 g of lactic acid can enter the human blood within a few minutes. If this amount of lactic acid is added to the volume of distilled water equal to the volume of circulating blood, then the concentration of ions in it will increase 40,000 times. The reaction of the blood under these conditions practically does not change, which is explained by the presence of blood buffer systems. In addition, the pH in the body is maintained due to the work of the kidneys and lungs, which remove carbon dioxide, excess salts, acids and alkalis from the blood.

Constant blood pH is maintained buffer systems: hemoglobin, carbonate, phosphate and plasma proteins.

Hemoglobin buffer system the most powerful. It accounts for 75% of the buffer capacity of the blood. This system consists of reduced hemoglobin (HHb) and its potassium salt (KHb). Its buffering properties are due to the fact that with an excess of H +, KHb gives up K + ions, and itself attaches H + and becomes a very weakly dissociating acid. In tissues, the blood hemoglobin system performs the function of an alkali, preventing blood acidification due to the entry of carbon dioxide and H + ions into it. In the lungs, hemoglobin behaves like an acid, preventing the blood from alkalizing after the release of carbon dioxide from it.

Carbonate buffer system(Н 2 СО 3 and NaHCO 3) in terms of its power takes the second place after the hemoglobin system. It functions as follows: NaHCO 3 dissociates into Na + and HCO 3 - ions. When a stronger acid than carbonic acid enters the blood, an exchange reaction of Na + ions occurs with the formation of weakly dissociating and easily soluble H2CO3. Thus, an increase in the concentration of H + ions in the blood is prevented. An increase in the content of carbonic acid in the blood leads to its decay (under the influence of a special enzyme found in erythrocytes - carbonic anhydrase) into water and carbon dioxide. The latter enters the lungs and is released into the environment. As a result of these processes, the entry of acid into the blood leads to only a slight temporary increase in the content of neutral salt without a shift in pH. In the case of alkali entering the blood, it reacts with carbonic acid, forming bicarbonate (NaHCO 3) and water. The resulting deficiency of carbonic acid is immediately compensated for by a decrease in the release of carbon dioxide from the lungs.

Phosphate buffer system formed by sodium dihydrogen phosphate (NaH 2 P0 4) and sodium hydrogen phosphate (Na 2 HP0 4). The first compound weakly dissociates and behaves like a weak acid. The second compound is alkaline. When a stronger acid is introduced into the blood, it reacts with Na, HP0 4, forming a neutral salt and increasing the amount of little dissociating sodium dihydrogen phosphate. If a strong alkali is introduced into the blood, it interacts with sodium dihydrogenphosphate, forming a weakly alkaline sodium hydrogenphosphate; In this case, the pH of the blood changes insignificantly. In both cases, excess dihydrogen phosphate and sodium hydrogen phosphate are excreted in the urine.

Plasma proteins play the role of a buffer system due to their amphoteric properties. In an acidic environment, they behave like alkalis, binding acids. In an alkaline environment, proteins react like acids that bind alkalis.

Nervous regulation plays an important role in maintaining blood pH. In this case, the chemoreceptors of the vascular reflexogenic zones are mainly irritated, the impulses from which enter the medulla oblongata and other parts of the central nervous system, which reflexively includes in the reaction peripheral organs - the kidneys, lungs, sweat glands, the gastrointestinal tract, whose activity is aimed at restoring the initial pH values. So, when the pH is shifted to the acidic side, the kidneys intensively excrete the anion Н 2 Р0 4 - with urine. When the pH is reduced to the alkaline side, the excretion by the kidneys of the НР0 4 -2 and НС0 3 - anions increases. Human sweat glands are capable of removing excess lactic acid, and the lungs - CO2.

Under various pathological conditions, a shift in pH can be observed both in acidic and alkaline environments. The first of them is called acidosis, second - alkalosis.