Influence of environmental factors on the circulatory system. Presentation on "the influence of factors on the cardiovascular system"

08.06.2020

Influence of various factors on the human cardiovascular system

What are the causes of cardiovascular disease? What factors affect the work of the cardiovascular system? How can you strengthen your cardiovascular system?

Ecologists "cardiovascular disasters".

Statistics 1 million 300 thousand people die annually from diseases of the cardiovascular system, and this figure is increasing from year to year. Cardiovascular diseases account for 57% of the total mortality in Russia. About 85% of all diseases modern man associated with adverse environmental conditions arising from his own fault

Influence of the consequences of human activity on the work of the cardiovascular system It is impossible to find a place on the globe where pollutants are not present in one or another concentration. Even in the ice of Antarctica, where there are no industrial industries, and people live only at small scientific stations, scientists have discovered toxic (poisonous) substances of modern industries. They are carried here by atmospheric streams from other continents.

Influence of human activity on the work of the cardiovascular system Human economic activity is the main source of pollution of the biosphere. Gaseous, liquid and solid industrial wastes enter the natural environment. Various chemicals found in waste, getting into soil, air or water, pass along ecological links from one chain to another, eventually getting into the human body.

90% of CVS defects in children in disadvantaged ecological zones Lack of oxygen in the atmosphere causes hypoxia, changes in the heart rate Stress, noise, high-speed pace of life deplete the heart muscle Factors that negatively affect the cardiovascular system Environmental pollution with industrial waste leads to developmental pathology cardiovascular system in children Increased background radiation leads to irreversible changes in hematopoietic tissue In areas with polluted air In humans, high blood pressure

Cardiologists Out of 100 thousand people in Russia, 330 men and 154 women die from myocardial infarction every year, 250 men and 230 women die of strokes. The structure of mortality from cardiovascular diseases in Russia

The main risk factors leading to the development of cardiovascular diseases: high blood pressure; age: men over 40, women over 50; psycho-emotional stress; cardiovascular diseases in close relatives; diabetes; obesity; total cholesterol more than 5.5 mmol / l; smoking.

Heart disease congenital heart disease rheumatic diseases coronary artery disease hypertension infectious valve lesions primary lesion of the heart muscle

Overweight contributes to high blood pressure High cholesterol levels lead to loss of vascular elasticity Pathogenic microorganisms cause infectious heart disease A sedentary lifestyle leads to flabbiness of all body systems Heredity increases the likelihood of developing diseases Factors that negatively affect the cardiovascular system Frequent use of drugs poisons the heart muscle , heart failure develops

The chapter examines blood circulation at different levels of physical activity, lack and excess of oxygen, low and high temperatures of the environment, changes in gravity.

PHYSICAL ACTIVITY

Work can be dynamic, when resistance is overcome at a certain distance, and static - with isometric muscle contraction.

Dynamic work

Physical stress induces immediate reactions in various functional systems, including muscle, cardiovascular, and respiratory. The severity of these reactions is determined by the body's adaptability to physical activity and the severity of the work performed.

Heart rate. By the nature of the change in heart rate, two forms of work can be distinguished: light, non-tiring work - with the achievement of a stationary state - and hard work that causes fatigue (Fig. 6-1).

Even after the end of the work, the heart rate changes depending on the voltage applied. After light work, the heart rate returns to the initial level within 3-5 minutes; after hard work, the recovery period is much longer - with extremely heavy loads, it reaches several hours.

With hard work, blood flow and metabolism in the working muscle increases more than 20 times. The degree of changes in the indices of cardio- and hemodynamics during muscular activity depends on its power and physical fitness (adaptation) of the body (Table 6-1).

Figure: 6-1.Changes in heart rate in persons with average efficiency with light and heavy dynamic work of constant intensity

In persons trained for physical activity, myocardial hypertrophy occurs, the density of capillaries and the contractile characteristics of the myocardium increase.

The heart increases in size due to hypertrophy of cardiomyocytes. The weight of the heart in highly qualified athletes increases to 500 g (Fig. 6-2), the concentration of myoglobin increases in the myocardium, and the heart cavities increase.

The density of capillaries per unit area in a trained heart increases significantly. Coronary blood flow and metabolic processes increase in accordance with the work of the heart.

Myocardial contractility (the maximum rate of increase in pressure and ejection fraction) is markedly increased in athletes due to the positive inotropic action of sympathetic nerves.

Table 6-1.Changes in physiological indicators during dynamic work of different power in people not involved in sports (top line) and in trained athletes (bottom line)

Nature of work	Easy	Average	Submaximal	Maximum
Work power, W		50-100	100-150	150-250
Work power, W	100-150	150-200	200-350	350-500 and\u003e
Heart rate, beats / min	120-140	140-160	160-170	170-190
Heart rate, beats / min	90-120	120-140	140-180	180-210
Systolic blood volume, l / min	80-100	100-120	120-130	130-150
Systolic blood volume, l / min	80-100	100-140	140-170	170-200
Minute blood volume, l / min	10-12	12-15	15-20	20-25
Minute blood volume, l / min	8-10	10-15	15-30	30-40
Average blood pressure, mm Hg	85-95	95-100	100-130	130-150
Average blood pressure, mm Hg	85-95	95-100	100-150	150-170
Oxygen consumption, l / min	1,0-1,5	1,5-2,0	2,0-2,5	2,5-3,0
Oxygen consumption, l / min	0,8-1,0	1,0-2,5	2,5-4,5	4,5-6,5
Blood lactate, mg per 100 ml	20-30	30-40	40-60	60-100
Blood lactate, mg per 100 ml	10-20	20-50	50-150	150-300

With physical exertion, cardiac output increases due to an increase in heart rate and stroke volume, and the changes in these values \u200b\u200bare purely individual. In healthy young adults (with the exception of highly trained athletes), cardiac output rarely exceeds 25 L / min.

Regional blood flow. During physical exertion, regional blood flow significantly changes (Table 6-2). An increase in blood flow in working muscles is associated not only with an increase in cardiac output and blood pressure, but also with a redistribution of the BCC. With maximum dynamic work, blood flow in the muscles increases by 18-20 times, in the coronary vessels of the heart by 4-5 times, but decreases in the kidneys and abdominal organs.

In athletes, the end-diastolic heart volume naturally increases (3-4 times more than the stroke volume). For an ordinary person, this figure is only 2 times higher.

Figure: 6-2.Normal heart and athlete's heart. An increase in the size of the heart is associated with lengthening and thickening of individual myocardial cells. In the heart of an adult, there is approximately one capillary for every muscle cell.

Table 6-2.Cardiac output and organ blood flow in a person at rest and during physical activity of varying intensity

Absorption O 2 , *ml / (min m 2)**
	Rest	Easy	Average	Maximum
	140	400	1200	2000
Region	Blood flow, ml / min
Skeletal muscle	1200	4500	12 500	22 000
Heart				1000
Brain
Celiac	1400	1100
Renal	1100
Leather		1500	1900
Other organs
Cardiac output	5800	9500	17 500	25 000

With muscular activity, the excitability of the myocardium increases, the bioelectric activity of the heart changes, which is accompanied by a shortening of the PQ, QT intervals of the electrocardiogram. The more power of work and the lower the level of physical fitness of the body, the more changes in the electrocardiogram indicators.

With an increase in heart rate up to 200 per minute, the duration of diastole decreases to 0.10-0.11 s, i.e. more than 5 times in relation to this value at rest. In this case, filling of the ventricles occurs within 0.05-0.08 s.

Arterial pressure in humans, during muscular activity, it increases significantly. When running, causing an increase in heart rate up to 170-180 per minute, the following increases:

Systolic pressure on average from 130 to 250 mm Hg;

Average pressure - from 99 to 167 mm Hg;

Diastolic - from 78 to 100 mm Hg.

With intense and prolonged muscle activity, the rigidity of the main arteries increases due to the strengthening of the elastic frame and the increase in the tone of smooth muscle fibers. In the arteries of the muscle type, one can observe moderate hypertrophy muscle fibers.

The pressure in the central veins during muscle activity, as well as the central blood volume, increases. This is due to an increase in venous blood return with an increase in the tone of the vein walls. Working muscles act as an additional pump, which is referred to as a "muscle pump", which provides an increased (adequate) blood flow to the right heart.

The total peripheral vascular resistance during dynamic work can decrease by 3-4 times compared to the initial, non-working state.

Oxygen consumption increases by an amount that depends on the load and the efficiency of the effort expended.

With light work, a steady state is achieved when oxygen consumption and its utilization are equivalent, but this occurs only after 3-5 minutes, during which blood flow and metabolism in the muscle adapt to new requirements. Until a steady state is reached, the muscle depends on a small oxygen reserve,

which is provided by O 2 associated with myoglobin, and from the ability to extract oxygen from the blood.

With heavy muscular work, even if it is performed with constant effort, a stationary state does not occur; like heart rate, oxygen consumption is constantly increasing, reaching a maximum.

Oxygen debt. With the start of work, the need for energy increases instantly, but it takes some time to adjust the blood flow and aerobic metabolism; thus, oxygen debt arises:

With light work, the amount of oxygen debt remains constant after reaching a steady state;

With hard work, it grows until the very end of the work;

At the end of work, especially in the first minutes, the rate of oxygen consumption remains above the resting level - the oxygen debt is "paid off".

A measure of physical stress. As the intensity of the dynamic work increases, the heart rate increases, and the rate of oxygen consumption increases; the greater the load on the body, the greater this increase in comparison with the level at rest. Thus, heart rate and oxygen consumption serve as a measure of physical stress.

Ultimately, the adaptation of the body to the action of high physical activity leads to an increase in the power and functional reserves of the cardiovascular system, since it is this system that limits the duration and intensity of the dynamic load.

HYPODYNAMY

Liberation of a person from physical labor leads to physical de-training of the body, in particular, to a change in blood circulation. In such a situation, one would expect an increase in efficiency and a decrease in the intensity of the functions of the cardiovascular system. However, this does not happen - the economy, power and efficiency of blood circulation are reduced.

In the systemic circulation, a decrease in systolic, mean and pulse blood pressure is more often observed. In the pulmonary circulation, when hypokinesia is combined with a decrease in the hydrostatic blood pressure (bed rest, weightless

bridge) increases blood flow to the lungs, increases the pressure in the pulmonary artery.

At rest during hypokinesia:

Heart rate increases naturally;

Cardiac output and BCC decrease;

With prolonged bed rest, the size of the heart, the volume of its cavities, and also the mass of the myocardium noticeably decrease.

The transition from hypokinesia to a mode of normal activity causes:

Pronounced increase in heart rate;

Increase in minute volume of blood flow - IOC;

Decrease in total peripheral resistance.

With the transition to intense muscular work, the functional reserves of the cardiovascular system decrease:

In response to muscle load even low intensity, heart rate rises rapidly;

Shifts in blood circulation are achieved due to the inclusion of less economical components;

At the same time, the IOC grows mainly due to an increase in heart rate.

In conditions of hypokinesia, the phase structure of the cardiac cycle changes:

The phase of blood expulsion and mechanical systole is reduced;

The duration of the phase of tension, isometric contraction and relaxation of the myocardium increases;

The initial rate of increase in intraventricular pressure decreases.

Myocardial hypodynamia. All of the above indicates the development of the phase syndrome of "hypodynamia" of the myocardium. This syndrome, as a rule, is observed in a healthy person against the background of a reduced return of blood to the heart during light exercise.

ECG changes.In hypokinesia, electrocardiogram indices change, which are expressed in positional changes, relative slowing of conduction, decrease in P and T waves, change in the ratio of T values \u200b\u200bin different leads, periodic displacement of the S-T segment, and change in the repolarization process. Hypokinesic changes in the electrocardiogram, regardless of the picture and severity, are always reversible.

Changes in the vascular system. With hypokinesia, a stable adaptation of the vascular system and regional blood flow to these conditions develops (Table 6-3).

Table 6-3.The main indicators of the cardiovascular system in humans under hypokinesia

Changes in the regulation of blood circulation. With hypokinesia, signs of the predominance of sympathetic influences over parasympathetic ones change the system of regulation of heart activity:

The high activity of the hormonal link of the sympathoadrenal system indicates the high stress potential of hypokinesia;

Increased excretion of catecholamines in the urine and their low content in tissues is realized by a violation of hormonal regulation of the activity of cell membranes, in particular, cardiomyocytes.

Thus, the decrease in the functional capabilities of the cardiovascular system during hypokinesia is determined by the duration of the latter and the degree of restriction of mobility.

BLOOD CIRCULATION IN OXYGEN INSUFFICIENCY

With increasing altitude, atmospheric pressure drops and the partial pressure of oxygen (PO 2) decreases in proportion to the decrease in atmospheric pressure. The reaction of the body (primarily of the respiratory, circulatory and blood organs) to oxygen deficiency depends on its severity and duration.

For short-term reactions in high-altitude conditions, only a few hours are required, for initial adaptation - several days or even months, and the stage of stable adaptation of migrants takes years. The most effective adaptive responses are manifested in the indigenous population of high mountainous regions due to long-term natural adaptation.

Initial adaptation period

The movement of a person (migration) from a flat area to the mountains is accompanied by a pronounced change in the hemodynamics of the large and small circle of blood circulation.

Tachycardia develops and the minute volume of blood flow (MCV) increases. Heart rate at an altitude of 6000 m for new arrivals in resting conditions reaches 120 per minute. Physical activity causes more pronounced tachycardia and an increase in IOC than at sea level.

The stroke volume changes insignificantly (both an increase and a decrease can be observed), but the linear blood flow velocity increases.

Systemic blood pressure in the first days of stay at altitudes slightly increases. The rise in systolic blood pressure is mainly caused by an increase in the IOC, and diastolic blood pressure is caused by an increase in peripheral vascular resistance.

BCC increases due to the mobilization of blood from the depot.

Excitation of the sympathetic nervous system is realized not only by tachycardia, but also by paradoxical dilatation of the veins of the systemic circulation, which leads to a decrease in venous pressure at altitudes of 3200 and 3600 m.

There is a redistribution of regional blood flow.

The blood supply to the brain increases due to the reduction of blood flow in the vessels of the skin, skeletal muscles and the digestive tract. The brain is one of the first to react

for oxygen deficiency. This is due to the special sensitivity of the cerebral cortex to hypoxia due to the use of a significant amount of O 2 for metabolic needs (a brain weighing 1400 g consumes about 20% of the oxygen consumed by the body).

In the first days of high-altitude adaptation, blood flow in the myocardium decreases.

The volume of blood in the lungs increases markedly. Primary high-altitude arterial hypertension- an increase in blood pressure in the vessels of the lungs. At the heart of the disease is an increase in the tone of small arteries and arterioles in response to hypoxia, usually pulmonary hypertension begins to develop at an altitude of 1600-2000 m above sea level, its value is directly proportional to the altitude and persists during the entire period of stay in the mountains.

An increase in pulmonary blood pressure during ascent to altitude occurs immediately, reaching its maximum in a day. On the 10th and 30th days, pulmonary blood pressure gradually decreases, but does not reach the initial level.

The physiological role of pulmonary hypertension is to increase the volumetric perfusion of the pulmonary capillaries due to the inclusion of the structural and functional reserves of the respiratory organs in gas exchange.

Inhalation of pure oxygen or a gas mixture enriched with oxygen at high altitude leads to a decrease in blood pressure in the pulmonary circulation.

Pulmonary hypertension in combination with an increase in IOC and central blood volume impose increased demands on the right ventricle of the heart. At high altitudes, when adaptive reactions are disrupted, mountain sickness or acute pulmonary edema can develop.

Altitude thresholds of effects

The effect of oxygen deficiency, depending on the height and the degree of extremeness of the terrain, can be divided into four zones (Fig. 6-3), delimited from each other by effective thresholds (Ruf S., Strughold H., 1957).

Neutral zone. Up to an altitude of 2000 m, the ability for physical and mental activity suffers little or no change.

Full compensation zone. At altitudes between 2000 and 4000 m, even at rest, the heart rate, cardiac output and rate of return increase. The increase in these indicators during operation at such heights occurs at a greater

degree than at sea level, so that both physical and mental performance are significantly reduced.

Incomplete compensation zone (danger zone). At altitudes from 4000 to 7000 m, an unadapted person develops various disorders. Upon reaching the threshold of violations (safety limit) at an altitude of 4000 m, physical performance decreases significantly, as well as the ability to react and make decisions. Muscle twitching occurs, blood pressure decreases, consciousness gradually clouded. These changes are reversible.

Figure: 6-3.Influence of oxygen deficiency during ascent to altitude: the numbers on the left are the partial pressure of O 2 in the alveolar air at the corresponding altitude; the numbers on the right - the oxygen content in gas mixtures, which gives the same effect at sea level

Critical zone. Starting from 7000 m and above, in the alveolar air it becomes below the critical threshold - 30-35 mm Hg. (4.0-4.7 kPa). Potentially lethal disorders of the central nervous system occur, accompanied by unconsciousness and seizures. These disorders can be reversible if the inhaled air increases rapidly. In the critical zone, the duration of oxygen deficiency is critical. If hypoxia continues for too long,

there are violations in the regulatory links of the central nervous system and death occurs.

Long stay in the highlands

With a long stay of a person in high mountain conditions at altitudes up to 5000 m, further adaptive changes in the cardiovascular system occur.

Heart rate, stroke volume and MVV stabilize and decrease to the initial values \u200b\u200band even lower.

Severe hypertrophy of the right heart develops.

The density of blood capillaries in all organs and tissues increases.

BCC remains increased by 25-45% due to an increase in plasma volume and erythrocyte mass. In high altitude conditions, erythropoiesis increases, therefore, the concentration of hemoglobin and the number of erythrocytes increase.

Natural adaptation of the highlanders

The dynamics of the main hemodynamic parameters among the aborigines of the highlands (highlanders) at an altitude of 5000 m remains the same as among the inhabitants of the lowlands at sea level. The main difference between "natural" and "acquired" adaptation to high-altitude hypoxia is the degree of tissue vascularization, microcirculation and tissue respiration. For permanent residents of the highlands, these parameters are more pronounced. Despite the decreased regional blood flow in the brain and heart in the aborigines of the highlands, the minute oxygen consumption by these organs remains the same as in the inhabitants of the plains at sea level.

BLOOD CIRCULATION WITH EXCESS OF OXYGEN

Long-term exposure to hyperoxia leads to the development of toxic effects of oxygen and a decrease in the reliability of adaptive reactions of the cardiovascular system. An excess of oxygen in tissues also leads to increased lipid peroxidation (LPO) and depletion of endogenous antioxidant reserves (in particular, fat-soluble vitamins) and the antioxidant enzymatic system. In this regard, the processes of catabolism and de-energization of cells are enhanced.

The heart rate decreases, the development of arrhythmias is possible.

With short-term hyperoxia (1-3 kgX sec / cm -2), the electrocardiographic characteristics do not go beyond the physiological norm, but after many hours of exposure to hyperoxia, the P wave disappears in some subjects, which indicates the appearance of an atrioventricular rhythm.

Blood flow in the brain, heart, liver and other organs and tissues is reduced by 12-20%. In the lungs, blood flow can decrease, increase and return to its original level.

Systemic blood pressure changes slightly. Diastolic blood pressure usually rises. Cardiac output is significantly reduced and total peripheral resistance is increased. The blood flow rate and BCC during breathing with a hyperoxic mixture are significantly reduced.

The pressure in the right ventricle of the heart and pulmonary artery with hyperoxia often decreases.

Bradycardia with hyperoxia is mainly due to increased vagal effects on the heart, as well as the direct action of oxygen on the myocardium.

The density of the functioning capillaries in the tissues decreases.

The vasoconstriction during hyperoxia is determined either by the direct action of oxygen on smooth muscles vessels, or indirectly - through a change in the concentration of vasoactive substances.

Thus, if the human body responds to acute and chronic hypoxia with a complex and sufficient effective complex adaptive reactions that form the mechanisms of long-term adaptation, the body does not have effective means of protection for the action of acute and chronic hyperoxia.

CIRCULATION AT LOW EXTERNAL TEMPERATURES

There are at least four external factors that have a serious impact on human blood circulation in the Far North:

Sharp seasonal, inter- and intraday changes in atmospheric pressure;

Cold exposure;

A sharp change in photoperiodicity (polar day and polar night);

Fluctuations magnetic field Earth.

The complex of climatic and ecological factors of high latitudes makes strict demands on the cardiovascular system. Adaptation to high latitude conditions is divided into three stages:

Adaptive voltage (up to 3-6 months);

Stabilization of functions (up to 3 years);

Adaptability (up to 3-15 years old).

Primary northern arterial pulmonary hypertension - the most characteristic adaptive reaction. An increase in blood pressure in the pulmonary circulation occurs at sea level under conditions of normal barometric pressure and O 2 content in the air. At the heart of such hypertension is the increased resistance of small arteries and arterioles of the lungs. Northern pulmonary hypertension is widespread among the newcomers and indigenous populations of the circumpolar regions and occurs in adaptive and maladaptive forms.

The adaptive form is asymptomatic, equalizes ventilation-perfusion relations and optimizes the oxygen regime of the body. The systolic pressure in the pulmonary artery in hypertension rises to 40 mm Hg, the total pulmonary resistance increases slightly.

Maladaptive form. Latent respiratory failure - "polar shortness of breath" develops, working capacity decreases. The systolic pressure in the pulmonary artery reaches 65 mm Hg, and the total pulmonary resistance exceeds 200 dyneHsek X cm -5. In this case, the trunk of the pulmonary artery expands, pronounced hypertrophy of the right ventricle of the heart develops, and simultaneously the stroke and minute volumes of the heart decrease.

BLOOD CIRCULATION UNDER EXPOSURE TO HIGH TEMPERATURES

Distinguish between adaptation in arid and humid zones.

Human adaptation in arid zones

Arid zones are characterized by high temperatures and low relative humidity. The temperature conditions in these zones during the hot season and during the daytime are such that the heat input into the body through insolation and contact with hot air can exceed the heat production in the body at rest by 10 times. Similar heat stress in the absence

efficient heat transfer mechanisms quickly leads to overheating of the body.

Thermal states of the body under conditions of high external temperatures are classified as normothermia, compensated hyperthermia and uncompensated hyperthermia.

Hyperthermia- the borderline state of the organism, from which a transition to normothermia or death is possible (heat death). The critical body temperature at which heat death occurs in humans corresponds to + 42-43? C.

The effect of high air temperature on a person who is not adapted to heat causes the following changes.

Expansion of peripheral vessels is the main reaction to heat in arid zones. Expansion of blood vessels, in turn, should be accompanied by an increase in the BCC; if this does not happen, then a drop in systemic blood pressure occurs.

The volume of circulating blood (BCC) increases in the first stages of heat exposure. With hyperthermia (due to evaporative heat transfer), the BCC decreases, which also entails a decrease in central venous pressure.

Total peripheral vascular resistance. In the beginning (first phase), even with a slight increase in body temperature, systolic and diastolic blood pressure decreases. The main reason for the decrease in diastolic pressure is a decrease in the total peripheral vascular resistance. During heat stress, when the body temperature rises to +38 ° C, the total peripheral vascular resistance decreases by 40-55%. This is due to dilatation of peripheral vessels, primarily the skin. A further increase in body temperature (second phase), on the contrary, may be accompanied by an increase in the total peripheral vascular resistance and diastolic pressure with a pronounced decrease in systolic pressure.

Heart rate (HR) increases, especially in less trained and poorly adapted people. In a person at rest at a high external temperature, the increase in the number of heart contractions can reach 50-80%. In well-adapted people, heat does not cause heart rate increases until heat stress becomes too severe.

Central venous pressure increases with an increase in body temperature, but heat exposure can also cause the opposite effect - a transient decrease in central blood volume and a persistent decrease in pressure in the right atrium. The variability of indicators of central venous pressure is due to the difference in the activity of the heart and BCC.

The minute volume of blood circulation (MVC) increases. The stroke volume of the heart remains normal or decreases slightly, which is observed more often. The work of the right and left ventricles of the heart when exposed to high external temperatures (especially with hyperthermia) increases significantly.

A high external temperature, which practically excludes all heat transfer pathways in humans, except for the evaporation of sweat, requires a significant increase in cutaneous blood flow. The increase in blood flow in the skin is provided mainly by an increase in the IOC and, to a lesser extent, by its regional redistribution: under heat load at rest in a person, blood flow in the celiac region, kidneys and skeletal muscles decreases, which "frees" up to 1 L of blood / min; the rest of the increased cutaneous blood flow (up to 6-7 liters of blood / min) is provided by cardiac output.

Intense sweating ultimately leads to dehydration of the body, blood thickening and a decrease in the BCC. This puts additional strain on the heart.

Adaptation of migrants in arid zones. Newly arrived migrants in arid zones of Central Asia, when doing hard physical work, have hyperthermia 3-4 times more often than indigenous people. By the end of the first month of staying in these conditions, the indicators of heat exchange and hemodynamics in migrants improve and approach those of local residents. By the end of the summer season, there is a relative stabilization of the functions of the cardiovascular system. Starting from the second year, the hemodynamic parameters of the migrants hardly differ from those of local residents.

Aboriginal arid zones. The aborigines of the arid zones show seasonal fluctuations in hemodynamic parameters, but to a lesser extent than among migrants. Skin among the indigenous people they are abundantly vascularized, have developed venous plexuses, in which the blood moves 5-20 times slower than in the main veins.

The mucous membrane of the upper respiratory tract also abundantly vascularized.

Human adaptation in humid zones

Human adaptation in humid zones (tropics), where - except elevated temperatures - high relative humidity of air, flows similarly to arid zones. The tropics are characterized by a significant tension in the water and electrolyte balance. For permanent residents of the humid tropics, the difference between the temperature of the "core" and "shell" of the body, hands and feet is greater than that of migrants from Europe, which contributes to better removal of heat from the body. In addition, the aborigines of the humid tropics have more perfect mechanisms for generating heat with sweat than those of visitors. In response to temperatures exceeding + 27 ° C, aboriginal people begin to sweat faster and more intensely than migrants from other climatic and geographical regions. For example, Australian aborigines have twice the amount of sweat evaporated from the surface of the body than Europeans under identical conditions.

CIRCULATION WITH ALTERED GRAVITATION

The gravitational factor has a constant effect on blood circulation, especially in low pressure areas, forming the hydrostatic component of blood pressure. Due to the low pressure in the pulmonary circulation, the blood flow in the lungs largely depends on the hydrostatic pressure, i.e. the gravitational effect of blood.

The model of the gravitational distribution of pulmonary blood flow is shown in Fig. 6-4. In an adult, in an upright position, the tops of the lungs are located about 15 cm above the base of the pulmonary artery, so the hydrostatic pressure in the upper parts of the lungs is approximately equal to the arterial pressure. In this regard, the capillaries of these sections are perfused slightly or not at all. In the lower parts of the lungs, on the contrary, the hydrostatic pressure is added to the arterial pressure, which leads to additional stretching of the vessels and their plethora.

These features of the hemodynamics of the small circle are accompanied by significant unevenness of blood flow in various parts of the lungs. This unevenness significantly depends on the position of the body and is reflected in the indicators of regional saturation.

Figure: 6-4.A model linking the uneven distribution of pulmonary blood flow in an upright position of the human body with the magnitude of the pressure acting on the capillaries: in zone 1 (apex), the alveolar pressure (P A) exceeds the pressure in the arterioles (P a), and the blood flow is limited. In zone 2, where P a\u003e P A, the blood flow is greater than in zone 1. In zone 3, the blood flow is increased and is determined by the difference in pressure in arterioles (P a) and pressure in venules (Py). In the center of the lung diagram - pulmonary capillaries; vertical tubes on the sides of the lung - pressure gauges

blood oxygen. However, despite these features, in a healthy person, the saturation of the blood of the pulmonary veins with oxygen is 96-98%.

With the development of aviation, rocketry, and man's entry into space, changes in systemic hemodynamics under conditions of gravitational overload and weightlessness acquire great importance. Changes in hemodynamics are determined by the type of gravitational loads: longitudinal (positive and negative) and transverse.

QUESTIONS FOR SELF-CONTROL

1. What types of work can be distinguished by heart rate changes?

2. What changes in the myocardium and regional blood circulation are observed during physical exertion?

3. What mechanisms are used to regulate blood circulation during physical exertion?

4. How does oxygen consumption change during exercise?

5. What changes occur in the circulatory system during hypokinesia?

6. Name the types of hypoxia depending on the duration of action.

7. What changes in the circulatory system are observed during adaptation to high mountains?

Description of the presentation by individual slides:

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Leisure branch of MBOU Noskovsk school Presentation Heart work. The influence of environmental factors on the human cardiovascular system. Completed by: Korshunova Nina Vladimirovna Biology teacher

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Formation of new anatomical concepts: phases of the heart, pause, automatic characterize the neurohumoral regulation of this process; to acquaint students with human diseases caused by the influence of environmental factors, with the features of a person's biological and social adaptability to environmental conditions; develop the ability to analyze, generalize, draw conclusions, compare; continue to develop the concept of human dependence on environmental conditions. Lesson Objectives:

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Blood circulation is a closed vascular pathway that provides a continuous blood flow, carries oxygen and nutrition to cells, carries away carbon dioxide and metabolic products. What is blood circulation?

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The heart is located in the pericardium - the pericardium The pericardium secretes fluid that weakens the friction of the heart

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The structure of the blood vessels The structure of the artery Comes from the heart Outer layer - connective tissue Middle layer - thick layer of smooth muscle tissue Inner layer - thin layer epithelial tissue

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The structure of blood vessels The structure of the vein Carries blood to the heart Outer layer - connective tissue Middle layer - thin layer of smooth muscle tissue Inner layer - unilamellar epithelium Have pocket valves

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The human heart is located in the chest cavity. The word "heart" comes from the word "middle". The heart is in the middle between the right and left lungs and is slightly displaced to the left. The apex of the heart is directed downward, forward, and slightly to the left, so heart beats are felt to the left of the sternum. An adult's heart weighs about 300g. The size of a person's heart is approximately equal to the size of his fist. The heart mass is 1/200 of the human body mass. People trained for muscle work have larger hearts.

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The heart contracts approximately 100 thousand times per day, pumping more than 7 thousand liters. blood, according to the expenditure of E, it is tantamount to raising a railway freight car to a height of 1 m. It makes 40 million blows per year. For a person's life, it is reduced 25 billion times. This work is enough to lift the train up the Mont Blanc. Weight - 300 g, which is 1 \\ 200 of body weight, however, 1 \\ 20 of all the body's energy resources are spent on its work. Size - about a clenched fist of the left hand. What is my heart like?

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It is known that the human heart contracts on average 70 times in 1 minute, ejecting about 150 cubic meters with each contraction. see blood. How much blood does your heart pump in 6 lessons? A TASK. DECISION. 70 x 40 \u003d 2800 times reduced in 1 lesson. 2800 x150 \u003d 420.000 cubic meters. cm \u003d 420 l. blood is pumped over in 1 lesson. 420 l. x 6 lessons \u003d 2520 l. blood is pumped over 6 lessons.

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What explains such a high performance of the heart? The pericardium (sac) is a thin and dense shell that forms a closed sac that covers the outside of the heart. Between it and the heart there is a fluid that hydrates the heart and reduces friction during contraction. Coronary (coronary) vessels - vessels feeding the heart itself (10% of the total volume)

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The heart is a four-chambered hollow muscular organ that resembles a flattened cone and consists of 2 parts: right and left. Each part includes an atrium and a ventricle. The heart is located in a connective tissue sac - the pericardial sac. The heart wall consists of 3 layers: Epicardium - the outer layer of connective tissue. The myocardium is a powerful middle muscle layer. The endocardium is the inner layer of squamous epithelium. There is fluid between the heart and the pericardium, which hydrates the heart and reduces friction during its contractions. The muscular walls of the ventricles are much thicker than the walls of the atria. This is because the ventricles do a greater job of pumping blood than the atria. It is particularly thick muscle wall the left ventricle, which, by contracting, pushes blood through the vessels of the systemic circulation.

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The walls of the chambers are composed of cardiac muscle fibers - the myocardium, connective tissue, and numerous blood vessels. Chamber walls vary in thickness. The thickness of the left ventricle is 2.5 - 3 times thicker than the walls of the right. Valves provide movement in exactly one direction. Valvular between atria and ventricles Lunate between ventricles and arteries, consisting of 3 pockets Bivalves on the left Tricusps on the right

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A cardiac cycle is a sequence of events that occur during one heartbeat. Duration less than 0.8 sec. Atria Ventricles Phase II The leaflet valves are closed. Duration - 0.3 s Phase I Flap valves are open. The lunar ones are closed. Duration - 0.1 s. Phase III Diastole, complete relaxation of the heart. Duration - 0.4 s. Systole (contraction) Diastole (relaxation) Systole (contraction) Diastole (relaxation) Diastole (relaxation) Diastole (relaxation) Systole - 0.1 s. Diastole - 0.7 s. Systole - 0.3 s. Distola - 0.5 s.

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The cardiac cycle is a contraction and relaxation of the atria and ventricles of the heart in a certain sequence and strict coordination in time. Phases of the cardiac cycle: 1. Atrial contraction - 0.1 s. 2. Contraction of the ventricles - 0.3 s. 3. Pause (general relaxation of the heart) - 0.4 s. The blood-filled atria contract and push blood into the ventricles. This stage of contraction is called atrial systole. Atrial systoles cause blood to enter the ventricles, which are relaxed at this time. This condition of the ventricles is called diastole. At the same time, the atria are in a state of systole, and the ventricles are in a state of diastole. This is followed by contraction, that is, the systole of the ventricles and blood flows from the left ventricle to the aorta, and from the right to the pulmonary artery. During atrial contraction, the leaflet valves are open, the semilunar valves are closed. During the contraction of the ventricles, the leaflet valves are closed, the semilunar valves are open. Then the return flow of blood fills the "pockets" and the semilunar valves close. When paused, the leaf valves are open and the lunar ones are closed.

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Knowing the cardiac cycle and the time of contraction of the heart in 1 min (70 beats), it can be determined that out of 80 years of life: the muscles of the ventricles rest - 50 years. atrial muscles rest for 70 years.

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A high level of metabolic processes occurring in the heart; The high performance of the heart is due to the increased supply of blood to the heart muscles; The strict rhythm of its activity (the phases of work and rest of each department strictly alternate)

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The heart works automatically; Regulates the central nervous system - the parasympathetic (vagus) nerve - slows down; sympathetic nerve - enhances the work Hormones - adrenaline - enhances, and norepinephrine - slows down; Ions K + slows down the work of the heart; The Ca2 + ion enhances its work. How is the work of the heart regulated?

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The change in the frequency and strength of heart contractions occurs under the influence of impulses of the central nervous system and biologically active substances supplied with the blood. Nervous regulation: in the walls of arteries and veins, numerous nerve endings are laid - receptors that are associated with the central nervous system, due to which, by the mechanism of reflexes, nervous regulation of blood circulation is carried out. The parasympathetic (vagus nerve) and sympathetic nerves go to the heart. Irritation of the parasympathetic nerves reduces the frequency and strength of the heart. In this case, the rate of blood flow in the vessels decreases. Irritation of the sympathetic nerves is accompanied by an acceleration of the heart rate. REGULATION OF HEART RATINGS:

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Humoral regulation - the work of the heart is influenced by various biologically active substances... For example, the hormone adrenaline and calcium salts increase the strength and heart rate, while the substance acetylcholine and potassium ions reduce them. By order of the hypothalamus, the adrenal medulla releases a large amount of adrenaline, a hormone, into the blood wide range Actions: constricts the blood vessels of internal organs and skin, dilates the coronary vessels of the heart, increases the frequency and strength of heart contractions. Adrenaline rush stimuli: stress, emotional excitement. Frequent repetition of these phenomena can cause disruption of the heart.

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For the first time in the world, the experience of reviving an isolated human heart was successfully carried out by the Russian scientist A.A. Kulyabko in 1902 - he revived the heart of a child 20 hours after death, which came from pneumonia. AUTOMATION What is the reason?

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Location: special muscle cells of the right atrium - sinoatrial node Automation is the ability of the heart to rhythmically contract regardless of external influences, but only due to impulses arising in the heart muscle.

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Anthropogenic factors are a combination of the influences of human activity on the environment

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Heart disease (heart disease) is a violation of the normal functioning of the heart. Includes damage to the pericardium, myocardium, endocardium, heart valve apparatus, heart vessels. ICD-10 classification - Sections I00 - I52. HEART DISEASES

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Arrhythmias and conduction disturbances Inflammatory heart disease Valve defects Arterial hypertension Ischemic lesions Damage to the heart vessels Pathological changes CLASSIFICATION OF TYPES OF HEART DISEASES

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Physical exercise can replace many drugs, but no medicine in the world can replace physical exercise J. Tissot. The famous French doctor of the 18th century. Nothing depletes and destroys a person like prolonged inactivity. Aristotle Movement is life!

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Physical education is a generally available way to prevent many diseases and promote health. Physical culture should be an integral part of every person's life.

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To be healthy in full Physical education is necessary for everyone. First, in order - In the morning, let's do some exercises! To develop successfully You need to go in for sports From physical education There will be a slender figure Going in for sports

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On the recommendation of a doctor, you should abandon long and frequent business trips, night and evening shifts, work in the cold; dosed walking is useful, the pulse must be monitored; both unreasonable inactivity and work with overload are harmful, especially in severe disease; the level of permissible loads is determined by the boundaries of the safe heart rate zone, which is individual and determined by the doctor; useful regular morning exercises, complexes of physiotherapy exercises, dosed walking; isometric efforts should be avoided. WORK LOADS

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Annual leave is necessary to strengthen and restore health. It is necessary to agree with the doctor on the choice of the place of rest It is desirable to rest in the climatic zone in which the patient lives. RECREATION AND LEISURE

In conditions modern city a person is exposed to a wide range of environmental social and ecological factors, which largely determine the adverse changes in his health.

Age, sex and individual characteristics of a person determine the boundaries of his functional capabilities, the degree of adaptation of the body to environmental conditions, its physical and social influences, and this is what characterizes the level of his health. From this point of view, the disease is the result of exhaustion and breakdown of adaptive mechanisms, when the resistance to adverse influences is sharply reduced. The functional capabilities of the organism, which determine the degree of realization of vital biological and social needs, constitute the so-called adaptive potential.

Environmental pollution affects the physical and mental health of a person, his vitality, labor productivity.

The adaptive adaptive capabilities of a person are not always sufficient for the normal functioning of the body in a new ecological environment, which leads to serious consequences. The response of the human body to the influence of new negative environmental factors should be considered the emergence of previously unknown medical diseases, as well as an increase in the prevalence and severity of many forms of pathology. This is especially evident in living conditions in large cities with developed industry. Fixed here:

chemical pollution of air, water, land, food;

acoustic discomfort;

artificial use of substandard building materials and other disadvantages of urban planning;

harmful energy radiation;

geopathogenic zones, etc.

According to V.V. Khudolei, S.V. Zubarev and O.T. Dyatlechenko, the main changes in all health indicators characteristic of the modern period of development of our country include:

acceleration of the rate of changes in all health indicators;

the formation of a new, non-epidemic type of pathology;

acceleration of demographic changes, expressed in an aging population;

an increase in the incidence of diseases of the circulatory system, chronic nonspecific diseases of the respiratory system;

a sharp increase in the proportion of endocrine, allergic, congenital malformations, diseases of the immune system, as well as some infectious diseases;

the formation of multiple pathology.

A significant part of the population is now in a state where the disease has not yet manifested itself, but general malaise is becoming a common background condition. The most severe health effects of urban dwellers are chronic degenerative changes external environment of cities. Chemical substances circulating in the environment enter the human body in relatively small quantities, therefore, with a low intensity of their impact, as a rule, there is no rapid onset of clearly expressed pathological changes. Morbidity and even more mortality in such cases is the last stage the process of intoxication of the body with harmful substances.

The relationship between the level of human exposure to limiting factors and the state of health (in particular, the level of morbidity) is nonlinear. So, for example, at a low level of chemical pollution of the environment, activation of the body's protective reserves is observed - stimulation of neutralization. These processes occurring in the human body are weakly manifested in morbidity indicators. An increase in the level of chemical exposure is accompanied by inhibition of the processes of excretion from the body and neutralization of xenobiotics. A further increase in the level of environmental pollution leads to a sharp increase in the number of cases of pathologies in the population. As the exposure to pollutants increases, adaptation mechanisms are activated that stabilize the incidence rate. Further, there is a breakdown of adaptation mechanisms, which leads to another rise in the incidence rate of the population (Fig. 1). It should be borne in mind that the presented diagram of the dependence of morbidity on the ecological state of the environment is very simplified, since the causal factors of human disease are extremely numerous and affect a person in various combinations with each other.

Figure: 1. Simplified diagram of the dynamics of population morbidity (solid line) with an increase in the dose load of pollutants (dotted line) (after: Kiselev, Fridman, 1997)

The pathological process is a complete manifestation of the impact of adverse environmental factors on the human body and its functions. Signs of a pathological process in the body, along with the presence of an acute or chronic disease, are also changes in physiological functions (for example, pulmonary ventilation, functions of the central nervous system, blood oxidation), subjective symptomatology of various types, and changes in internal comfort. Therefore, the chronic impact of environmental pollutants on the health of the population at first manifests itself in the form of functional disorders, changes in immunobiological reactivity, slowing down of physical development, but in the future it can lead to severe long-term consequences, including genetic ones. Environmental pollution is not only an etiological factor in the appearance of certain pathological conditions of the body, it has a known provoking role in the occurrence of chronic nonspecific diseases, its influence aggravates the course and prognosis of these pathological conditions of the body.

It is believed that the morbidity of the population in large cities up to 40% (and in areas near powerful emission sources - up to 60%) is associated with environmental pollution, while in small cities it is no more than 10%. From the point of view of the health of city dwellers, the leading role is played by atmospheric air pollution, since through it a person's contacts with the environment are more intense and lasting than through water and food. In addition, many chemicals affect the body more actively if they enter it through the respiratory system. Atmospheric precipitation, absorbing gaseous, liquid and solid components of polluted air, acquires a new chemical composition and physicochemical properties.

Most of the studies are devoted to the study of the impact on the health of the urban population of individual components of the environment. Atmospheric pollution has been studied most fully. A statistically significant dependence of the incidence of the population on air pollution was established for bronchitis, pneumonia, pulmonary emphysema (expansion of the pulmonary vesicles - alveoli, leading to compression of small blood vessels and deterioration of gas exchange processes), acute respiratory diseases. The reliable influence of air pollution on the duration of diseases has been established.

The danger of air pollution for the human body is largely determined by the fact that even with low concentrations of pollutants, due to round-the-clock filtration of polluted air by the lungs, a significant amount of harmful substances can enter the body. In addition, in the lungs there is a direct contact of pollutants with blood, which then enters the systemic circulation, bypassing the important detoxification barrier - the liver. That is why the poisons that enter the human body in the process of breathing often act 80 to 100 times stronger than in the case of their ingestion through the gastrointestinal tract. The degree of influence of the polluted atmosphere on the human body depends on the age of the people. The most sensitive are 3-6 year old children and the elderly over 60 years old.

Nitrogen oxides are a typical pollutant for the urban environment. They are formed during the combustion of any type of fuel, and in cities the share of motor transport accounts for up to 75% of their total emissions. It is important to emphasize that even if there is no nitrogen in the fuel, nitrogen oxides are still formed due to the interaction of oxygen and atmospheric nitrogen during its combustion. When a person inhales air containing nitrogen oxides, they interact with the moist surface of the respiratory system and form nitric and nitrous acids that affect the alveolar tissue of the lungs. This leads to their swelling and reflex disorders. In the respiratory tract, they combine with tissue alkalis and form nitrates and nitrites. Disruption of the respiratory system gradually but steadily leads to an increase in the load on the heart and blood vessels, which, ultimately, can be fatal. This circumstance explains the clearly expressed tendency rapid growth deaths among patients with the indicated nosological forms of diseases during the period of a sharp rise in the concentration of toxic substances in the air. Many other atmospheric pollutants can also adversely affect the cardiovascular system. In particular, carbon monoxide causes tissue hypoxia, which, in turn, contributes to the occurrence of negative changes in the cardiovascular system.

Formed as a result of inhalation of air containing nitric oxide, nitrites and nitrates adversely affect the activity of almost all enzymes, hormones and other proteins that regulate metabolism, growth, development, reproduction of the body. At a concentration of nitrogen dioxide less than 205 μg / m 3, changes are observed at the cellular level in humans. At a concentration of 205 to 512 μg / m 3, adaptive mechanisms are disrupted sensory systems, and at concentrations from 512 to 1025 μg / m 3, changes occur in biochemical processes and the structural organization of the lungs. Nitrogen dioxide concentrations in the range of 1025-3075 μg / m 3 cause an increase in airway resistance in patients with bronchial diseases, and in the range of 3075-5125 μg / m 3 - the same changes, but in healthy people.

Sulfur dioxide irritates the respiratory tract, leads to bronchial spasms, as a result of its interaction with the mucous membrane, sulfurous and sulfuric acids are formed. The general effect of sulfur dioxide is manifested in the violation of carbohydrate and protein metabolism, inhibition of oxidative processes in the brain, liver, spleen, muscles. It irritates the hematopoietic organs, promotes the formation of methemoglobin, causes changes in the endocrine organs, bone tissue, violates the generative function of the body, embryotoxic and gonadotoxic actions.

Serious problems for the urban population arise when the concentration of ozone in the surface layer of air increases. It is a very powerful oxidizing agent, and its toxicity increases with increasing air temperature. Patients with asthma and allergic rhinitis (rhinitis) are more sensitive to ozone.

The role of products of combustion of automobile fuel as environmental pollutants is great. In the exhaust gases of cars is, and in significant quantities, carbon monoxide - carbon monoxide. Carbon monoxide, binding in the blood and hemoglobin of erythrocytes, turns into carboxyhemoglobin, which, unlike hemoglobin, does not have the ability to carry oxygen to the tissues of the body.

Thus, tissue respiration worsens, having a negative effect on the activity of the cardiovascular system, functional state central nervous system. Therefore, people who are in areas of high gas concentrations often have signs of chronic carbon monoxide poisoning: fatigue, headaches, tinnitus, pain in the heart.

Polynuclear aromatic hydrocarbons, substances with toxic properties, are widespread in the air environment surrounding townspeople. The impact of these substances on the human body is often associated with the appearance of malignant neoplasms. This group includes benzo (a) pyrene, which is characterized by the most pronounced mutagenic and carcinogenic activity, although, according to experts from the International Agency for Research on Cancer, there is no direct evidence of its carcinogenicity in relation to humans. This group of substances includes dioxins. The main sources of their emissions are cars running on gasoline with anti-carbon additives, waste incinerators and even conventional stoves. The sources of dioxins are steel mills and pulp and paper mills, traces of dioxins are found in products formed with the participation of chlorine. They are transported over long distances in the atmosphere (mainly sorbed on particulate matter) and therefore spread globally. Many organochlorine compounds (including dioxins) are believed to reduce the efficiency of the immune system. As a result, the likelihood of viral diseases increases and the severity of their course increases, the processes of tissue regeneration (healing) slow down, which is decisive in the aging of self-renewing tissues.

In general, we can say that various chemicals that pollute the atmosphere of cities are characterized by some uniformity of action on the human body. So, many of them irritate the mucous membranes, which leads to an increase in the number inflammatory diseases respiratory organs, ENT organs, eyes. Even in small quantities, they weaken the protective properties of the human body, affecting its immunological reactivity, increasing the incidence of the cardiovascular system and bronchial asthma. A positive relationship was found between the level of air pollution in cities and the growth of diseases of a genetic nature, an increase in the number of malignant neoplasms, an increase in allergic diseases, and an increase in metabolic disorders. On the basis of studies carried out in the Japanese city of Osako, the relationship between the level of air pollution and the death rate of city residents is shown.

This connection with cardiovascular, respiratory diseases, and chronic rheumatic heart diseases is especially pronounced.

A specific problem for the population of many cities is the consequences of the chlorination of drinking water. During its chlorination, the transformation of organochlorine and organophosphorus pesticides into substances that turn out to be 2 times more toxic than the original components is observed. Chemical pollution of drinking water primarily causes diseases of the digestive system and excretory system. These include gastritis, stomach ulcers, cholelithiasis and urolithiasis, nephritis. So, with an increase of 3-5 times in the content of chlorides and sulfates in water, the incidence of the population of bile and urolithiasis, while there is an increase in vascular pathology. Water pollution with organic and inorganic industrial wastes leads to damage to the liver, hematopoietic apparatus, and the deposition of calcium salts.

The problem of the impact of water pollution on human health is becoming increasingly important in connection with the fundamental changes in the very nature of wastewater. Both industrial and domestic wastewater contain waste of synthetic detergents, which are based on surfactants - detergents. Treatment facilities used at modern waterworks do not provide the required efficiency of water purification from surfactants, which is the reason for their appearance in drinking water. When detergents enter the gastrointestinal tract, the walls of the esophagus and stomach are damaged, thereby impairing their permeability. Having a long-term chronic effect on the human body, these substances can cause a sharp deterioration in the course of many diseases of internal organs.

The problem of water pollution and its consequences for the human body is closely related to the sanitary and hygienic state of the soil. At present, in agriculture, mineral fertilizers and chemical plant protection agents - pesticides are used in huge quantities. Organochlorine compounds belonging to the pesticide group, such as DDT and hexochlorane, are relatively stable in the external environment and are able to accumulate in the tissues and fat of animal organisms. High concentrations of DDT and its metabolites, affecting mainly the parenchymal organs and the central nervous system, contribute to the development of cirrhosis, malignant tumors, hypertension.

Among the environmental factors that adversely affect the health of the urban population, in addition to chemical and biological substances, one should also include physical pollutants: noise, vibration, electromagnetic vibrations, and radioactive radiation.

Acoustic noise is one of the most important physical types of environmental pollution. Studies have established that in terms of the degree of harmfulness of exposure to noise, it ranks second after chemical pollution of the environment. Daily exposure to weak noise worsens health, reduces alertness, contributes to neuroses, nervous system disorders and loss of hearing acuity. Under the action of noise, there are shifts in metabolism in the nervous tissue, the development of hypoxia, neurohumoral shifts in the body. Noise can cause activation of the organ system internal secretion in the form of an increase in the content of activating hormones in the blood and an increase in metabolic processes, inhibition of natural immunity, which can contribute to the formation of pathological processes.

According to Australian researchers, noise in cities leads to a reduction in life by 8-12 years. It is believed that when the level of street noise rises to 50-60 dB SL, the number of cardiovascular diseases in the population increases. City noise causes ischemic heart disease, hypertension. People living in a noisy area have higher blood cholesterol levels more often than people living in quiet neighborhoods. The totality of all disorders and dysfunctions arising under the influence of industrial noise received, at the suggestion of E.Ts. Andreeva-Galanina and co-authors the general name "noise sickness".

Many problems arise in connection with the impact of man-made magnetic and electromagnetic fields on a person. They have a negative effect on the nervous system, and the cardiovascular and endocrine systems play the most significant role in the responses to this powerful anthropogenic factor. Yu.A. Dumansky et al (1975) found the effect of short waves on the cardiovascular system, characterized by a decrease in pulse rate, vascular hypotension, and impaired cardiac conduction.

Conducted in the late 1980s. studies by American epidemiologists have revealed a positive relationship between the level of technogenic electromagnetic fields and the growth of a number of diseases in the population: leukemia, brain tumors, multiple sclerosis, and oncological diseases. The nervous system is most sensitive to the effects of fields. The immune system is also significantly suppressed, and therefore the course of the infectious process in the body is aggravated, the immune system begins to act against the normal tissue antigens of its own body.

Summarizing the analysis of the literature on the pathophysiological features of the impact on the body of various anthropogenic environmental factors, we can conclude that, on the one hand, each of them can selectively affect the functions of individual organs and systems of the body and, thus, have a specific effect. On the other hand, these factors also have a nonspecific effect, affecting, first of all, the central and autonomic nervous system, in connection with which unfavorable shifts in various organs and systems can be observed.

As can be seen from the material presented above, many physical and chemical features of the environment are among the factors affecting the health of the population of urbanized areas. However, this list is incomplete if social conditions are not included. Of the latter, the most important are the saturation of contacts and information redundancy of the environment. The rapid development of mass communications, according to many researchers, has caused ecopsychological stress. Overloading the psyche with a huge stream of contradictions, as a rule, negative information led to the development, in particular, of information stresses. Long-term stresses cause a violation of the immune and genetic apparatus, become the cause of many mental and somatic diseases, and increased mortality.

The appearance of pathologies in certain organs and systems under the influence of negative anthropogenic environmental factors can become a direct cause of premature aging of the human body, and even death.

The general mortality rate of the population and the average life expectancy are in international practice the most important indicators reflecting public health. The last 15 years in Russia there has been a deterioration in almost all demographic indicators. The dynamics of average life expectancy and mortality in our country is very unfavorable. Today, the average life expectancy in Russia is less than in developed countries, where the 70-year mark has long been crossed. In our country, this figure is 67.7 years.

In order to determine which factors determine life expectancy, one should get acquainted with the structure of morbidity and mortality in the population. The incidence of the population of Russia is mainly determined by five classes of diseases. They account for more than 2/3 of all diseases. The most common diseases of the respiratory system - more than 1/3 of all diseases. The second place is occupied by diseases of the nervous system and sense organs. This is followed by diseases of the cardiovascular system, diseases of the digestive system, as well as accidents, injuries and poisoning. The number of viral diseases is also growing.

The structure of mortality in Russia has certain differences from other countries of the world. Both in developed countries and in Russia, most people die from cardiovascular diseases (currently, this is the cause of death for almost 56% of Russians). It should be noted that in our country mortality from this cause has doubled in recent years and acquired the character of an epidemic. In second place among the causes of death are accidents, injuries and poisoning, suicide and homicide. For example, more than 30 thousand people die on the roads every year, and about 60 thousand people die from suicides. Further among the causes of death are oncological diseases and respiratory diseases.

Environmental quality combined with lifestyle causes disease in 77% of cases and premature death in 55%. However, in real life, a small percentage of the population is exposed to these extreme manifestations (illness and death). In the bulk of the population living in conditions of varying degrees of environmental pollution, the so-called pre-biological conditions are formed: physiological, biochemical and other changes in the body, or there is an accumulation of certain pollutants in organs and tissues without visible signs of health impairment. This "pollution" of the body over time, along with a decrease in the number of any non-renewing structures and a deterioration in the quality of regulation and coordination of vital processes in the body, is one of the main causes of aging of the body, including premature. Premature aging is defined as any partial or more general acceleration in the rate of aging that results in a person being ahead of the average aging level of their age group.

In socio-economic and medical terms, premature aging, combined with age-related diseases that develop rapidly, lead to senility and disability, is of the greatest importance. The decline in labor resources is directly dependent on the decline in the life potential of the population. Thus, the most essential need of modern society is the development of new medical preventive and therapeutic and health-improving technologies aimed at significantly increasing the health potential and slowing down the aging process itself.

2.2.5. Influence of environmental factors on the prevalence of some diseases

A large number of scientific studies have been devoted to the study of the relationship between environmental factors and various types of diseases, a huge number of articles and monographs have been published. We will try to give a very short analysis of only the main lines of research on this problem.

When analyzing causal relationships between health indicators and the state of the environment, researchers, first of all, pay attention to the dependences of health indicators on the state of individual components of the environment: air, water, soil, food, etc. 2.13 provides an indicative list of environmental factors and their influence on the development of various pathologies.

As you can see, air pollution is considered one of the main causes of diseases of the circulatory system, congenital anomalies and pathologies of pregnancy, neoplasms of the mouth, nasopharynx, upper respiratory tract, trachea, bronchi, lungs and other respiratory organs, neoplasms of the genitourinary system.

Among the causes of these diseases, air pollution is in the first place. Air pollution ranks second, third and fourth among the causes of other diseases.

Table 2.13

An indicative list of environmental factors in connection with their

possible impact on prevalence

some classes and groups of diseases

	Pathology
	Diseases of the circulatory system	1. Air pollution with sulfur oxides, carbon monoxide, nitrogen oxides, phenol, benzene, ammonia, sulfur compounds, hydrogen sulfide, ethylene, propylene, butylene, fatty acids, mercury, etc. 3. Housing conditions 4. Electromagnetic fields 5. Composition of drinking water: nitrates, chlorides, nitrites, water hardness 6. Biogeochemical features of the area: lack or excess of calcium, magnesium, vanadium, cadmium, zinc, lithium, chromium, manganese, cobalt, barium, copper, strontium, iron in the environment 7. Environmental pollution with pesticides and toxic chemicals 8. Natural and climatic conditions: speed of weather change, humidity, barometric pressure, insolation level, wind strength and direction
	Diseases of the skin and subcutaneous tissue	1. Insolation level 3. Air pollution
	Diseases of the nervous system and sense organs. Mental disorders	1. Natural and climatic conditions: the speed of weather change, humidity, barometric pressure, temperature factor 2. Biogeochemical features: high mineralization of soil and water 3. Housing conditions 4. Air pollution with sulfur oxides, carbon monoxide, nitrogen oxides, chromium, hydrogen sulfide, silicon dioxide, formaldehyde, mercury, etc. 6. Electromagnetic fields 7. Organochlorine, organophosphate and other pesticides
	Respiratory diseases	1. Natural and climatic conditions: the speed of weather changes, humidity 2. Housing conditions 3. Air pollution: dust, sulfur oxides, nitrogen oxides, carbon monoxide, sulfur dioxide, phenol, ammonia, hydrocarbon, silicon dioxide, chlorine, acrolein, photooxidants, mercury, etc. 4. Organochlorine, organophosphate and other pesticides
	Diseases of the digestive system	1. Pollution of the environment with pesticides and toxic chemicals 2. Lack or excess of trace elements in the external environment 3. Housing conditions 4. Air pollution by carbon disulfide, hydrogen sulfide, dust, nitrogen oxides, chlorine, phenol, silicon dioxide, fluorine, etc. 6. Composition of drinking water, water hardness

Continuation of table. 2.13

	Diseases of the blood and blood-forming organs	1. Biogeochemical features: lack or excess of chromium, cobalt, rare earth metals in the environment 2. Air pollution with sulfur oxides, carbon monoxide, nitrogen oxides, hydrocarbons, hydrazoic acid, ethylene, propylene, amylene, hydrogen sulfide, etc. 3. Electromagnetic fields 4. Nitrite and nitrate in drinking water 5. Environmental pollution with pesticides and toxic chemicals.
	Congenital anomalies	4. Electromagnetic fields
	Diseases endocrine system, eating disorders, metabolic disorders	1. Insolation level 2. Excess or deficiency of lead, iodine, boron, calcium, vanadium, bromine, chromium, manganese, cobalt, zinc, lithium, copper, barium, strontium, iron, urochrome, molybdenum in the external environment 3. Air pollution 5. Electromagnetic fields 6. Hardness of drinking water
	Diseases of the genitourinary organs	1. Lack or excess of zinc, lead, iodine, calcium, manganese, cobalt, copper, iron in the environment 2. Air pollution with carbon disulfide, carbon dioxide, hydrocarbon, hydrogen sulfide, ethylene, sulfur oxide, butylene, amylene, carbon monoxide 3. Hardness of drinking water
	Including: pathology of pregnancy	1. Air pollution 2. Electromagnetic fields 3. Environmental pollution with pesticides and toxic chemicals 4. Lack or excess of trace elements in the external environment
	Neoplasms of the mouth, nasopharynx, upper respiratory tract, trachea, bronchi, lungs and other respiratory organs	1. Air pollution 2. Humidity, insolation level, temperature factor, number of days with dry winds and dust storms, barometric pressure

Continuation of table. 2.13

Neoplasms of the esophagus, stomach and other digestive organs

1. Environmental pollution with pesticides and pesticides

2. Air pollution with carcinogenic substances, acrolein and other photooxidants (nitrogen oxides, ozone, surfactants, formaldehyde, free radicals, organic peroxides, fine aerosols).

3. Biogeochemical features of the area: lack or excess of magnesium, manganese, cobalt, zinc, rare earth metals, copper, high soil mineralization

4. Composition of drinking water: chlorides, sulfates. Hardness of water

Neoplasms of the genitourinary organs

1. Air pollution by carbon disulfide, carbon dioxide, hydrocarbon, hydrogen sulfide, ethylene, butylene, amylene, sulfur oxides, carbon monoxide

2. Environmental pollution with pesticides

3. Lack or excess of magnesium, manganese, zinc, cobalt, molybdenum, copper in the environment

4. Chlorides in drinking water

The second in the degree of influence on the incidence due to environmental reasons in most cases can be considered a lack or excess of trace elements in the external environment. For neoplasms of the esophagus, stomach and other digestive organs, this is manifested in the biogeochemical features of the area: lack or excess of magnesium, manganese, cobalt, zinc, rare earth metals, copper, high soil mineralization. For diseases of the endocrine system, eating disorders, metabolic disorders - this is an excess or lack of lead, iodine, boron, calcium, vanadium, bromine, chromium, manganese, cobalt, zinc, lithium, copper, barium, strontium, iron, urochrome, molybdenum in external environment, etc.

Table data 2.13 show that cancer-causing chemicals, dust, and mineral fibers tend to act selectively to target specific organs. Most cancers in action chemical substances, dust and mineral fibers are obviously associated with professional activities. However, as shown by risk studies, the population living in areas affected by hazardous chemical industries (for example, in the city of Chapayevsk) is also exposed. In these zones, elevated levels cancer diseases. Arsenic and its compounds, as well as dioxins, affect the entire population due to its high prevalence. Household habits and food products naturally affect the entire population.

The work of many Russian and foreign scientists is devoted to the study of the possibility of the intake of toxic substances simultaneously in several ways and their complex impact on the health of the population (Avaliani S.L., 1995; Vinokur I.L., Gildenskiold R.S., Ershova T.N., etc. ., 1996; Gildenskiold R.S., Korolev A.A., Suvorov G.A. et al., 1996; Kasyanenko A.A., Zhuravleva E.A., Platonov A.G. et al., 2001; Ott WR, 1985).

One of the most dangerous chemical compounds are persistent organic pollutants (POPs), which enter the environment during the production of chlorine-containing substances, incineration of household and medical waste, and the use of pesticides. These substances include eight pesticides (DDT, aldrin, dieldrin, endrin, heptachlor, chlordane, toxaphene, mirex), polychlorinated biphenyls (PCBs) dioxins, furans, hexachlorobenzene (Revich BA, 2001). These substances pose a danger to human health, regardless of the ways in which they enter the body. Table 2.14 shows the exposure characteristics of the listed eight pesticides and polychlorinated biphenyls.

As you can see, these substances also affect reproductive functions, and are the cause of cancer, lead to disorders of the nervous and immune systems and other equally dangerous effects.

Table 2.14

Health effects of POPs (short list): empirical findings

(Revich B.A., 2001)

Substances	Impact
	Reproductive damage in wildlife, especially egg shell thinning in birds
	DDE, a metabolite of DCT, may be associated with breast cancer (M.S, Wolff, P.G. Toniolo, 1995), but the results are ambiguous (N. Krieger et al., 1994; D.J. Hunter et al., 1997)
	High doses lead to disorders of the nervous system (convulsions, tremors, muscle weakness) (R. Carson, 1962)
Aldrin, Deel Drin, Endrin	These substances have a similar pattern of action, but endrin is the most toxic of them.
	Associated with suppression of the immune system (T. Colborn, C. Clement, 1992)
	Nervous system disorders (convulsions), effects on liver function at high exposure levels (R. Carson, 1962)
Aldrin, Deel Drin, Endrin	Dieldrin - effects on reproductive function and behavior (S. Wiktelius, C.A. Edwards, 1997)
	Possible human carcinogen; in high concentrations, probably contributes to the emergence of breast tumors (K. Nomata et al., 1996)
Heptachlor	Effects on progesterone and estrogen levels in laboratory rats (J.A. Oduma et al., 1995)
Heptachlor	Disturbances of the nervous system and liver function (EPA, 1990)
Hexachlorobene- ash (HCB)
	Affects DNA in human liver cells (R. Canonero et al., 1997)
	Changes in the function of white blood cells during production exposure (M.L. Queirox et al., 1997)
	Changes in steroid formation (W.G. Foster et al., 1995)
	High exposure levels have been associated with porphyrinuria. metabolic liver disease (I.M. Rietjens et al., 1997)
	Thyroid enlargement, scarring and arthritis occur in the offspring of accidentally exposed women (T. Colborn, C. Clement, 1992)
	Probable human carcinogen
	Causes suppression of the immune system (T. Colborn, C. Clement, 1992)
	In rats, it exhibits toxic effects on the fetus, including the formation of cataracts (WHO, Environmental Health Criteria 44: Mirex, 1984)
	Liver hypertrophy due to long-term low dose exposure in rats (WHO, 1984)

Continuation of table 2.14

Polychlorinated dibenzo p- dioxins - PCDDs and polychlorinated dibenzofurans - PCDF	Toxic effects on development, endocrine, immune system; human reproductive function
	2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDC) is a human carcinogen (IARC, 1997)
	Developmental and immune system toxicity in animals, especially rodents (A. Schecter, 1994)
	Changes in hormone levels - estrogen, progesterone, testosterone and thyroid - in some individuals; decrease in serum testosterone levels in exposed people (A. Schecter, 1994)
	Interferes with the action of estrogen in some individuals; decrease in fertility, brood size and uterine weight in mice, rats, primates (A. Schecter, 1994)
	Chloracne as a response to a high dose due to cutaneous or systemic exposure (A. Schecter, 1994)
	Acneform rash due to skin contact (N.A. Tilson et al., 1990)
	Estrogenic effects on wildlife (J.M. Bergeron et al., 1994)
Toxaphene	Potentially human carcinogen, causing reproductive and developmental disorders in mammals
Toxaphene	Shows estrogenic activity (S.F. Arnold et al., 1997)
Polychlorinated biphenyls - PCBs	Impact on the fetus, which results in changes in the nervous system and development of the child, a decrease in his psychomotor functions, short-term memory and cognitive functions, long-term effects on intelligence (N.A. Tilson et al. 1990; Jacobson et al., 1990; JL Jacobson, SW Jacobson, 1996)

In the XX century, for the first time, environmental diseases arose, that is, diseases, the occurrence of which is associated only with the effect of specific chemicals (Table 2.15). Among them, the best known and well-studied diseases associated with exposure to mercury are Minamata disease; cadmium - Itai-Itai disease; arsenic - "black foot"; polychlorinated biphenyls - Yu-Sho and Yu-Cheng (Revich B.A., 2001).

Table 2.15

Pollutants and Environmental Diseases of the Population

Contaminants	Environmental diseases
Arsenic in food and water	Skin cancer - the province of Cordoba (Argentina), "black foot" - the island of Taiwan. Chile
Methylmercury in water, fish	Minamata disease. 1956, Niigata, 1968 -Japan
Methylmercury in food	Deaths - 495 people, poisoning - 6,500 people - Iraq, 1961
Cadmium in water and rice	Itai-Itai Disease - Japan, 1946
Rice contamination with PCB oil	Yu-Sho disease - Japan, 1968; Yu-Cheng disease - Taiwan Island, 1978-1979

When studying cancers of the population associated with exposure to various chemicals, it is useful to know which substances are recognized as responsible for the disease of certain organs (Table 2.16).

Table 2.16

Proven human carcinogens (IARC group 1)

(V. Khudoley, 1999;Revich B.A., 2001)

	Factor name		Target Organs		Population group
1. Chemical compounds
	4-Aminobiphenyl		Bladder
	Benzidine		Bladder
			Hematopoietic system
	Beryllium and its compounds
	Bis (chloromethyl) ether and technical chloromethyl ether
	Vinyl chloride		Liver, blood vessels (brain, lungs, lymphatic system)
	Mustard gas (sulfur mustard gas)		Pharynx, larynx, lungs
	Cadmium and its compounds		Lungs, prostate gland
	Coal pitches		Skin, lungs, bladder (larynx, oral cavity)
	Coal tar		Skin, lungs (bladder)
	Mineral oils (unrefined)		Skin (lungs, bladder)
	Arsenic and its compounds		Lungs, skin		General population groups
	2-Naphthylamine		Bladder (lungs)
	Nickel and its compounds		Nasal cavity, lungs
	Shale oils		Skin (gastrointestinal tract)
	Dioxins		Lungs (subcutaneous tissue, lymphatic system)		Workers, general population groups
	Chromium hexavalent		Lungs (nasal cavity)
	Ethylene oxide		Hematopoietic and lymphatic systems
2. Household habits
		Alcoholic drinks		Pharynx, esophagus, liver, larynx, oral cavity (mammary gland)		General population groups
		Chewing betel nut with tobacco		Oral cavity, pharynx, esophagus		General population groups
		Tobacco (smoking, tobacco smoke)		Lungs, bladder, esophagus, larynx, pancreas		General population groups
		Tobacco products, smokeless		Oral cavity, pharynx, esophagus		General population groups
3. Dust and mineral fibers
			Lungs, pleura, peritoneum (gastrointestinal tract, larynx)
	Wood dust		Nasal cavity and paranasal sinuses
	Crystalline silicon
			Skin, lungs

			Pleura, peritoneum

Continuation of table 2.16

A number of pollutants and ionizing radiation have a negative impact on reproductive health - see table. 2.17 - (Revich B.A., 2001).

Table 2.17

Contaminants and Reproductive Health Disorders

(Priority Health Conditions, 1993;T... Aldrich, J. Griffith, 1993)

Substance	Violations
Ionizing radiation	Infertility, microcephaly, chromosomal abnormalities, cancer in children
	Menstrual irregularities, spontaneous abortion, blindness, deafness, mental retardation
	Infertility, spontaneous abortion, congenital malformations, low birth weight, sperm disorders
	Low birth weight
Manganese	Infertility
	Spontaneous abortions, weight loss in newborns, congenital malformations
Polyaromatic hydrocarbons (PAHs)	Decreased fertility
Dibromochloropropane	Infertility, sperm changes
	Spontaneous abortion, low birth weight, congenital malformations, infertility
1,2-dibromo-3-chloro-propane	Semen disorders, sterility
	Congenital defects developmental (eyes, ears, mouth), central nervous system disorders, perinatal mortality

Dichlorethylene	Congenital malformations (heart)
Dieldrin	Spontaneous abortion, premature birth
Hexachlorocyclohexane	Hormonal disorders, spontaneous abortion, premature birth
	Spontaneous abortion, low birth weight, menstrual irregularities, ovarian atrophy
Carbon disulfide	Menstrual irregularities, spermatogenesis disorders
Organic solvents	Congenital malformations, cancer in children
Anesthetics	Infertility, spontaneous abortion, low birth weight, tumors in the embryo

Since 1995, Russia has begun to implement a methodology for assessing the health risks of the population caused by environmental pollution, developed by the United States Environmental Protection Agency (USA EPA). In a number of cities (Perm, Volgograd, Voronezh, Novgorod Veliky, Volgograd, Novokuznetsk, Krasnouralsk, Angarsk, Nizhniy Tagil), projects to assess and manage the public health risk caused by pollution were carried out with the support of the Agency for International Development and the US Environmental Protection Agency. air and drinking water (Risk Management, 1999; Risk Methodology, 1997). Much credit for carrying out these studies, organizing work and introducing scientific results belongs to the outstanding Russian scientists G.G. Onishchenko, S.L. Avaliani, K.A. Bushtueva, Yu.A. Rachmanin, S.M. Novikov, A.V. Kiselev and others.

Test questions and tasks

1. Analyze and characterize the environmental factors at various diseases (see table 2.13).

2. What diseases are caused by exposure to persistent organic pollutants?

3. List the most famous diseases that appeared in the twentieth century, the impact of which substances were they caused and in what way?

4. What substances are classified as proven carcinogens and diseases of which human organs do they cause?

5. What substances cause reproductive health problems?

6. Analyze and characterize the influence of environmental factors on various types of pathologies in accordance with table 2.14.

Influence of environmental factors on the circulatory system. Presentation on "the influence of factors on the cardiovascular system"

2.2.5. Influence of environmental factors on the prevalence of some diseases

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