To a large extent characterize the nature and pace of human aging. As a person ages, significant changes in the cardiovascular system occur.

Elastic arteries (aorta, coronary, renal, cerebral arteries) and the arterial wall change significantly due to compaction of the inner lining, deposition of calcium salts and lipids in the middle lining, atrophy of the muscle layer, and decreased elasticity.

This leads to thickening of the arterial walls and a constant increase in peripheral vascular resistance, an increase in systolic blood pressure, and an increase in the load on the ventricular myocardium; the blood supply to the organs becomes less than adequate.

In old age and senility, a number of hemodynamic features are formed: systolic blood pressure increases mainly arterial pressure), venous pressure, cardiac output, and later cardiac output decrease. As a person ages, systolic blood pressure can increase up to 60-80 years, diastolic blood pressure - only up to 50 years.

In men, the increase in blood pressure with age is often gradual, but in men, especially after menopause, it is more dramatic. Reduced aortic elasticity is an independent predictor of cardiovascular mortality.

In the arteries, endothelial dysfunction is noted, its production of vasodilator factors decreases, and the ability to produce vasoconstrictor factors is retained.

Tortuosity and aneurysmal dilatation of capillaries and arterioles, their fibrosis, and hyaline degeneration develop, which leads to obliteration of the vessels of the capillary network, worsening transmembrane metabolism, and insufficiency of blood supply to the main organs, especially the heart.

Veins also change as a result of sclerosis of the walls and valves, atrophy of the muscle layer. The volume of venous vessels increases.

As a result of coronary circulatory insufficiency, dystrophy of myocardial muscle fibers, their atrophy and replacement with connective tissue develops. There is degeneration of collagen, which is the main structural component.

Collagen becomes more rigid, therefore the extensibility and contractility of the myocardium decreases. Cardiomyocytes die and are replaced with connective tissue, which progresses with age.

Developing sclerosis of the heart muscle in the elderly contributes to a decrease in its contractility and expansion of the cavities of the heart. Atherosclerotic cardiosclerosis is formed, leading to heart failure and heart rhythm disturbances.

A “senile heart” is formed, which is one of the main factors in the development of heart failure due to changes in neurohumoral regulation and prolonged myocardial hypoxia.

Aortic stenosis with calcification is most often observed in old age.

In the sinus node, the number of pacemaker cells, the number of fibers in the left bundle branch and Purkinje fibers decreases, they are replaced by connective tissue.

A shift in the electrolyte balance in the muscle cells of the myocardium aggravates the decrease in its contractility, helps reduce excitability, and this causes a high frequency of arrhythmias in old age, increasing the tendency to develop bradycardia, weakness of the sinus node, and various heart blocks. With aging, systole lengthens and diastole shortens.

Structural and functional changes in the body, hormonal and metabolic disorders form the features of the clinical picture of cardiovascular diseases in elderly and senile people. With age, the neurohumoral regulation of microcirculation changes, the sensitivity of capillaries to adrenaline and norepinephrine increases.

Influence on the cardiovascular system of the autonomic nervous system weakens with age, but sensitivity to catecholamines, angiotensin and other hormones increases.

In old age, the blood coagulation system is activated , functional insufficiency of anticoagulant mechanisms develops, the concentration of fibrinogen and antihemophilic globulin increases, the aggregation properties of platelets increase - this contributes to thrombus formation, which plays a significant role in the pathogenesis

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Age-related changes in the cardiovascular system, while not themselves the primary mechanism of aging, largely determine the intensity of its development.

They, firstly, significantly limit the adaptive capabilities of an aging organism, and secondly, they create the preconditions for the development of pathology, which is the main cause of human death - atherosclerosis, hypertension, coronary heart disease and brain disease.

Blood pressure

Most researchers agree that it is mainly the systolic level that increases with age. blood pressure (BP) blood (Fig. 29), while the diastolic changes slightly.

Rice. 29. Age dynamics of blood pressure on the right radial (A) and right femoral (B) arteries (arterial oscillography technique).
On the ordinate - maximum (1), minimum (2) and average dynamic (3) blood pressure, mm Hg. Art.; The abscissa axis is age, years.

With age, the average dynamic blood pressure, lateral, shock and pulse pressure also increases. Blood pressure is a complex parameter determined by vascular resistance and cardiac output. As can be seen from table. 27, the same level of blood pressure can be maintained at different age periods due to unequal shifts in general peripheral vascular resistance and cardiac output (Frolkis et al., 1977a, 1979).

Table 27. Indicators of hemodynamics and myocardial contractility in animals of different ages

It is of interest to compare hemodynamic parameters in phylogenetic terms, comparing them in organisms with different life expectancies. It is noteworthy that in short-lived species (rats, rabbits) blood pressure does not change significantly, while in longer-lived species (people, dogs) it increases.

It was noted that the increase in blood pressure is mainly associated with age-related changes in the vascular system - loss of elasticity of large arterial trunks, increase in peripheral vascular resistance. A decrease in cardiac output against the background of an increase in vascular resistance protects against a sharp increase in blood pressure.

There are differences in age-related changes in human blood pressure in different countries and in different regions of the Russian Federation. Thus, the lowest level of systolic pressure in old men and women is in Abkhazia, and then in Ukraine, Moldova; higher among residents of Belarus and Lithuania. Residents of Armenia and Kyrgyzstan have lower blood pressure than Muscovites and Leningraders (Avakyan et al., 1977).

With age, there is a decrease in venous blood pressure. According to Korkushko (1968b), when it is measured in a bloody manner using a Waldmann apparatus in the median vein in the area of ​​the elbow with a horizontal body position in the age group of 20-40 years, the level of venous pressure is on average 95 ± 4.4 mm water. Art., in the seventh decade - 71 ± 4, in the eighth - 59 ± 2.5, in the ninth - 56 ± 4.4, in the tenth - 54 ± 4.3 mm water. Art. (R
Expansion of the venous bed, decrease in tone, and elasticity of the venous wall are the determining factors in the decrease in venous blood pressure with age. A decrease in muscle tone and a decrease in the suction effect of the chest are also known to have an effect.

Rhythmic activity of the heart and its electrical activity

Aging is characterized by a slowdown in the rhythmic activity of the heart. It should be noted that there are significant individual differences. The slowdown in cardiac rhythm in old age is associated to a certain extent with a decrease in sinus automatism.

Bear (1979), by removing electrical potentials from pacemaker cells located at the mouth of the right vena cava, showed that their frequency decreases significantly with old age. However, a decrease in sinus automatism alone cannot explain the slowing of heart rate in old age. The fact is that the heart rate in the myocardial strips is much lower than in the heart in situ.

In slowing down the heart rate, the weakening of sympathetic extracardiac influences is of great importance. Thus, after the administration of beta-blockers in old animals, the slowdown in heart rate is less pronounced than in young animals. Certain changes also occur in the electrical activity of cardiocytes (Shevchuk, 1973).

Thus, the membrane potential of the myocardial fibers of the isolated right atrium was 78.6 ± 1.1 mV in adult animals, 81.9 ± 2.9 mV in old animals, PP - 96.9 ± 1.3 and 93.0 ± 0.7 mV, respectively. Noteworthy is the pronounced decrease in overshoot in old age, which was 18.3 ± 0.9 mV in adult rats and 12.1 ± 1.3 mV in old rats (p
A change in the repolarization process is also indicated by the results of electrocardiographic studies - a decrease in the main vector of the G loop, a discrepancy between the main vector of the ventricular complex loop (QRS) and the T loop.

With age, the process of depolarization also changes, and the QRS complex widens. Despite the development of age-related pulmonary emphysema, the electrical axis of the heart is deviated to the left, which indicates predominant changes in the myocardium of the left ventricle.

Noteworthy is the fact that the overall bioelectrical activity of the myocardium, according to vectorcardiography, changes unevenly in different age groups. It reaches its greatest increase in the sixth and seventh decades, after which it declines.

Partial analysis of the vectorcardiogram shows uneven changes in the right and left parts of the heart. Starting from the fifth decade, the activity of the left ventricle of the heart predominates. These conclusions coincide with morphological data on the development of left ventricular hypertrophy.

With age, the electrical systole of the heart lengthens. For example, according to our data, at the age of 20-40 years its duration is 0.368 ± 0.0067 s, in the tenth decade - 0.396 ± 0.008 s with the due 0.358 ± 0.0056 s (p
The conditions for the propagation of excitation in the atria worsen (expansion, flattening, deformation of the P wave). Atrioventricular conduction and the spread of excitation throughout the ventricular myocardium slow down somewhat.

These changes can be made depending on the age-related characteristics of the structure and metabolic processes in the conduction system of the heart. However, it should be emphasized that in comparison with other parts of the heart, the conduction system of the heart changes to a lesser extent.

Cardiac output

There is a close relationship between cardiac output and basal metabolic rate. Savitsky (1974) considers the connection between minute blood volume (MBV) and general metabolism is so close that, based on the basal metabolism, they derived formulas for calculating the proper IOC values. Most researchers come to the conclusion that cardiac output decreases in old and senile age (Fig. 30).

Rice. 30. Changes in basic hemodynamic parameters with age (study with T-1824 dye dilution).
Along the ordinate - SV, ml (A), SV, ml/m2 (B), minute blood volume, l/min (C) and SI, l*min-1*m-2 (D); The abscissa axis is age, years.

According to Brendfonbrener et al. (Brandfonbrener et al., 1955), a decrease in cardiac output has been noted since the third decade, and from 50 years of age and older, cardiac output decreases by 1% per year due to systolic volume and a slight decrease in the number of heart contractions (the dye dilution method was used - Evans blue ).

It was noted that the decrease in cardiac output was more pronounced than the decrease in oxygen consumption and CO2 emissions (oxygen consumption decreased by 0.6% per year). Strandell (1976) believes that the decline in cardiac output with age is associated with a decrease in oxygen consumption.

Tokar (1977) also observed a decrease in cardiac output in elderly people (dye dilution technique). In young people cardiac index (SI) was equal to 3.16 ± 0.19 l*min-1*m-2, in the elderly - 2.53 ± 0.11, in the old - 2.46 ± 0.09 l*min-1*m-2, the shock index - respectively 46.5 ± 2.6, 42.2 ± 1.8 and 39.6 ± 1.4 ml/m2.

Moreover, in older people compared to young people, a decrease in IOC was associated with a decrease number of heartbeats (HR), while in the old ones there was a significant decrease in SV.

In table 27 presents data on changes in hemodynamic parameters during aging in rats, rabbits and dogs (Frolkis et al., 1977b). They showed a significant decrease in minute blood volume and cardiac index. It is important that these animals do not suffer from spontaneous atherosclerosis, whereas it is known that people over 60 years of age almost always have atherosclerosis to one degree or another.

The decrease in cardiac output in old animals suggests that this is an age-related rather than a pathological phenomenon. It is also noteworthy that in different species of animals the participation of changes in the rhythm of heart contractions in the mechanism of the fall in cardiac output varies.

It has been found that with age, the functional reserve of cardiac output decreases above the basal level during submaximal physical activity (Korkushko, 1978; Strandell, 1976). Experimental data also indicate a limitation in the ability to adapt to loads (Frolkis et al., 1977b).

With experimental coarctation of the aorta in old animals, acute heart failure often develops, in 48% of cases. As can be seen from Fig. 31, 4-6 days after coarctation of the aorta in the so-called emergency phase in old animals, IOC, SV, and the maximum rate of increase in intraventricular pressure drop significantly.

Rice. 31. Systolic pressure in the left ventricle of the heart (L), the maximum rate of increase in intraventricular pressure (B) and the index of myocardial contractility (C) in% of the initial values ​​in adult (I) and old (II) rats on the 4th-6th ( 1) and 14-16 (2) days after experimental coarctation of the aorta.

With age, basal metabolism decreases. That is why a decrease in minute blood volume in elderly and old people is considered by some to be a natural reaction of the cardiovascular system to a decrease in tissue demands for oxygen delivery (Burger, 1960; Korkushko, 1968a, 1968b, 1978; Strandell, 1976; Tokar, 1977).

However, the decrease in oxygen consumption falls less than cardiac output, and this contributes to the occurrence of circulatory hypoxia. Compensatory mechanisms aimed at optimal tissue oxygen supply with reduced cardiac output are an increase in the arteriovenous oxygen difference and a change in the oxyhemoglobin dissociation curve (shift to the right).

In elderly and elderly people, against the background of reduced cardiac output, active regional redistribution of organ fractions of cardiac output is observed. Despite the decrease in IOC, the cerebral and coronary fractions of cardiac output are quite high (Mankovsky, Lizogub, 1976), while the renal (Kalinovskaya, 1978) and hepatic (Landowne et al., 1955; Kolosov, Balashov, 1965) are significantly reduced.

Absolute values central blood volume (CBC) do not change with age. However, his attitude towards circulating blood mass (CBM) indicates a relative increase. At the same time, an increase in SV in relation to the CTC was noted (Korkushko, 1978).

All this indicates a change in the conditions of blood flow to the heart and its deposition in the intrathoracic area. The relative increase in central blood volume in elderly and senile people is associated with an increase in the residual blood volume in the cavities of the heart. It is also important to increase the capacity (volume) of the aorta, its ascending part and arch.

MCC practically does not change with age. The ratio of the mass of circulating blood to the minute volume of blood gives an idea of ​​the time of complete blood circulation. This figure increases with age. At the same time, a slowdown in blood flow time was also noted in other areas of the vascular system: hand-ear, hand-lungs, lungs-ear; the time characterizing the central volume (intrathoracic) of blood circulation increases (Fig. 32).

Rice. 32. Age-related changes in blood flow speed.
Along the ordinate axis - the time of intrathoracic (A) and complete (B) blood circulation and blood flow in the arm-lung (C), lung-ear (D) and arm-ear (E) section, s; The abscissa axis is age, years.

N.I. Arinchin, I.A. Arshavsky, G.D. Berdyshev, N.S. Verkhratsky, V.M. Dilman, A.I. Zotin, N.B. Mankovsky, V.N. Nikitin, B.V. Pugach, V.V. Frolkis, D.F. Chebotarev, N.M. Emanuel

The heart has two sides - the atria. The right atrium pumps blood to the lungs to take in oxygen and get rid of carbon dioxide. The left atrium delivers oxygen-rich blood to the body.

Blood flows from the heart through arteries, which branch and become smaller and smaller as they travel through the tissues. In tissues, they become small capillaries.

Capillaries are where the blood gives oxygen and nutrients to the tissues and receives carbon dioxide and waste products back from the tissues. The vessels then begin to come together into large veins, which return blood to the heart.

Age-related changes in the heart

The heart has a natural pacing system that controls the heartbeat. Some of the pathways in this system may develop fibrous tissue and fatty deposits (cholesterol). The heart muscle loses some of its cells.

These changes can cause your heart rate to slow.

A slight increase in the size of the heart, especially the left ventricle, is not uncommon. The wall of the heart thickens, so the amount of blood the chamber can contain may actually decrease despite the overall size of the heart increasing. The heart may fill with blood more slowly.

Cardiac changes usually cause changes in the ECG. The ECG of a normal, healthy elderly person will be slightly different from the ECG of a healthy young adult. Rhythm abnormalities (arrhythmias), such as atrial fibrillation, are more common in older people. They may be caused by heart disease.

Normal changes in the heart also relate to the accumulation of the “aging pigment” lipofuscin in it. The heart muscle cells degenerate slightly. The valves inside the heart that control the direction of blood flow thicken and become stiffer. Heart murmurs are caused by stiffness of the valves quite often in old age.

Age-related changes in blood vessels

Receptors called baroreceptors monitor blood pressure and make changes to help the body keep blood pressure essentially the same when a person changes position or pace of activity. Baroreceptors become less sensitive with aging. This may explain why many older people suffer from orthostatic hypotension, a condition in which blood pressure drops when a person moves from lying or sitting to standing. This leads to dizziness because blood flow to the brain is reduced.

The walls of the capillaries thicken slightly. This may result in slightly slower rates of metabolism and waste.

The main artery of the heart (aorta) becomes thicker, stiffer, and less flexible. This is probably due to changes in the connective tissue of the walls of blood vessels. This raises blood pressure and causes the heart to pump harder, which can cause the heart muscle to thicken (hypertrophy). Other arteries also thicken and become stiffer. In general, most older people experience a mild increase in blood pressure.

Age-related changes in blood

The blood itself changes slightly with age. Normal aging leads to a decrease in the total amount of water in the body. As part of this, the fluid participating in the blood flow is reduced, so the blood volume is slightly reduced.

The number of red blood cells in the blood (and, accordingly, hemoglobin and hematocrit) decreases. This contributes to rapid fatigue. Most white blood cells remain the same, although some white blood cells responsible for immunity (lymphocytes) decrease in number, reducing their ability to fight bacteria. This reduces the body's ability to resist infection.

Impact of age-related changes

Under normal circumstances, the heart continues to supply sufficient blood to all parts of the body. However, aging of the heart may somewhat reduce the ability to tolerate increased stress, since age-related changes have reduced the ability to pump additional blood into the heart, thus reducing the reserve functions of the heart.

Some factors that can increase the workload of the heart:

Angina (chest pain caused by a temporary decrease in blood flow to the heart muscle), shortness of breath on exertion, and heart attacks can lead to coronary artery disease.

Various types of abnormal heart rhythms (arrhythmia) may occur.

Anemia is also possible due to malnutrition, chronic infections, loss of blood from the gastrointestinal tract, or complications of other diseases or side effects of various medications.

Atherosclerosis (hardening of the arteries) is a very common phenomenon. Fatty deposits (cholesterol plaques) inside blood vessels cause them to narrow and can completely block the blood vessels.

Heart failure is also very common among older people. In people over 75 years of age, congestive heart failure is 10 times more common than in younger adults.

Coronary heart disease is quite common, very often resulting from atherosclerosis.

Diseases of the heart and blood vessels are also quite common in older people. Common disorders include high blood pressure and orthostatic hypotension.

Heart valve diseases are quite common. Aortic stenosis, or narrowing of the aortic valve, is the most common valve disease in old age.

A transient ischemic attack (TIA) or stroke can occur if blood flow to the brain is disrupted.

Other heart and blood vessel problems include the following:

Deep vein thrombosis

Peripheral vascular disease resulting in intermittent pain in the legs when walking (claudication)

Prevention of age-related changes in the cardiovascular system

You can help your circulatory system (heart and blood vessels). Cardiovascular disease has risk factors that you should monitor and try to reduce:

High blood pressure,

Eat heart-healthy foods that are low in saturated fat and cholesterol, and control your weight. Follow your doctor's recommendations for treating high blood pressure, high cholesterol, or diabetes. Reduce your tobacco consumption or quit smoking altogether.

Exercise can help prevent obesity, and it helps people with diabetes control their blood sugar levels. Exercise can help you maintain your abilities for as long as possible and reduce stress.

Regular examinations and examinations of your heart are necessary:

Check your blood pressure. If you have diabetes, heart disease, kidney disease, or other medical conditions, your blood pressure should be checked more closely.

If your cholesterol levels are normal, you should have them checked every 5 years or more often. If you have diabetes, heart disease, kidney disease, or other medical conditions, your cholesterol levels should be checked more closely.

Moderate exercise is one of the best things you can do to keep your heart and the rest of your body healthy for as long as possible. Check with your healthcare provider before starting a new exercise program.

Exercise moderately and within your capabilities, but do it regularly.

People who eat less fat and smoke less tend to have fewer blood pressure problems and less heart disease than fatty food eaters who smoke.

Age-related changes in the circulatory system

Age-related changes in the circulatory system largely determine the nature and pace of aging. They limit the body's adaptive capabilities, worsen the functional state of organs, and create preconditions for the development of diseases. With aging, the structure of the vascular wall changes. Large arteries are the first to change. The inner lining of the vessel becomes denser, sclerosed, the muscle layer atrophies, and the elasticity of the vascular wall decreases. A decrease in vascular elasticity and an increase in peripheral resistance cause an increase in blood pressure (BP), mainly systolic. Usually it is moderately expressed.

Pulse tension increases. Venous pressure (VP) decreases with age. In older people, the number of functioning capillaries decreases, which contributes to a deterioration in the blood supply to organs and a decrease in metabolic rate. The blood supply to the heart is also disrupted. As a result, dystrophic changes appear in the heart muscle, and then the connective tissue grows, and progressive cardiosclerosis develops - “senile heart”.

The neurohumoral regulation of the cardiovascular system is disrupted. All this leads to rhythm disturbances, deterioration of myocardial contractile function, and circulatory disorders. Hemodynamics are rearranged, the speed of blood flow slows down in various parts of the cardiovascular system, and local blood circulation is redistributed.

Age-related changes in blood flow

Age-related changes in the cardiovascular system largely characterize the nature and pace of human aging. As a person ages, significant changes in the cardiovascular system occur.

Elastic arteries (aorta, coronary, renal, cerebral arteries) and the arterial wall change significantly due to compaction of the inner lining, deposition of calcium salts and lipids in the middle lining, atrophy of the muscle layer, and decreased elasticity.

This leads to thickening of the arterial walls and a constant increase in peripheral vascular resistance, an increase in systolic blood pressure, and an increase in the load on the ventricular myocardium; the blood supply to the organs becomes less than adequate.

In elderly and senile age, a number of hemodynamic features are formed: mainly systolic blood pressure (blood pressure) increases, venous pressure, cardiac output, and later cardiac output decrease. As a person ages, systolic blood pressure can increase over the course of a lifetime, while diastolic blood pressure can only increase up to 50 years of age.

In men, the increase in blood pressure with age is often gradual, and in women, especially after menopause, it is more dramatic. Reduced aortic elasticity is an independent predictor of cardiovascular mortality.

In the arteries, endothelial dysfunction is noted, its production of vasodilator factors decreases, and the ability to produce vasoconstrictor factors is retained. Tortuosity and aneurysmal dilatation of capillaries and arterioles, their fibrosis, and hyaline degeneration develop, which leads to obliteration of the vessels of the capillary network, worsening transmembrane metabolism, and insufficiency of blood supply to the main organs, especially the heart.

Veins also change as a result of sclerosis of the walls and valves, atrophy of the muscle layer. The volume of venous vessels increases.

As a result of coronary circulatory insufficiency, dystrophy of myocardial muscle fibers, their atrophy and replacement with connective tissue develops. The heart exhibits degeneration of collagen, which is the main structural component. Collagen becomes more rigid, therefore the extensibility and contractility of the myocardium decreases. There is a progressive death of cardiomyocytes with age and their replacement with connective tissue.

Developing sclerosis of the heart muscle in the elderly contributes to a decrease in its contractility and expansion of the cavities of the heart. Atherosclerotic cardiosclerosis is formed, leading to heart failure and heart rhythm disturbances. A “senile heart” is formed, which is one of the main factors in the development of heart failure due to changes in neurohumoral regulation and prolonged myocardial hypoxia.

Aortic stenosis with calcification is most often observed in old age.

In the sinus node, the number of pacemaker cells, the number of fibers in the left bundle branch and Purkinje fibers decreases, they are replaced by connective tissue.

A shift in the electrolyte balance in the muscle cells of the myocardium aggravates the decrease in its contractility, helps reduce excitability, and this causes a high frequency of arrhythmias in old age, increasing the tendency to develop bradycardia, weakness of the sinus node, and various heart blocks. With aging, systole lengthens and diastole shortens.

Structural and functional changes in the body, hormonal and metabolic disorders form the features of the clinical picture of cardiovascular diseases in elderly and senile people. With age, the neurohumoral regulation of microcirculation changes, the sensitivity of capillaries to adrenaline and norepinephrine increases. The effect on the cardiovascular system of the autonomic nervous system weakens with age, but sensitivity to catecholamines, angiotensin and other hormones increases.

In old age, the blood coagulation system is activated, functional insufficiency of anticoagulant mechanisms develops, the concentration of fibrinogen and antihemophilic globulin increases, the aggregation properties of platelets increase - this promotes thrombus formation, which plays a significant role in the pathogenesis of atherosclerosis, coronary heart disease and arterial hypertension.

When lipid metabolism is disturbed during the aging process of the body, there is a general increase in fat and cholesterol, i.e. atherosclerosis begins to develop. Impaired carbohydrate metabolism is associated with the fact that with age, glucose tolerance decreases, insulin deficiency develops, and this leads to a more frequent development of diabetes mellitus.

In addition, due to disruption of the metabolism of vitamins C, B and B 6, E, polyhypovitaminosis develops, which contributes to the development of atherosclerosis. Functional and morphological changes in the nervous, endocrine, and immune systems lead to the development of cardiovascular diseases, which is why diseases of the cardiovascular system occur so often in elderly and elderly people.

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/ Age-related features of blood circulation

Age-related features of blood circulation.

What changes does the circulatory system undergo during the growth and development of the body?

To answer this question, let us turn to the characteristics of blood circulation in the fetus. The main distinguishing feature of the development of blood circulation in the latter is the presence of placental circulation and the absence of pulmonary respiration, as well as the parallel connection of both halves of the heart. The transition to placental circulation is accompanied by serious functional changes in the fetal cardiovascular system.

Modern ideas about fetal blood circulation have been formulated since the time of the discoverer of the systemic circulation, Harvey.

Blood, saturated with nutrients and oxygen, enters the fetus through the umbilical vein from the placental villi, where gas exchange occurs. The continuation of the umbilical vein is the so-called duct of Arantius. Before or after anastomoses with the portal vein, it gives several branches into the liver parenchyma and then flows into the inferior vena cava. In the inferior vena cava, arterial blood from the placenta mixes with venous blood from the lower extremities, intestines, and pelvis. Due to the presence of a valve-shaped fold in the right atrium, about 60% of all blood from the inferior vena cava is directed through the foramen ovale to the left atrium, left ventricle and the aorta. The remaining blood from the inferior and superior vena cava enters the right ventricle and pulmonary artery. Only 25% of all blood circulating in the body flows through the fetal lungs, which is explained by the high resistance in the pulmonary artery system. The pulmonary arteries have a pronounced muscular layer and are in a spasmodic state. In the fetus, the pulmonary artery is connected to the aorta by a wide arterial duct through which blood enters the descending aortic arch below the origin of the vessels that deliver blood to the head and upper extremities of the fetus. The descending aorta carries blood to the lower parts of the body. In this regard, the liver, heart, organs located in the head, and upper limbs are in the most favorable conditions for supplying oxygen to the fetus, which contributes to their rapid development.

After the birth of a child, a sharp restructuring of the circulatory system occurs. Cutting the umbilical cord at the time of birth disrupts the connection between the fetus and the mother's body. When a newborn takes his first breath, a reflex expansion of the lungs occurs, and the pulmonary circulation begins to function. Blood is sent through the pulmonary artery to the lungs, bypassing the ductus arteriosus, which also contracts reflexively and soon turns into a connecting cord. Increased pulmonary blood flow increases pressure in the left atrium, and cessation of placental circulation reduces pressure in the right atrium, which leads to closure of the foramen ovale.

The most active functioning and morphological improvement of the cardiovascular system occurs during the first three years of a child’s life, but in the future the continuous, albeit uneven, development of the circulatory organs continues.

After birth, the child’s heart grows and enlarges, and morphogenesis processes occur in it. The heart of a newborn has a transverse position and a spherical shape, this is explained by the fact that the relatively large liver makes the vault of the diaphragm high, so the heart of the newborn is located at the level of the 4th left intercostal space. Under the influence of sitting and standing, by the end of the first year of life the diaphragm lowers and the heart takes an oblique position. By 2-3 years, the apex of the heart reaches the level of the 5th rib, and in 10-year-old children the borders of the heart are the same as in adults.

Height during the first year of life, the growth of the atria outstrips the growth of the ventricles, and only after 10 years does the growth of the ventricles begin to exceed the growth of the atria.

The heart mass grows most intensively in the first year of life; by eight months the heart mass doubles, by three years it triples, by 5 it increases 4 times, and at 16 years it increases 11 times.

At the same time, the heart mass in boys exceeds this figure in girls in the first years of life, but on the contrary, due to the onset of a period of increased growth in girls, its mass becomes greater than in boys. By the age of 16, girls’ hearts again begin to lag behind boys’ hearts in mass.

Heart rate (HR) in the fetus it ranges from 120 to 150 per minute. In the first 2 days after birth, heart rate is slightly lower than intrauterine, which is explained by an increase in intracranial pressure, a change in heat production due to the transition to an environment with a lower temperature, and finally, inhibition of sympathetic influences. In the following week, heart rate increases slightly per beat per minute. Subsequently, heart rate decreases with age. For example, in preschool children at 6 years old it is 95 beats/min, in schoolchildren 7-15 years old it varies within minutes, in adults it is beats/min.

A slowdown in heart rate is the result of a change in the lability of the sinus node and the development of more advanced forms of neurohumoral regulation of the heart. An increase in the tonic influence of the vagus nerve leads not only to a current decrease in heart rate, but also changes the metabolism of the sinus node, leading to a persistent decrease in its lability with age.

To assess the functional state of the heart, determining the systolic (stroke) and cardiac output is crucial.

Amount of blood ejected by the heart of a newborn with one contraction, 2.5 cubic meters. cm. By 1 year it increases 4 times and amounts to 10.2 cubic cm, by seven years - already 9 times, and by 12 years - 16.4 times. The minute volume of blood flow (MVF) also increases, mainly due to an increase in systolic volume. However, the deviation of the IOC value from mass (weight), which characterizes the body’s need for blood, is greater the younger the child’s age.

It is generally accepted that both systolic and diastolic blood pressure increase with age. In newborns, blood pressure is significantly lower than in adults. This is explained by the fact that in children of this age the arteries have a larger lumen width in relation to the mass of the heart, the total weight and height of the child. Venous vessels, on the contrary, are somewhat narrowed. The ratio of the diameters of venous and arterial vessels at this age is 1:1, while in adults it is 1:2.

Having reached a value of 70-72 mmHg. Art., the pressure then remains unchanged for a long period and only increases slightly in old age due to the loss of elastic properties of the walls of blood vessels and an increase in peripheral resistance.

It should be noted that the data presented are contradictory. These values, obtained in different countries, in different regions of our country, are different and depend on living conditions - for example, the physical development of a person. Thus, the blood pressure of natives of the south is lower than that of children from the northern regions (residents of Armenia and Kyrgyzstan have lower blood pressure than Muscovites).

Age-related characteristics of the cardiovascular system's response to physical activity.

Of particular interest may be the peculiarities of changes in the response of the cardiovascular system in ontogenesis under various conditions of the body, in particular under the influence of physical activity. In this case, increasing cardiac output is crucial in ensuring the required level of blood circulation. The younger the child, the more often the increase in minute blood volume occurs due to an increase in heart rate. The heart rate during exercise in children can reach, and in 8-year-old children the heart rate increases by 50%, in 17-year-olds by 70% relative to the initial level. The maximum increase in blood pressure in 8-year-olds is 14 mmHg. Art., and summer ones by 30 mm Hg. Art.

In older children, during physical work the work-in period is shortened, that is, the time to achieve the maximum change in hemodynamics. The older the child, the more significant changes in blood circulation can occur under the influence of physical activity. The duration of the recovery period also shortens with the age of the child.

With the growth and development of the body, its total energy expenditure increases and the need for oxygen increases. Body size increases, and the increasing oxygen demand is ensured by the development of systems that deliver and transport oxygen in the lungs and blood. Metabolic processes in tissues are improved. As the body further develops individually, neurohumoral regulation and coordination of the mechanisms that serve the exchange of gases between the external environment and tissues improve.

Age-related changes in the circulatory system

Age-related changes in blood vessels and the heart significantly limit their adaptive capabilities and create preconditions for the development of diseases.

Changes in blood vessels

The structure of the vascular wall changes with age in each person. The muscle layer of each vessel gradually atrophies and decreases, its elasticity is lost, and sclerotic compactions of the inner wall appear. This greatly limits the ability of blood vessels to expand and narrow, which is already a pathology.

Large arterial trunks, especially the aorta, are primarily affected. In older and older people, the number of active capillaries per unit area decreases significantly. Tissues and organs cease to receive the amount of nutrients and oxygen they need, and this leads to their starvation and the development of various diseases.

Features of hemodynamics in old age

With age, with the loss of elasticity of large vessels and an increase in the peripheral resistance of small vessels, the

blood pressure (especially systolic). Venous

pressure decreases. This is due to a weakening of tone, a decrease in the elasticity of the venous walls, which leads to an expansion of the total lumen of the venous bed.

In old and senile age, the cardiac output decreases (minute volume is the amount of blood ejected by the heart in one minute). This decrease is mainly due to a slower heart rate and a decrease in stroke volume. Since basal metabolism decreases with age, a decrease in cardiac output can be considered as a natural reaction of the body to a decrease in tissue demand for oxygen.

In elderly and elderly people, against the background of reduced cardiac output, an active redistribution of regional blood circulation is observed. At the same time, cerebral and coronary circulation remains almost unchanged, while renal and hepatic circulation are significantly reduced.

This restructuring of the hemodynamic system partially compensates for the increase in energy consumption during cardiac operation in conditions of increased resistance to cardiac output associated with an increase in peripheral vascular resistance.

Decreased contractility of the heart muscle

The older a person gets, the more muscle fibers of the heart muscle atrophy. The so-called “senile heart” develops. Progressive myocardial sclerosis occurs, and in place of the atrophied muscle fibers of the cardiac tissue, fibers of non-working connective tissue develop. The strength of heart contractions gradually decreases, an increasing disturbance of metabolic processes occurs, which creates conditions for energetic-dynamic heart failure in conditions of intense activity,

As a result of all the above processes, the physical performance of the heart decreases with age. This leads to a limitation of the range of reserve capabilities of the body and to a decrease in the efficiency of its work.

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Age-related changes in the blood supply to the kidneys in people over 40 years old

Kidneys undergo changes during the aging process in accordance with changes in the circulatory system.

Due to sclerotic changes in the vessels, significant areas of the kidneys in old age become ischemic, and in an 80-year-old person, 30 to 40% of the nephrons are sclerotic.

In old people, the volume of glomerular filtration, plasma renal blood flow, and the concentrating ability of the kidneys are reduced to almost 50%. For example,

The decrease in effective renal blood flow after age 40 is expressed as follows:

effective renal blood flow = 840- 6.44 number of years;

decrease in glomerular filtration after 40 years:

glomerular filtration =153.2-0.96-number of years.

However, the threshold of plasma glucose concentration for excretion in the kidneys may even be increased, so that in elderly people with diabetes, glycosuria may not be sufficiently pronounced. Drugs that are excreted in the urine in young people can accumulate in the body of old people due to insufficient excretory function of the kidneys. Of the 185 metabolic products determined in human urine, at least 60 change concentration with aging.

Many old people suffer from nocturia (excretion of a large part of the daily amount of urine at night), which correlates with the above-mentioned insufficiency of the concentrating ability of the kidneys.

The decrease in the ability of the kidneys to concentrate urine is due to the fact that sclerosis of the arteries and vessels of the glomeruli in the renal cortex is accompanied by increased blood flow in the medulla, in the straight arterioles and the network of capillaries they form.

The increase in blood flow in the renal medulla increases the leaching of osmotically active substances from the interstitial space of the medulla, reducing water reabsorption and the effectiveness of the counterflow-rotation system.

The decrease in the ability of the kidneys to retain water in the body is compensated by the increasing secretion of ADH by the hypothalamic-pituitary system.

Increased secretion of ADH is associated with an increasing sensitivity of osmoreceptors to osmotically active substances in the blood and tissue fluid in humans after 50 years.

Thanks to these compensatory mechanisms, the intravascular and extracellular volumes of body fluids and their composition in the elderly are little changed.

Compatibility of the development of motor and mental activity of a child in the first half of life. Joint development of motor and mental activity of a child in the second half of life. Simultaneous formation of the first and second signaling systems of a child under 3 years of age.

Physiologists N.A. Bernstein and G. Shepherd believe that “motor activity is a kinetic factor that largely determines the development of the body and nervous system, along with the genetic factor and the influence of sensory multimodal information. Full physical development, the formation of correct posture, motor qualities, optimal motor stereotype through developmental movement is inextricably linked with the harmonious consistent organization of the nervous system, its sensitive and motor centers, analyzers." Thus, according to scientists, the preschool education program "Physical Development and Health" should be equally aimed at the physical (physical) and neuropsychic development of the child.

V.A. Shishkina notes the extremely important role of movements for the development of the psyche and intelligence. “Impulses from working muscles constantly enter the brain, stimulating the central nervous system and thereby promoting its development. The more subtle movements a child has to perform and the higher level of coordination of movements he achieves, the more successful the process of his mental development is. A child’s motor activity not only contributes to the development of muscle strength as such, but also increases the body’s energy reserves.” Scientists have established a direct relationship between the level of motor activity and their vocabulary, speech development, and thinking. They note that under the influence of physical exercise and physical activity in the body, the synthesis of biologically active compounds increases, which improve sleep, have a beneficial effect on the mood of children, and increase their mental and physical performance. “In a state of reduced motor activity, metabolism and the amount of information entering the brain from muscle receptors decrease. This worsens metabolic processes in brain tissue, which leads to disruption of its regulatory function. A decrease in the flow of impulses from working muscles leads to disruption of the functioning of all internal organs, primarily the heart, and affects the manifestations of mental functions and metabolic processes at the cellular level

Speaking about motor activity as the basis for the life support of a child’s body, E.Ya. Stepanenkova points out that it is she who influences the growth and development of the neuropsychic state, functionality and performance of the child. “During muscular work, not only the executive (neuromuscular) apparatus is activated, but also the mechanism of motor-visceral reflexes (i.e. reflexes from muscles to internal organs) of the work of internal organs, nervous and humoral regulation (coordination of physiological and biochemical processes in body). Therefore, a decrease in physical activity worsens the condition of the body as a whole: both the neuromuscular system and the functions of internal organs suffer.”

T.I. Osokina and E.A. Timofeeva also note in their studies that in the process of muscular activity the work of the heart improves: it becomes stronger, its volume increases. Even a diseased heart, they note, is significantly strengthened under the influence of physical exercise.

“The blood is cleared of carbon dioxide and saturated with oxygen in the lungs. The more clean air the lungs can hold, the more oxygen the blood will carry to the tissues. When performing physical exercises, children breathe much deeper than in a calm state, as a result of which the mobility of the chest and lung capacity will increase.”

The authors note that physical exercise in the fresh air especially activates gas exchange processes. A child, being systematically exposed to air for a long time, hardens, as a result of which the child’s body’s resistance to infectious diseases increases. Thus, summarizing all of the above, we can note physical activity as a biological need of the body, the degree of satisfaction of which determines the health of children, their physical and general development. “Movements and physical exercises will provide an effective solution to the problems of physical education if they act in the form of a holistic motor regime that meets the age and individual characteristics of the motor activity of each child.”

From about 30 years of age, irreversible changes associated with age begin in the heart and blood vessels. The older a person gets, the more pronounced they are. After fifty, all systems age, which determines the nature of these processes and affects the adaptive properties of the body. The article will discuss what age-related changes occur in the heart and blood vessels.

Changes in blood vessels

In older people, the morphological and anatomical structure of veins and arteries changes.

Transformations are most observed in large vascular trunks:

• the muscle layer partially atrophies;
• elasticity decreases;
• the intima becomes overgrown with sclerotic elements.

Such metamorphoses do not allow blood vessels to narrow and expand to the proper extent. This, in combination with changes in nervous regulation (innervation from the central nervous system is also weakened), changes the adaptive properties of hemocirculation.

Over time, the number of capillaries per unit area of ​​tissue decreases, and in the remaining ones the membrane walls thicken, which reduces transport processes and causes hypoxia.

Note. First, age-related changes occur in large blood vessels, and then in small (peripheral) ones. Transformations in the pulmonary arteries are observed in older people.

Blood circulation

As a rule, systolic pressure increases slightly with age (provided there are no chronic diseases of the cardiovascular system). This occurs due to a decrease in the elasticity of large vessels and an increase in resistance in distant capillaries. At the same time, the internal volume of large arteries increases, which prevents blood pressure levels from increasing significantly.

These changes occur rather slowly, and in some individuals there may be a genetic predisposition. However, they do not always lead to the development of diseases and may not have clinical manifestations; however, laboratory examination reveals abnormalities in hemodynamics.

Such processes are natural. The functional cardiac reserve gradually decreases, making it increasingly difficult for older people to cope with physical activity.

The activity of the myocardium weakens, disturbances in its functioning and the development of pathologies, for example, heart failure, are possible.

Venous pressure

As the tone of the vessels weakens, elasticity decreases and their diameter increases, the blood pressure in the veins gradually decreases. In older patients, doctors record a reduction in cardiac output, which is explained by a slowdown in heart rate and a weakening of heartbeats. This causes a decrease in blood ejection and a redistribution of peripheral blood circulation.

Note. Despite the general weakening of blood circulation in the brain and coronary vessels, even in most people the pressure remains at an acceptable level, while it decreases in other internal organs, such as the liver and kidneys.

Changes in the heart

The main component of myocardial cells is collagen. With age, its quantity in the valves increases, but its quality changes - it becomes less soluble. This causes its chemical stability, it becomes stiffer, and therefore the elasticity of tissues decreases.

As the human body ages, more and more lipofuscin is deposited in cells around nuclear membranes and processes. On histological examination, this is noticeable in the form of yellow or brown formations. The older a person is, the more substance is concentrated in the tissue.

Approximately every year its amount increases by 0.3% of the total mass of the heart muscle. Doctors believe that this is due to the products that are released when cellular structures die (ER tanks, mitochondria and lysosomes).

Normally, this does not cause any pathological conditions, but with a reduction in cardiac mass and an increase in the amount of lipofuscin, a condition called brown atrophy develops.

Important. Often, a decrease in cardiac mass is associated with general exhaustion of the body, which is typical for older people.

In addition to these processes, calcium deposits and fats accumulate in the mobile zone of the heart valves, the mass of cells and the number of nuclear structures become smaller. This leads to degeneration of the aortic and mitral valves. According to medical statistics, 30% of elderly people (aged 70 years and older) suffering from heart disease are diagnosed with valve calcification.

In addition to these processes, there are many different age-related changes that cause a decrease in myocardial contractility. This is primarily due to morphological transformations, which are combined into the general term “senile heart”.

In this case it is observed:

• decreased adaptive abilities;
• muscle atrophy;
• increase in the area of ​​weakly elastic tissues;
• decreased energy production in mitochondria;
• disruption of transmembrane transport of mineral components.

Features of response to physical activity

Decreased cardiac activity manifests itself in the inability to withstand significant physical activity. First of all, this consists of a lack of oxygen, the development of ischemic processes and the slow removal of carbon dioxide and metabolites from muscle tissue. The older a person gets, the more pronounced the hypertensive response to physical work is, and peripheral vascular resistance in this case undergoes minor changes.

In older people, the contractility of the heart decreases, the increase in stroke volume decreases, and the nervous and endocrine regulation of myocardial activity changes. All this significantly slows down the body’s recovery after physical exertion, therefore, in order to prevent health complications, doctors recommend dosed exercise or hard work, and, if possible, completely abandon grueling physical labor.

In addition to the indicated internal natural causes, other influences indicated in the table negatively affect the functioning of the heart in older people.

Table. Indirect factors affecting the functioning of the cardiovascular system:

Cause

Age-related changes in the cardiovascular system

There is no such anatomical or clinical concept as the senile heart. Death does not occur as a result of physiological aging of the heart. However, with age, a number of changes occur in the human heart, such as a decrease in the elasticity of the myocardial wall as a result of an increase in collagen content or calcification of the mitral valve ring, aortic and pulmonary valves. At the same time, the wall of the aorta and other arteries gradually loses its elasticity. These processes, which develop slowly or quickly in different people, may be genetically determined. They do not necessarily cause clinical disease, but lead to slow, gradual changes in hemodynamics. In this case, systolic blood pressure tends to increase due to increasing peripheral vascular resistance associated with loss of elasticity in the arteries, while diastolic pressure remains at the same level or decreases. These consequences of normal aging of the cardiovascular system lead to a slow decline in the functional reserve of the heart, which greatly reduces the ability of the cardiovascular system to cope with physical activity. The heart becomes weaker, pathological processes increasingly affect its function, and heart failure may develop.

Physiological aging of the entire organism can indirectly affect the heart. Older people are less resilient to environmental stress, infections and other adverse effects. In addition, with age, the mass of cells in vital organs decreases. This phenomenon has particular consequences for the kidneys, as their ability to excrete catabolites and drugs decreases as nephron mass decreases.

Age-related morphological changes in the heart

The most important molecular change in the heart involves collagen. Collagen is the main component of the valves, endocardium and epicardium, and is scattered between all myocardial cells. Although the amount of collagen in the heart increases with age, the main change is qualitative rather than quantitative. With aging, collagen becomes less soluble, chemically more stable and, most importantly, stiffer, and this affects both the contractility and distensibility of the heart.

Lipofuscin deposition is the most specific change in cardiac cells during aging. It is deposited as a yellow-brown pigment in aggregates of granules near the processes of the nuclei. The accumulation of lipofuscin increases in direct proportion to age with an intensity of 0.3% of cardiac muscle volume per year.

It is believed that the presence of lipofuscin is associated with breakdown products of intracellular organelles, such as mitochondria, lysosomes and endoplasmic reticulum. Lipofuscin appears to have no effect on myocardial function. When this is combined with a reduction in cardiac mass, the presence of large amounts of lipofuscin is called brown atrophy. However, reduction in cardiac mass is usually associated with concomitant wasting, and cardiac mass decreases in proportion to body weight.

With aging, the number of nuclei in heart valves decreases and lipids accumulate in the fibrous stroma. Degeneration and calcification are common. These changes occur mainly in the zone of maximum mobility of the valves, and with age the frequency and severity of these changes increase. The aortic valve is usually more involved in the pathological process than the mitral valve. During pathological examination, microscopically identifiable calcification is found in at least 1/3 of patients over 70 years of age.

Other age-related changes may occur in the mitral valve. Often there is a nodular thickening on the atrial surface of the valves along the line of application. Mucoid degeneration is common, especially in the posterior leaflet. These changes are morphologically identical to the myxomatous changes observed in young patients with mitral valve prolapse.

Myxomatous changes may also be due to other causes not related to age. Nodules can be detected on the aortic valves, and the frequency of these changes does not change with age, which makes it possible not to consider them purely age-related changes. Nodules are rare on the tricuspid and pulmonary valves.

Age-related changes in blood vessels

The development of blood vessels under the influence of functional load changes by the age of 30. Connective tissue grows in the walls of the arteries, which leads to their thickening. In elastic arteries this process is more pronounced than in other arteries.

After 60-70 years, in the inner lining of all arteries there are focal thickenings of collagen fibers, as a result of which, in large arteries, the inner lining approaches medium in size. In small and medium-sized arteries, the inner lining is less developed. The internal elastic membrane becomes thinner and splits with age. The muscle cells of the tunica media atrophy. Elastic fibers undergo granular disintegration and fragmentation, and collagen fibers proliferate. At the same time, in the inner and middle membranes, in older people, calcareous and lipid deposits appear, which progress with age. In the outer shell, in persons over 60-70 years of age, longitudinally lying bundles of smooth muscle cells appear.

Age-related changes in veins are similar to those in arteries. However, the restructuring of the human vein wall begins in the first year of life. By the time a person is born, in the middle tunic of the walls of the femoral and saphenous veins of the lower extremities there are only bundles of circularly oriented muscle cells. By the end of the first year of life, when the child stands on his feet and the distal hydrostatic pressure increases, longitudinal muscle bundles develop. The lumen of the vein in relation to the lumen of the artery is 2:1 in adults, 1:1 in children. The expansion of the lumen of the veins is due to less elasticity of the wall and increased blood pressure.