Nothing testifies to human he alth more reliably than indicators of the cardiorespiratory system. As you might guess from the name, we will talk about the relationship between the circulatory and respiratory systems in our body, their functions and purpose.
What role does
Even minimal physical activity is impossible without a mechanism for the coordinated transport of oxygen to the heart and brain. If cardiovascular diseases are suspected, the patient is referred for diagnostic procedures, the results of which will provide an objective picture of the state of the cardiorespiratory system. Specific changes in it lead to a malfunction of the whole organism. According to some data, the number of people suffering from diseases of the heart, blood vessels and lungs in Russia is almost 20 million people, of which more than a million are children under the age of 15.
The prevalence of pathologies of the cardiovascular system obliges modern society to study their pathogenesis and etiology, so the assessmentaerobic capacity of the body is a must. The cardiorespiratory system is a complex consisting of two different, but at the same time interconnected systems. To understand how the main processes of the body's vital activity proceed, consider the structure and principle of operation of each of them.
Cardiovascular system
Thanks to its constant and uninterrupted operation, blood circulation throughout the body is ensured. In the structure of the cardiovascular system, the main elements are the heart - a kind of pump that pumps blood, and blood vessels - hollow tubes through which blood is transported. In addition to blood, lymph flow is also important, which is conditionally considered part of the vascular system.
The nutrition of each cell with oxygen and the flow of metabolic processes depend on the state of the cardiorespiratory system. Interacting with the internal systems of the body, the heart and blood vessels immediately respond to any changes in the conditions of the internal environment to ensure maximum efficiency of their work.
Even during sleep and rest, the cardiorespiratory system does not stop working, continuing to satisfy the needs of tissues for oxygen. The heart, blood vessels, and lungs have diverse purposes. Why do we need a cardiorespiratory system? It performs the following functions:
- exchange;
- excretory;
- homeostatic;
- transport;
- protective.
Cardiovascularthe system delivers oxygen and nutrients to every cell in the body, removing carbon dioxide and metabolic end products from it. Blood moving through the arteries, veins and capillaries delivers hormones from the endocrine glands to their end receptors, is involved in maintaining a stable temperature regime and controls the pH of the body. It is the cardiovascular system that helps prevent dehydration and infectious diseases.
How is the cardiorespiratory process going
Many works of scientists are devoted to the study of methods for studying the state of the cardiorespiratory system. Independent work is also carried out by students of the relevant profile of medical universities. All these developments are of great importance. Thanks to research work, it became known what the cardiorespiratory system is and what processes take place in it.
The human heart consists of two atria, which act as receiving chambers, and two ventricles that pump blood. The heart as a pump promotes non-stop blood circulation through large and small vessels, which are the structure of the circulatory system. The blood flowing in the capillaries not only transports oxygen and nutrients to the internal organs and tissues, but also collects the products of their metabolism. With them she returns back to her heart. Such blood is called deoxygenated.
Liquid tissue enters the right atrium through the superior and inferior vena cava. Blood is sent from the right atrium to the rightthe ventricle, where it is pumped through an open valve into the pulmonary arteries, and from there directly to the right and left lungs. The right side of the heart is responsible for the pulmonary part of the blood circulation, therefore it sends the blood that has passed throughout the body to the respiratory organs for its subsequent reoxygenation. As soon as the lungs are filled with oxygen, the enriched blood leaves through the pulmonary veins and returns to the left atrium. Oxygenated blood enters here, which supplies oxygen to all tissues and organs, flowing from the open atrioventricular left mitral valve into the left ventricle and aorta, and then to all body tissues.
Natural ventilation - what is it?
The process of moving air in and out of the lungs is called breathing. Anatomical ventilation is provided by two stages - inhalation and exhalation. Air enters the lungs through the nose; the mouth is used when the need for air exceeds the amount that can be taken into the lungs through the nose. Moreover, it is more correct and more useful to breathe through the nose, since the air that passes through the nasal concha is warmed and cleared of dust, allergens, viruses and bacteria that are retained by the ciliary epithelium and the mucous membrane of the nasopharynx. Mouth breathing does not provide the same thorough filtering of the air mixture entering the body, which increases the likelihood of developing respiratory infections.
The smallest element of the human cardiorespiratory system is the pulmonary alveolus, the part of the lungs where gas exchange occurs. Alveoli are numerousrespiratory units. From the nose and mouth, air moves towards them through the pharynx, larynx, trachea, bronchi and bronchioles.
The lungs have no attachment to the ribs. The respiratory organs seem to be suspended due to the pleural cavity enveloping the lungs. They contain a thin layer of pleural fluid necessary to eliminate friction during respiratory movements. In addition, the pleural cavities are connected not only to the lungs, but also to the inner surface of the chest.
What happens when you exercise
The oxygen demand of the muscles increases suddenly with an increase in activity, against the background of which a large consumption of nutrients is required. In addition, there is an acceleration of metabolic processes, which leads to an increase in the amount of decay products. Prolonged physical activity provokes an increase in body temperature, the level of hydrogen ion concentration in soft tissues and blood, and a decrease in the acidity of the internal environment.
Regulation of breathing plays a huge role in increasing physical activity. Most often, changes in the level of muscle activity negatively affect the state of the cardiorespiratory system. One of the common phenomena is shortness of breath, which is experienced by people who do not have proper physical fitness. Increased loads lead to a sharp increase in the concentration of arterial carbon dioxide and the level of H+ ions in the blood. The signal about these changes is sent to the respiratory center, resulting in an increase in the frequency and depth of ventilation.
All specifiedspecific changes in the cardiorespiratory system help to achieve the main goal of meeting increased physical needs and ensuring maximum efficiency of its functioning.
Intensive lung work
To ensure proper pulmonary ventilation and transportation of gases, the body expends a lot of energy. Its predominant part is used by the respiratory muscles in the process of lung ventilation. If a person is inactive, at rest, only 2% of the total energy expended is utilized by the respiratory muscles. If the frequency of inhalations and exhalations increases, energy consumption also increases. During intense physical work, the respiratory system can use more than 15% of the energy. Oxygen is required by all its elements: diaphragmatic septum, intercostal muscles and abdominals.
The process of natural ventilation of the lungs is carried out at a high cost of energy, but even extreme physical activity does not lead to arbitrary inflow and outflow of air. This is the maximum arbitrary ventilation. There is an opinion that it is pulmonary ventilation that is the limiting factor during exhausting physical activity in athletes. The cardiorespiratory system, according to experts, works at full strength, which ultimately leads to the wasting of glycogen stores and fatigue of the respiratory muscles. These changes are observed during long training sessions, multi-kilometer runs, etc.
Scientists who conducted experimentswith rats, came to the conclusion that insufficiently “trained” rodents during intense physical activity decreased the level of glycogen in the respiratory muscles. And despite the fact that in the muscles of the hind limbs it remained practically unchanged, the test animal developed a cardiorespiratory syndrome, which is characterized by tachycardia, severe shortness of breath, and in severe cases, pulmonary edema.
The volume of air inhaled during physical activity can increase several times, and the airway resistance remains the same as that characteristic of the state of rest due to the expansion of the laryngeal fissure and bronchi. The blood entering the cardiovascular system does not lose the degree of oxygen saturation even with maximum effort. Thus, the cardiorespiratory system is able to meet the needs for intensive breathing during both short and long-term physical activity.
Be aware that excessive oxygen uptake can lead to some problems. Abnormally narrow airways or impaired airway patency can lead to specific changes occurring in the cardiorespiratory system. Asthma, for example, provokes constriction of the bronchioles and swelling of the mucous membrane, which ultimately increases the ventilation resistance force and provokes shortness of breath. The indicator characterizing the maximum performance of the cardiorespiratory system is the satisfactory condition of the respiratory organs. Although the relationship between exercise and airway obstructionpaths was established a long time ago, doctors still cannot determine the exact mechanism for the development of an asthmatic attack against a background of increased activity.
Pulse on the arm: how many beats is considered normal?
Heart rate is the simplest and at the same time informative indicator that is taken into account when conducting cardiorespiratory monitoring. Everyone knows how to measure the heart rate - you need to feel for bullets in the area of \u200b\u200bthe wrist or carotid artery and count the number of beats per minute. These areas reflect the amount of work performed by the heart to meet the increased demands of the body.
The difference in performance between a person at rest and a person during a cardiorespiratory load is obvious. On average, the heart rate is about 60-80 beats per minute. Interestingly, in athletes, the cardiorespiratory system at rest demonstrates more modest results. Their pulse rate can be 28-40 beats, which is considered the norm and is explained by the high level of training and the physical endurance developed over the years of training. In people who are much less likely to experience intense cardiorespiratory stress, the heart rate can reach 90-100 beats per minute.
With age, the pulse decreases. External factors (for example, high temperature, lack of oxygen, increasedatmospheric pressure, etc.). Against the background of an increase in the intensity of work, the pulse becomes faster. If the level of physical activity is under control (it can be measured using various devices), a special formula can be used to calculate the approximate amount of oxygen consumed.
Determining the intensity of labor in terms of oxygen consumption is not only accurate, but also the most appropriate when examining different people, or the same person, but under different circumstances. The maximum heart rate increases in proportion to the increase in the intensity of physical labor up to overwork. By the way, as this state is reached, the heart rate gradually stabilizes.
The maximum heart rate can be determined taking into account age, as it becomes lower as a person grows older. The heart rate drops at a rate of 1 beat per year starting at 10-15 years of age. At the same time, it should be borne in mind that individual indicators may differ significantly from the average values.
Circulation during exercise
The cardiorespiratory system is a complex structure in which one of the main roles belongs to the blood circulation. When a person begins to exercise or work, his blood flow is distributed differently. Under the influence of the sympathetic nervous system, blood leaves those vessels where its presence is not necessary at the moment, and goes to the muscles that are actively involved in the work. In a person who is at rest, cardiac outputblood in the muscles is only 15-20%, and when playing sports it can reach 85%. The blood supply to muscle tissues increases due to a decrease in the blood supply to the abdominal organs.
In the event of a change in temperature, the predominant amount of blood is directed to the skin. This is also taken care of by the sympathetic nervous system. The purpose of redistribution is to replace the heat that is released into the external environment by sending it from the depth of the body to the periphery. At the same time, increased skin blood flow automatically reduces the intensity of blood supply to muscle tissues. Not surprisingly, the performance of the cardiorespiratory system in individuals involved in sports in hot weather does not show good results.
The skeletal muscles involved in the work experience an acute need for more oxygen, which is satisfied by accelerated blood circulation due to sympathetic vascular stimulation in those areas where blood flow is temporarily limited. For example, the vessels leading to the organs of the digestive system can narrow, after which the blood flow is redirected to the muscles, which are in need of more blood. The vessels of the muscles expand, due to which there is a rush of blood. In the process of performing physical activity, the rate of metabolic reactions occurring in muscle tissues increases, which leads to the accumulation of metabolic decay products. An active metabolism causes an increase in acidity and temperature in the muscles.
Functionalitymyocardium
The medical name for the heart muscle is the myocardium. The thickness of the walls of the main human "motor" depends on what kind of load regularly falls on its chambers, of which the left ventricle is the most powerful. By contracting, it pumps out blood and sends it through the entire circulatory system. If a person is not active, but simply sits or stands, his myocardium will contract vigorously. This allows you to cope with the effect of gravity, which leads to the accumulation of blood in the lower extremities.
If the left ventricle is hypertrophied, that is, the thickness of its muscular wall is increased in comparison with other chambers of the heart, this means that the heart had to constantly work in conditions of increased demands. When playing sports or other intense loads, accompanied by increased breathing, myocardial activity becomes as active as possible. As the muscle's demand for blood increases, so does the requirement for the left ventricle, so over time it increases in size similar to skeletal muscle.
Coordination of heart contractions depends on the signal to perform the contraction. The conducting system of the heart is responsible for the implementation of this function. The myocardium has a unique ability: it is able to produce an electrical signal, allowing the muscle to contract rhythmically without neural or hormonal stimulation. The congenital heart rate is about 70-80 beats.
Cardiac disorders
To specific changes,occurring in the cardiorespiratory system include deviations that occur in normal cardiac activity. The most common disorder is a change in heart rate. The danger of such disorders is not the same. There are two types of arrhythmia - bradycardia and tachycardia. In the first case, we are talking about a slowdown in the heart rate, in the second - an increase in this indicator.
With bradycardia, the pulse is usually within 60 beats per minute, and with tachycardia it can exceed 100-120 beats. Against the background of these disorders, the sinus rhythm also changes. The myocardium can work satisfactorily, only its rhythm deviates from the norm, which affects blood circulation. Symptoms of arrhythmia are dizziness, nausea, weakness and a feeling of fatigue, weakness, anxiety, tremor of the limbs, faintness.
Another type of arrhythmia, which is no less common, is atrial fibrillation and flutter. With such deviations, patients feel additional myocardial contractions that occur due to impulses that occur outside the sinoatrial node. Atrial flutter, in which they contract at a frequency of 200-400 beats per minute, is a dangerous type of arrhythmia, in which the heart practically cannot cope with its main function and hardly pumps blood.
Ventricular paroxysmal tachycardia is an equally serious disorder requiring urgent medical attention. This violation is a serious threat to the life of the patient. With ventricular paroxysmal tachycardia, three or more prematureventricular contractions, which can lead to flicker. Unlike flutter, flicker does not allow the myocardium to control the process of ventricular tissue contraction. The heart loses its ability to pump blood. Ventricular fibrillation is often fatal in patients suffering from chronic heart failure and other diseases.
Severe forms of arrhythmia are a direct indication for the use of a defibrillator, which can return a satisfactory sinus rhythm. Measures of emergency treatment contribute to the restoration of breathing and the maintenance of life. When engaging in sports that require high cardiorespiratory endurance, a person may find themselves with a low heart rate. In this case, we are not talking about bradycardia. Tachycardia is not considered an increase in heart rate during active muscular work. Both bradycardia and tachycardia usually occur in people at rest.
Features of the cardiorespiratory system in children and adolescents
Some experts distinguish the so-called pubertal period of heart development, since it is during puberty that pronounced changes are observed in cardiovascular activity. Compared to the level of development of the cardiorespiratory system in children 7-10 years old, the cardiovascular apparatus in adolescents becomes more functional and resilient.
At the same time, the very process of the formation of the heart and blood vessels differs in representatives of different sexes. Girlsmyocardial mass increases faster, but less uniformly. In turn, the size of the heart and aorta in boys is larger than in girls. During puberty, profound changes occur in the structure of the heart muscle, the diameter of the fiber and nucleus increases. The myocardium grows rapidly, and the vessels are slower, due to which the lumen of the arteries in relation to the size of the heart becomes smaller. This change can lead to circulatory disorders and increased pressure during exercise.
Heart rate is a labile indicator that changes under the influence of internal and external factors (increase in air temperature, expression of emotions, sports training, etc.). At the same time, the pulse during physical work can increase to 160-180 beats per minute, which leads to an increase in the volume of blood expelled. The child's cardiorespiratory system is affected by mental stress, which is expressed by an increase in heart rate, a temporary increase in blood pressure and adverse changes in hemodynamics.
An equally important criterion for the functioning of the respiratory system is the vital capacity of the lungs - the volume of air that a person exhales after a deep breath. A sharp jump in the overall rate of growth and development of the entire respiratory apparatus, including the nasal passages, larynx, trachea, and the general surface of the lungs, occurs during puberty. In adolescents, lung volume is increased 10 times compared to the lungs of a newborn, and in adults - 20 times.
The most intensive growth of the lungs is observed in the period from 12 to 16 years, and in young menthe vital capacity of the lungs is greater than that of girls. In general, adolescents have better cardiorespiratory measures, including natural ventilation, oxygen intake, and circulatory system performance, than younger schoolchildren.
This article discusses all the elements of the human cardiorespiratory system, its features, including adaptation to physical stress and increased endurance. When planning to play sports, it is necessary to take into account all the nuances of the work of your body and correctly distribute the load. The state of the cardiorespiratory system is an important indicator of he alth.
