Internal and external breathing: description, indicators and functions

The adult person makes from fourteen to twenty breaths every minute, and children, depending on age, are able to do up to sixty respiratory movements in the same period of time. It is an unconditioned reflex that helps the body to survive. Its implementation goes beyond the boundaries of our control and understanding. External and internal breathing among themselves have a so-called message. It works on the principle of feedback. If the cells do not have enough oxygen, then the body breathes more quickly, and vice versa.

Definition

Breathing is a complex reflex continuous act. It ensures the constancy of the gas composition of the blood. It consists of three stages or links: external breathing, transport of gases and tissue saturation. Failure can occur at any of the stages. It can lead to hypoxia and even death. External breathing is the first stage in which gas exchange takes place between a person and the environment. First, atmospheric air enters the alveoli. And the next stage diffuses into the blood for transport to the tissues.

The mechanism of getting oxygen into the blood is based on the difference in the partial pressure of the gases. The exchange takes place along the concentration gradient. That is, blood with a high content of carbon dioxide easily takes a sufficient amount of oxygen, and vice versa. Simultaneously, the essence of tissue respiration is as follows: oxygen from the blood enters the cytoplasm of the cell, and then passes through a chain of chemical reactions called the respiratory chain. Eventually, carbon dioxide and other metabolic products enter the peripheral channel.

Composition of air

External respiration has a strong dependence on the composition of atmospheric air. The less oxygen is contained in it, the less breath becomes. Normally, the air composition is approximately the same:

• Nitrogen - 79.03%;
• Oxygen - 20%;
• Carbon dioxide - 0.03%;
• All other gases - 0.04%.

On exhalation, the proportion of parts varies slightly. Carbon dioxide rises to 4%, and oxygen decreases as much.

Structure of the respiratory apparatus

The external respiration system is a series of tubes connected together. Before you get into the alveoli, the air goes a long way to keep warm and clear. It all starts with the nasal passages. They are the first barrier to dust and dirt. Hairs located on the nasal mucosa retain large particles, and closely located vessels warm the air.

Then comes the nasal and oropharynx, after them - the larynx, trachea, the main bronchi. The latter are divided into right and left lobes. They branch out, forming a bronchial tree. The smallest bronchioles on the end have an elastic sac - the alveolus. Despite the fact that the mucous lining all the airways, gas exchange occurs only at the very end. Unused space is called dead. Normally its size reaches up to one hundred and fifty milliliters.

Respiratory cycle

In a healthy person, breathing takes place in three stages: inhalation, exhalation and pause. By the time the whole process takes from two and a half to ten seconds or more. These are very individual parameters. External respiration largely depends on the conditions in which the organism resides and on its state of health. So, there are such concepts as rhythm and frequency of breathing. They are determined by the number of movements of the chest in a minute, their dimensionality. The depth of breathing can be determined by measuring the volume of exhaled air or chest girth during inspiration and exhalation. The process is quite simple.

Inhalation occurs during contraction of the diaphragm and intercostal muscles. Negative pressure, which is created at this moment, as it were, "sucks" atmospheric air into the lungs. In this case, the chest expands. Exhalation is the opposite action: the musculature relaxes, the walls of the alveoli tend to get rid of hyperextension and return to their original state.

Pulmonary ventilation

The study of the function of external respiration helped scientists better understand the mechanism of developing a significant number of diseases. They even identified a separate branch of medicine - pulmonology. There are several criteria for analyzing the work of the respiratory system. The parameters of external respiration are not a rigid quantity. They can vary depending on the constitution of a person, age and state of health:

1. Respiratory volume (TO). This is the amount of air that a person inhales and exhales at rest. Norm - from three hundred to seven hundred milliliters.
2. Reserve volume of inspiration (DOM). It's air that you can add to the lungs. For example, if after a quiet breath, ask a person to take a deep breath.
3. Reserve volume of exhalation (ROVD). This is the amount of air that leaves the lungs, if after a normal exhalation make a deep. Both indicators are about one and a half liters.
4. Residual volume. This is the amount of air that remains in the lungs after a deep exhalation. Its value is from one thousand to one and a half thousand milliliters.
5. The four previous indicators together make up the vital capacity of the lungs. In men it is equal to five liters, in women it is three and a half.

Pulmonary ventilation is the entire volume of air that passes through the lungs in one minute. In an adult healthy person in rest, this figure varies in the region of six to eight liters. The study of the function of external respiration is necessary not only for people who have pathologies, but also for athletes, as well as children (especially preterm neonates). Often, such knowledge is needed in intensive care, when the patient is transferred to mechanical ventilation (artificial ventilation) or removed from it.

Types of normal breathing

The function of external respiration largely depends on the type of process. And also from the constitution and the sex of man. According to the method of chest expansion, two types of breathing can be distinguished:

• Thoracic, during which ribs rise. It predominates in women.
• Abdominal, when the diaphragm is flattened. This kind of breathing is more typical of men.

There is a mixed type when all muscle groups are involved. This indicator is individual. It depends not only on sex, but also on the age of a person, as the mobility of the chest decreases over the years. Affects it and the profession: the harder the work, the more prevails the abdominal type.

Pathological types of breathing

The parameters of external respiration change dramatically in the presence of respiratory failure syndrome. This is not an isolated disease, but only a consequence of the pathology of other organs: the heart, lungs, adrenals, liver or kidneys. Sidromus passes in both acute and chronic form. In addition, it is divided into types:

1. Obstructive. Shortness of breath appears on the breath.
2. Restrictive type. Shortness of breath appears on exhalation.
3. Mixed type. It is usually an end-stage and includes the first two options.

In addition, there are several types of pathological breathing that do not have a binding to a specific disease:

• Cheyne's breath is Stokes. Beginning with superficial, breathing gradually deepens and on the fifth-seventh breath reaches normal parameters. Then again it becomes rare and shallow. In the end, there must be a pause - a few seconds without inhaling. It occurs in newborns, with TBI, intoxication, hydrocephalus.
• Breath of Kussmaul. This is deep, noisy and rare breathing. Occurs in hyperventilation, acidosis, diabetic coma.

Pathology of external respiration

Violation of external respiration occurs both in the normal functioning of the body, and in critical situations:

1. Tachypnoe is a condition where the respiratory rate exceeds twenty times per minute. It happens as a physiological (after a load, in a stuffy room), and pathological (with blood diseases, fever, hysteria).
2. Bradypnoe - a rare breathing. Usually combined with neurological diseases, increased intracranial pressure, brain edema, coma, intoxication.
3. Apnea - absence or stop of breathing. It can be associated with paralysis of the respiratory muscles, poisoning, craniocerebral trauma or brain edema. Also, the symptom of stopping breathing in a dream is highlighted.
4. Dispno - shortness of breath (violation of rhythm, frequency and depth of breathing). It occurs with excessive physical exertion, bronchial asthma, chronic obstructive bronchitis, hypertension.

Where is knowledge needed about the characteristics of external respiration?

Examination of external respiration should be done with a diagnostic purpose to assess the functional state of the entire system. In patients at risk, such as smokers or workers in the harmful industry, they thus show a tendency to occupational diseases. For surgeons and anaesthesiologists, the status of this function is important when preparing a patient for surgery. A dynamic examination of external respiration is conducted to confirm the disability group and assess the overall ability to work. And also for dispensary observation of patients with cardiac or pulmonary chronic diseases.

Types of research

Spirometry is a method of assessing the state of the respiratory system in terms of volume of normal and forced expiration, as well as expiration in 1 second. Sometimes a diagnostic test is performed with a bronchodilator. Its essence lies in the fact that the patient first undergoes a study. Then he receives an inhalation of the medicine, which expands the bronchi. And after 15 minutes, another study is underway. The results are compared. It is concluded that the pathology of the respiratory tract is reversible or irreversible.

Bodipletizmografiya - conducted to assess the overall lung capacity and aerodynamic resistance of the respiratory tract. For this, the patient needs to inhale air. It is in a sealed chamber. In this case, not only the amount of gas is recorded, but also the force with which it is inhaled, as well as the air flow rate.