Mechanism of exhalation (expiration) is ensured through:
· Gravity chest.
· Elasticity of costal cartilages.
· Elasticity of the lungs.
· Pressure of the abdominal organs on the diaphragm.
At rest, exhalation occurs passively.
In forced breathing, expiratory muscles are used: internal intercostal muscles (their direction is from above, back, front, down) and auxiliary expiratory muscles: muscles that flex the spine, abdominal muscles (oblique, rectus, transverse). When the latter contract, the abdominal organs put pressure on the relaxed diaphragm and it protrudes into the chest cavity.
Types of breathing. Depending primarily on which component (raising the ribs or the diaphragm) the chest volume increases, there are 3 types of breathing:
· - thoracic (costal);
· - abdominal;
· - mixed.
To a greater extent, the type of breathing depends on age (the mobility of the chest increases), clothing (tight bodices, swaddling), profession (for people engaged in physical labor, the abdominal type of breathing increases). Abdominal breathing becomes difficult recent months pregnancy, and then breastfeeding is additionally included.
The most effective type of breathing is abdominal:
· - deeper ventilation of the lungs;
· - facilitates the return of venous blood to the heart.
The abdominal type of breathing predominates among manual workers, rock climbers, singers, etc. In a child, after birth, the abdominal type of breathing is first established, and later, by the age of 7, chest breathing.
Pressure in pleural cavity and its changes during breathing.
The lungs are covered with visceral pleura, and the film of the chest cavity is covered with parietal pleura. Between them there is serous fluid. They fit tightly to each other (gap 5-10 microns) and slide relative to each other. This sliding is necessary so that the lungs can follow the complex changes of the chest without deforming. With inflammation (pleurisy, adhesions), ventilation of the corresponding areas of the lungs decreases.
If you insert a needle into the pleural cavity and connect it to a water pressure gauge, you will find that the pressure in it is:
· when inhaling - by 6-8 cm H 2 O
· when exhaling - 3-5 cm H 2 O below atmospheric.
This difference between intrapleural and atmospheric pressure is usually called pleural cavity pressure.
Negative pressure in the pleural cavity is caused by elastic traction of the lungs, i.e. tendency of the lungs to collapse.
When inhaling, an increase in the thoracic cavity leads to an increase in negative pressure in the pleural cavity, i.e. transpulmonary pressure increases, leading to expansion of the lungs (demonstration using the Donders apparatus).
When the inspiratory muscles relax, transpulmonary pressure decreases and the lungs collapse due to elasticity.
If a small amount of air is introduced into the pleural cavity, it will dissolve, since in the blood of small veins of the pulmonary circulation the tension of dissolved gases is less than in the atmosphere.
The accumulation of fluid in the pleural cavity is prevented by the lower oncotic pressure of pleural fluid (less proteins) than in plasma. A decrease in hydrostatic pressure in the pulmonary circulation is also important.
The change in pressure in the pleural cavity can be measured directly (but lung tissue may be damaged). Therefore, it is better to measure it by inserting a 10 cm long balloon into the esophagus (into the thoracic part). The walls of the esophagus are very pliable.
Elastic traction of the lungs is caused by 3 factors:
1. Surface tension of the film of liquid covering the inner surface of the alveoli.
2. The elasticity of the tissue of the walls of the alveoli (contain elastic fibers).
3. Tone of the bronchial muscles.
At any interface between air and liquid, intermolecular cohesion forces act, tending to reduce the size of this surface (surface tension forces). Under the influence of these forces, the alveoli tend to contract. Surface tension forces create 2/3 of the elastic traction of the lungs. The surface tension of the alveoli is 10 times less than theoretically calculated for the corresponding water surface.
If the inner surface of the alveoli were covered aqueous solution, then the surface tension should have been 5-8 times greater. Under these conditions there would be collapse of the alveoli (atelectasis). But this doesn't happen.
This means that in the alveolar fluid on the inner surface of the alveoli there are substances that reduce surface tension, i.e. surfactants. Their molecules are strongly attracted to each other, but have a weak interaction with liquid, as a result of which they collect on the surface and thereby reduce surface tension.
Such substances are called superficial active substances(surfactants), whose role in in this case perform so-called surfactants. They are lipids and proteins. They are formed by special cells of the alveoli - type II pneumocytes. The lining has a thickness of 20-100 nm. But lecithin derivatives have the greatest surface activity of the components of this mixture.
When the size of the alveoli decreases. surfactant molecules come closer together, their density per unit surface area is greater and surface tension decreases - the alveolus does not collapse.
As the alveoli enlarge (expand) their surface tension increases, as the density of surfactant per unit surface area decreases. This enhances the elastic traction of the lungs.
In the process of breathing increases respiratory muscles is spent on overcoming not only the elastic resistance of the lungs and chest tissues, but also on overcoming the inelastic resistance to gas flow in the airways, which depends on their lumen.
Impaired formation of surfactants leads to the collapse of a large number of alveoli - atelectasis - lack of ventilation of large areas of the lungs.
In newborns, surfactants are necessary for the expansion of the lungs during the first respiratory movements.
Mechanism external respiration. External respiration is the exchange of gases between the body and the surrounding atmospheric air. External respiration is a rhythmic process, the frequency of which in a healthy adult is 16-20 cycles per minute. The main task of external respiration is to maintain a constant composition of alveolar air - 14% oxygen and 5% carbon dioxide.
Despite the fact that the lungs are not fused to the chest wall, they repeat its movements. This is explained by the fact that there is a closed pleural fissure between them. From the inside, the wall of the chest cavity is covered with the parietal layer of the pleura, and the lungs with its visceral layer. In the interpleural fissure there is a small amount serous fluid. When you inhale, the volume of the chest cavity increases. And since the pleural is isolated from the atmosphere, the pressure in it decreases. The lungs expand, the pressure in the alveoli becomes lower than atmospheric pressure. Air enters the alveoli through the trachea and bronchi. During exhalation, the volume of the chest decreases. The pressure in the pleural fissure increases, air leaves the alveoli. Movements or excursions of the lungs are explained by fluctuations in negative interpleural pressure. The pressure in the pleural cavity during the respiratory pause is 3-4 mm Hg below atmospheric pressure, i.e. negative. This is caused by the elastic traction of the lungs to the root, creating some vacuum in the pleural cavity. This is the force with which the lungs tend to contract towards the roots, counteracting atmospheric pressure. It is due to the elasticity of the lung tissue, which contains many elastic fibers. In addition, elastic traction increases the surface tension of the alveoli. During inhalation, the pressure in the pleural cavity decreases further due to an increase in the volume of the chest, which means that the negative pressure increases. The amount of negative pressure in the pleural cavity is equal to: at the end of maximum exhalation - 1-2 mm Hg. Art., by the end of a quiet exhalation - 2-3 mm Hg. Art., by the end of a quiet inspiration -5-7 mm Hg. Art., by the end of maximum inspiration - 15-20 mm Hg. Art. During exhalation, the volume of the chest decreases, at the same time the pressure in the pleural cavity increases, and depending on the intensity of exhalation, it can become positive.
Pneumothorax. In case of damage to the chest, air enters the pleural cavity. In this case, the lungs are compressed under the pressure of the incoming air due to the elasticity of the lung tissue and the surface tension of the alveoli. As a result, during breathing movements the lungs are not able to follow the chest, and gas exchange in them decreases or completely stops. With unilateral pneumothorax, breathing with only one lung on the uninjured side can meet the respiratory need in the absence of physical activity. Bilateral pneumothorax makes natural breathing impossible; in this case, the only way to save life is artificial respiration.
Dynamic stereotype
A particularly complex type of work of the central nervous system is stereotypical conditioned reflex activity, or, as I. P. Pavlov called it, a dynamic stereotype.
The dynamic stereotype, or systematicity in the work of the cortex, is as follows. In the process of life (nursery, kindergarten, school, work), a person is affected in a certain order by various conditioned and unconditioned stimuli, so the individual creates a certain stereotype of cortical reactions to the entire system of stimuli. The conditioned signal is perceived not as an isolated stimulus, but as an element of a certain system of signals, which is in connection with the previous and subsequent stimuli. Therefore, work on new system(for example, the admission of a young
person to university) leads to the breaking of old and development of new stereotypes of reactions depending on the conditions. The development of new dynamic stereotypes occurs more quickly in young organisms. In children under three years of age they are most durable. Therefore, at this age, as well as in older people, breaking existing stereotypes sometimes leads to psychological discomfort. This can have a detrimental effect on health, especially for older people (for example, sudden dismissal due to staff reduction).
RESPIRATION is a set of processes that ensure the body consumes oxygen (O2) and releases carbon dioxide (CO2)
STEPS OF BREATHING:
1. External respiration or ventilation of the lungs - exchange of gases between atmospheric and alveolar air
2. Exchange of gases between the alveolar air and the blood of the capillaries of the pulmonary circulation
3. Transport of gases by blood (O 2 and CO 2)
4. Exchange of gases in tissues between blood capillaries great circle blood circulation and tissue cells
5. Tissue, or internal, respiration - the process of tissue absorption of O 2 and release of CO 2 (redox reactions in mitochondria with the formation of ATP)
RESPIRATORY SYSTEM
A set of organs that supply the body with oxygen, remove carbon dioxide and release energy necessary for all forms of life.
FUNCTIONS OF THE RESPIRATORY SYSTEM:
Ø Providing the body with oxygen and using it in redox processes
Ø Formation and release of excess carbon dioxide from the body
Ø Oxidation (decomposition) of organic compounds with the release of energy
Ø Release of volatile metabolic products (water vapor (500 ml per day), alcohol, ammonia, etc.)
Processes underlying the execution of functions:
a) ventilation (airing)
b) gas exchange
STRUCTURE OF THE RESPIRATORY SYSTEM
Rice. 12.1. Structure respiratory system
1 – Nasal passage
2 – Turbinate
3 – Frontal sinus
4 – Sphenoid sinus
5 – Throat
6 – Larynx
7 – Trachea
8 – Left bronchus
9 – Right bronchus
10 – Left bronchial tree
11 – Right bronchial tree
12 – Left lung
13 – Right lung
14 – Aperture
16 – Esophagus
17 – Ribs
18 – Sternum
19 – Clavicle
the organ of smell, as well as the external opening of the respiratory tract: serves to warm and purify the inhaled air
NASAL CAVITY
Primary department respiratory tract and at the same time the organ of smell. Stretches from the nostrils to the pharynx, divided by a septum into two halves, which are in front through nostrils communicate with the atmosphere, and behind with the help joan- with nasopharynx
Rice. 12.2. Structure of the nasal cavity
Larynx
a piece of breathing tube that connects the pharynx to the trachea. Located at the level of IV-VI cervical vertebrae. It is an entrance hole that protects the lungs. Located in the larynx vocal cords. Behind the larynx is the pharynx, with which it communicates through its superior opening. Below the larynx passes into the trachea
Rice. 12.3. Structure of the larynx
Glottis- the space between the right and left vocal folds. When the position of the cartilage changes, under the action of the muscles of the larynx, the width of the glottis and the tension of the vocal cords can change. Exhaled air vibrates the vocal cords ® sounds are produced
Trachea
a tube that communicates with the larynx at the top and ends with a division at the bottom ( bifurcation ) into two main bronchi
Rice. 12.4. Main airways
Inhaled air passes through the larynx into the trachea. From here it is divided into two streams, each of which goes to its own lung through a branched system of bronchi
BRONCHI
tubular formations representing the branches of the trachea. They depart from the trachea almost at a right angle and go to the gates of the lungs
Right bronchus wider but shorter left and is like a continuation of the trachea
The bronchi are similar in structure to the trachea; they are very flexible due to cartilaginous rings in the walls and are lined respiratory epithelium. The connective tissue base is rich in elastic fibers that can change the diameter of the bronchus
Main bronchi(first order) are divided into equity (second order): three in the right lung and two in the left - each goes to its own lobe. Then they are divided into smaller ones, going into their own segments - segmental (third order), which continue to divide, forming "bronchial tree" lung
BRONCHIAL TREE– the bronchial system, through which air from the trachea enters the lungs; includes main, lobar, segmental, subsegmental (9-10 generations) bronchi, as well as bronchioles (lobular, terminal and respiratory)
Within the bronchopulmonary segments, the bronchi divide successively up to 23 times until they end in a dead end of alveolar sacs
Bronchioles(diameter of the respiratory tract less than 1 mm) divide until they form end (terminal) bronchioles, which are divided into the thinnest short airways - respiratory bronchioles, turning into alveolar ducts, on the walls of which there are bubbles - alveoli (air sacs). The main part of the alveoli is concentrated in clusters at the ends alveolar ducts formed during the division of respiratory bronchioles
Rice. 12.5. Lower respiratory tract
Rice. 12.6. Airway, gas exchange area and their volumes after quiet exhalation
Functions of the airways:
1. Gas exchange - delivery atmospheric air V gas exchange area and conduction of the gas mixture from the lungs into the atmosphere
2. Non-gas exchange:
§ Air purification from dust and microorganisms. Protective breathing reflexes (coughing, sneezing).
§ Humidification of inhaled air
§ Warming of inhaled air (at the level of the 10th generation up to 37 0 C
§ Reception (perception) of olfactory, temperature, mechanical stimuli
§ Participation in the processes of thermoregulation of the body (heat production, heat evaporation, convection)
§ Are peripheral apparatus sound generation
Acinus
a structural unit of the lung (up to 300 thousand), in which gas exchange occurs between the blood located in the capillaries of the lung and the air filling the pulmonary alveoli. It is a complex from the beginning of the respiratory bronchiole, resembling a bunch of grapes in appearance
The acini includes 15-20 alveoli, into the pulmonary lobule - 12-18 acini. Lobes of the lung are made up of lobules
Rice. 12.7. Pulmonary acinus
Alveoli(in the lungs of an adult there are 300 million, their total surface area is 140 m2) - open vesicles with very thin walls, the inner surface of which is lined with single-layer squamous epithelium lying on the main membrane, to which the entwining alveoli are adjacent blood capillaries, forming, together with epithelial cells, a barrier between blood and air (air-blood barrier) 0.5 microns thick, which does not interfere with the exchange of gases and the release of water vapor
Found in the alveoli:
§ macrophages(protective cells) that absorb foreign particles entering the respiratory tract
§ pneumocytes- cells that secrete surfactant
Rice. 12.8. Ultrastructure of the alveoli
SURFACTANT– a pulmonary surfactant containing phospholipids (in particular lecithin), triglycerides, cholesterol, proteins and carbohydrates and forming a 50 nm thick layer inside the alveoli, alveolar ducts, sacs, bronchioles
Surfactant value:
§ Reduces the surface tension of the fluid covering the alveoli (almost 10 times) ® makes inhalation easier and prevents atelectasis (sticking together) of the alveoli during exhalation.
§ Facilitates the diffusion of oxygen from the alveoli into the blood due to the good solubility of oxygen in it.
§ Performs a protective role: 1) has bacteriostatic activity; 2) protects the walls of the alveoli from the damaging effects of oxidizing agents and peroxides; 3) provides reverse transport of dust and microbes through the airway; 4) reduces the permeability of the pulmonary membrane, which prevents the development of pulmonary edema due to a decrease in the exudation of fluid from the blood into the alveoli
LUNGS
The right and left lung are two separate objects located in the chest cavity on either side of the heart; covered with a serous membrane - pleura, which forms around them two closed pleural sac. They have an irregular cone shape with the base facing the diaphragm and the apex protruding 2-3 cm above the collarbone in the neck area
Rice. 12.10. Segmental structure of the lungs.
1 – apical segment; 2 – posterior segment; 3 – anterior segment; 4 – lateral segment ( right lung) and superior lingular segment (left lung); 5 – medial segment (right lung) and lower lingular segment (left lung); 6 – apical segment of the lower lobe; 7 – basal medial segment; 8 – basal anterior segment; 9 – basal lateral segment; 10 – basal posterior segment
ELASTICITY OF THE LUNGS
the ability to respond to load by increasing voltage, which includes:
§ elasticity– the ability to restore its shape and volume after the cessation of external forces causing deformation
§ rigidity– the ability to resist further deformation when elasticity is exceeded
Reasons elastic properties lungs:
§ elastic fiber tension lung parenchyma
§ surface tension fluid lining the alveoli - created by surfactant
§ blood filling of the lungs (the higher the blood filling, the less elasticity
Extensibility– the inverse property of elasticity is associated with the presence of elastic and collagen fibers that form a spiral network around the alveoli
Plastic– property opposite to rigidity
FUNCTIONS OF THE LUNGS
Gas exchange– enrichment of blood with oxygen used by body tissues and removal of carbon dioxide from it: achieved through pulmonary circulation. Blood from the body's organs returns to right side hearts and pulmonary arteries goes to the lungs
Non-gas exchange:
Ø Z protective – formation of antibodies, phagocytosis by alveolar phagocytes, production of lysozyme, interferon, lactoferrin, immunoglobulins; Microbes, aggregates of fat cells, and thromboemboli are retained and destroyed in the capillaries
Ø Participation in thermoregulation processes
Ø Participation in allocation processes – removal of CO 2, water (about 0.5 l/day) and some volatile substances: ethanol, ether, nitrous oxide, acetone, ethyl mercaptan
Ø Inactivation of biologically active substances – more than 80% of bradykinin introduced into the pulmonary bloodstream is destroyed during a single passage of blood through the lung, angiotensin I is converted to angiotensin II under the influence of angiotensinase; 90-95% of prostaglandins of groups E and P are inactivated
Ø Participation in the production of biologically active substances –heparin, thromboxane B 2, prostaglandins, thromboplastin, blood coagulation factors VII and VIII, histamine, serotonin
Ø They serve as an air reservoir for voice production
EXTERNAL BREATHING
The process of ventilation of the lungs, providing gas exchange between the body and the environment. It is carried out due to the presence of the respiratory center, its afferent and efferent systems, and respiratory muscles. It is assessed by the ratio of alveolar ventilation to minute volume. To characterize external respiration, static and dynamic indicators of external respiration are used
Respiratory cycle– rhythmically repeating change in the state of the respiratory center and executive respiratory organs
Rice. 12.11. Respiratory muscles
Diaphragm- a flat muscle that separates the chest cavity from the abdominal cavity. It forms two domes, left and right, with their bulges pointing upward, between which there is a small depression for the heart. There are several holes in it, through which very important structures body. By contracting, it increases the volume of the chest cavity and provides air flow into the lungs
Rice. 12.12. Position of the diaphragm during inhalation and exhalation
pressure in the pleural cavity
physical quantity, characterizing the state of the contents of the pleural cavity. This is the amount by which the pressure in the pleural cavity is lower than atmospheric pressure ( negative pressure); with quiet breathing it is equal to 4 mmHg. Art. at end expiration and 8 mmHg. Art. at the end of the inhalation. Created by surface tension forces and elastic traction of the lung
Rice. 12.13. Pressure changes during inhalation and exhalation
INHALE(inspiration) is the physiological act of filling the lungs with atmospheric air. It is carried out due to the active activity of the respiratory center and respiratory muscles, which increases the volume of the chest, resulting in a decrease in pressure in the pleural cavity and alveoli, which leads to the entry of air environment into the trachea, bronchi and respiratory zones of the lung. Occurs without the active participation of the lungs, since there are no contractile elements in them
EXHALATION(expiration) is the physiological act of removing from the lung part of the air that takes part in gas exchange. First, the air of the anatomical and physiological dead space, which differs little from atmospheric air, is removed, then the alveolar air, enriched in CO 2 and poor in O 2 as a result of gas exchange. Under resting conditions the process is passive. It is carried out without the expenditure of muscle energy, due to the elastic traction of the lung, chest, gravitational forces and relaxation of the respiratory muscles
With forced breathing, the depth of exhalation increases with the help of abdominal and internal intercostal muscles. Abdominal muscles squeeze abdominal cavity in front and enhance the rise of the diaphragm. The internal intercostal muscles move the ribs down and thereby reduce the cross-section of the thoracic cavity, and therefore its volume
a physical quantity characterizing the state of the contents of the pleural cavity. This is the amount by which the pressure in the pleural cavity is lower than atmospheric ( negative pressure); with quiet breathing it is equal to 4 mmHg. Art. at end expiration and 8 mmHg. Art. at the end of the inhalation. Created by surface tension forces and elastic traction of the lung
Rice. 12.13. Pressure changes during inhalation and exhalation
INHALE(inspiration) is the physiological act of filling the lungs with atmospheric air. It is carried out due to the active activity of the respiratory center and respiratory muscles, which increases the volume of the chest, resulting in a decrease in pressure in the pleural cavity and alveoli, which leads to the entry of environmental air into the trachea, bronchi and respiratory zones of the lung. Occurs without the active participation of the lungs, since there are no contractile elements in them
EXHALATION(expiration) is the physiological act of removing from the lung part of the air that takes part in gas exchange. First, the air of the anatomical and physiological dead space, which differs little from atmospheric air, is removed, then the alveolar air, enriched in CO 2 and poor in O 2 as a result of gas exchange. Under resting conditions the process is passive. It is carried out without the expenditure of muscle energy, due to the elastic traction of the lung, chest, gravitational forces and relaxation of the respiratory muscles
With forced breathing, the depth of exhalation increases with the help of abdominal and internal intercostal muscles. The abdominal muscles compress the abdominal cavity from the front and increase the rise of the diaphragm. The internal intercostal muscles move the ribs down and thereby reduce the cross-section of the thoracic cavity, and therefore its volume
values characterizing potential breathing capabilities, depending on anthropometric data and characteristics of the functional volumes of the lung
|
PULMONARY VOLUME |
CHARACTERISTIC |
Volume in an adult, ml |
|
Tidal volume (TO) |
the volume of air that a person can inhale (exhale) during quiet breathing | |
|
Inspiratory reserve volume (IR) Vd ) |
the amount of air that can be additionally introduced during maximum inspiration | |
|
Expiratory reserve volume (ERV) Vyd ) |
the volume of air that a person can exhale additionally after a quiet exhalation | |
|
Residual volume (VR) |
volume of air that remains in the lungs after maximum exhalation | |
|
Vital capacity of the lungs (VC) |
The maximum volume of air that can be exhaled after a maximum inhalation. Depends on total lung capacity, strength of respiratory muscles, chest and lungs (YEL) = RO in + DO + RO in |
For men – 3500-5000 For women – 3000-3500 |
|
Total lung capacity (TLC) |
The greatest amount of air that completely fills the lungs. Characterizes the degree of anatomical development of the organ (VEL) = vital capacity + OO | |
|
Functional residual capacity (FRC) |
The amount of air remaining in the lungs after a quiet exhalation (FOE) = RO Ext + OO |
Static breathing parameters are determined by spirometry.
Spirometry– determination of static indicators of respiration (volumes - except residual; capacities - except FRC and TEL) by exhaling air through a device that records its quantity (volume). In modern dry vane spirometers, air rotates an air turbine connected to a needle
Rice. 12.14. Lung volumes and capacities
Pleura, pleura, which is the serous membrane of the lung, is divided into visceral (pulmonary) pleura and parietal (parietal). Each lung is covered with pleura (pulmonary), which along the surface of the root passes into the parietal pleura, lining the walls of the chest cavity adjacent to the lung and bordering the mediastinum on the sides.
The pleural cavity (cavitas pleuralis) is located between the parietal and visceral pleura in the form of a narrow slit; it contains a small amount of serous fluid that moisturizes the layers of the pleura, helping to reduce the friction of the leaves of the visceral and parietal pleura against each other during respiratory movements of the lungs.
The pressure in the pleural cavity is below atmospheric pressure, which is defined as negative pressure. It is caused by elastic traction of the lungs, i.e. the constant desire of the lungs to reduce their volume. The pressure in the pleural cavity is lower than the alveolar one by the amount created by the elastic traction of the lungs: Ppl = Ralv - Re.t.l.. elastic traction of the lungs is caused by three factors:
Surface tension of the film of liquid covering the inner surface of the alveoli - surfactant.
2) The elasticity of the tissue of the walls of the alveoli, which have elastic fibers in the wall.
3) Tone of the bronchial muscles
Accumulation of air or gases in the pleural cavity.
Spontaneous pneumothorax occurs when the pulmonary alveoli rupture (with tuberculosis, emphysema); traumatic - when the chest is damaged.
Tension pneumothorax occurs when air enters the pleural cavity and it is impossible to remove it independently. This leads to an increase in pressure, compression of mediastinal structures, disruption of venous inflow, shock and possible death.
What are the pulmonary volumes and capacities, what methods do you know for determining them?
During the process of pulmonary ventilation, the gas composition of the alveolar air is continuously updated. The amount of pulmonary ventilation is determined by the depth of breathing, or tidal volume, and the frequency of respiratory movements. During breathing movements, a person’s lungs are filled with inhaled air, the volume of which is part of the total volume of the lungs. For quantitative description pulmonary ventilation, the total lung capacity was divided into several components or volumes. In this case, the pulmonary capacity is the sum of two or more volumes.
Lung volumes are divided into static and dynamic. Static pulmonary volumes are measured during completed respiratory movements without limiting their speed. Dynamic pulmonary volumes are measured during respiratory movements with a time limit for their implementation.
Lung volumes. The volume of air in the lungs and respiratory tract depends on the following indicators: 1) anthropometric individual characteristics of a person and the respiratory system; 2) properties of lung tissue; 3) surface tension of the alveoli; 4) the force developed by the respiratory muscles.
Lung capacity. Vital capacity of the lungs (VC) includes tidal volume, inspiratory reserve volume, and expiratory reserve volume. In middle-aged men, vital capacity varies between 3.5-5.0 liters and more. For women, lower values are typical (3.0-4.0 l). Depending on the methodology for measuring vital capacity, a distinction is made between inhalation vital capacity, when after a complete exhalation a maximum deep breath is taken, and exhalation vital capacity, when after a full inhalation a maximum exhalation is made.
Methods for measuring lung volumes
1. Spirometry - measurement of lung volumes. Allows you to determine vital capacity, DO, ROvd, ROvyd.
2. Spirography - registration of lung volumes. Allows you to document vital capacity, BC, ROvd, ROvd, as well as respiratory rate.
Determination of residual volume
Using a closed-loop spirograph using helium /according to the degree of helium dilution/.
General plethysmography of the body /bodyplethysmography/.
What is pulmonary and alveolar ventilation? What are the methods for determining MOD?
What is dead space and what is its significance?
When does maximum ventilation occur? What is breathing reserve, how to calculate it?
What is the name of the structural and functional unit of the lungs?
What is the composition of atmospheric, exhaled and alveolar air? Definition and comparison.
What patterns ensure the diffusion of gases from one medium to another?
How does gas exchange occur in the lungs? What is the partial pressure of gases in the alveolar air and the tension of gases in the blood?
How is oxygen transported by blood? What is the oxygen capacity of the blood, what is it normally equal to?
How is carbon dioxide transported in the blood? What role does carbonic anhydrase play in this process?
Where is the respiratory center located? What structures does it consist of?
What does it include functional system, ensuring the constancy of the blood gas composition?
What is artificial ventilation?
In what cases is artificial ventilation used?
What methods are used for artificial ventilation lungs?
What is artificial respiration?
What methods are used for artificial respiration?
What are the general characteristics of body fluids? What are intracellular and extracellular fluids?
What is included in the blood system?
What functions does blood perform?
What organs perform the function of blood depot, what is the significance of blood depot?
What is the composition of blood?
What is plasma and what is its composition?
