To use presentation previews, create an account for yourself ( account) Google and log in: https://accounts.google.com
Slide captions:
OGE assignments on the topic “ Respiratory system».
1). What disease can a doctor detect using fluorographic examination? chest person? 1) tuberculosis 2) hypertension 3) stomach ulcer 4) gastritis
2). Where in the human body does carbon dioxide form? 1) muscle fibers 2) glottis 3) mature erythrocytes 4) intercellular substance
3). Which organ of the respiratory system consists of cartilaginous half-rings? 1) lung 2) pharynx 3) larynx 4) trachea
4). What are the consequences of smoking tobacco? 1) to the death of cells of the ciliated epithelium of the airways 2) to the expansion of small bronchi and blood flow 3) to rarer and deeper breathing 4) to the expansion of blood vessels
5). In a smoker, gas exchange in the lungs is less effective, because he 1) develops hypertension 2) activity worsens nerve centers 3) the walls of the alveoli become covered with foreign substances 4) the death of mucosal cells occurs respiratory tract
6). Which human organ system is shown in the picture? 1) circulatory 2) excretory 3) digestive 4) respiratory
7). The likelihood of tuberculosis in humans increases with 1) excess weight 2) contact with animals 3) increased illumination 4) living in a room with high humidity
8). What are the consequences of smoking tobacco? 1) to the expansion of blood vessels 2) to the death of cells of the ciliated epithelium of the airways 3) to the expansion of small bronchi 4) to less frequent breathing
9). What disease is transmitted by airborne droplets? 1) malaria 2) anemia 3) influenza 4) gastritis
10). Gas exchange in humans during breathing occurs in 1) pulmonary alveoli 2) nasal cavity 3) larynx and trachea 4) bronchi
11. What helps to increase the vital capacity of the lungs? 1) extensibility of lung tissue 2) activation humoral regulation 3) development of intercostal muscles and diaphragm 4) increase in blood flow speed
12. Are the judgments about respiratory movements in the human body correct? A. B calm state In a person, inhalation is carried out due to the contraction of the intercostal muscles and the muscles of the diaphragm. B. When exhaling, under the influence of their own gravity, the ribs lower, the muscles of the diaphragm relax. 1) only A is true 2) only B is true 3) both judgments are correct 4) both judgments are incorrect
13. In which of the following parts of the respiratory system does gas exchange between blood and air occur? 1) alveoli 2) bronchi 3) trachea 4) nasopharynx
14. An increase in the concentration of which substance in the blood causes excitation of the respiratory center? 1) oxygen 2) nitrogen 3) carbon dioxide 4) glucose
15. Why is drinking alcohol and smoking dangerous for the health of not only the person himself, but also his offspring? 1) This contributes to the development of hypertension. 2) It increases the risk oncological diseases lungs. 3) This destroys the mucous membrane of the digestive canal. 4) This causes disruption of embryonic development.
16. What change occurs to the diaphragm during inhalation? 1) contracts and becomes convex 2) contracts and becomes flat 3) relaxes and bends towards the chest cavity 4) bends towards the abdominal cavity
17. Where should one begin to provide assistance to a victim in unconscious? 1) unfasten the tight collar and loosen the belt 2) check for a pulse carotid artery 3)proceed to cardiopulmonary resuscitation 4) bring a cotton swab with ammonia to your nose
18. Oxygen enters the intercellular space from a blood vessel because the pressure in it is 1) lower than in the vessel 2) higher than in the vessel 3) equal to the pressure in the vessel 4) constantly changing
20. Are the judgments about the exchange of gases in the lungs in humans correct? A. The essence of the penetration of oxygen from the alveoli into the blood, and carbon dioxide from the blood into the alveoli of the lungs, is that the molecules of any gas, if their concentration is high, tend to penetrate through the membranes permeable to them to where there are few of them. B. Diffusion of gases (O 2 and CO 2) continues until their concentration on both sides of the permeable shell becomes the same. 1) only A is true 2) only B is true 3) both judgments are correct 4) both judgments are incorrect
21. Which layer of cells in the nasal cavity helps purify the air a person inhales? 1) ciliated epithelium 2) muscle tissue 3) blood 4) cartilage tissue
22. What needs to be done to free the victim’s airways from water? 1) give the victim a sitting position and place a cushion under his head 2) place the victim on the rescuer’s knee face down and press on the back 3) place it on the chest pressure bandage and raise the victim’s legs 4) place it on the victim’s chest warm heating pad and wrap him in a blanket
23. The respiratory system has a branched structure: 1) trachea 2) larynx 3) bronchus 4) alveolus
24. If stove heating is not properly organized, the main danger is 1) carbon dioxide 2) nitrogen 3) carbon monoxide 4) water vapor
25. Who and why needs to wear a gauze mask covering the mouth and nose? 1) a healthy person in public places, so as not to become infected from others 2) a healthy person all the time, so as not to become infected with airborne viruses 3) a sick person in public places, so as not to infect others 4) a sick person all the time, so as not to increase the number airborne viruses
26. In winter, the air temperature in the respiratory tract is 1) equal to the temperature of inhaled air 2) significantly higher than body temperature 3) significantly less than body temperature 4) reaches body temperature
27. Which letter in the picture indicates the organ in which sounds are produced? 1)A 2)B 3)C 4)D
28. In what order should you do it? artificial respiration and cardiac massage? 1) one exhalation - four pressings on the sternum 2) one pressing on the sternum - four exhalations 3) two exhalations - five pressings on the sternum 4) three exhalations - three pressings on the sternum
29. Oxygen is used by the human body in the process of 1) conversion of glucose into glycogen 2) oxidation of minerals 3) biosynthesis of proteins, fats and carbohydrates 4) oxidation organic matter with energy release
30. Gas exchange between blood and atmospheric air occurs in 1) muscle cells 2) pulmonary vesicles 3) arteries 4) veins
31. In the alveoli of the human lungs, 1) oxidation of organic substances occurs, 2) synthesis of organic substances, 3) diffusion of oxygen into the blood, 4) purification of dust from the air.
32. When the lungs are injured, first of all it is necessary to 1) perform artificial respiration 2) tightly fix the chest while exhaling 3) carry out indirect massage heart 4) place the victim on his stomach
33. What shaped elements blood carry oxygen from the lungs to the tissues? 1) phagocytes 2) erythrocytes 3) lymphocytes 4) platelets
34. Gas exchange in arteries and veins does not occur due to the fact that 1) they are lined with epithelial tissue 2) the blood pressure in them is insufficient 3) blood flows at high speed 4) they have thick and multi-layered walls
35. Oxygen comes from the alveoli of the lungs into the blood because its pressure in them is 1) equal to its pressure in the blood 2) less than its pressure in the blood 3) greater than its pressure in the blood 4) constantly changing
36. Human breathing is regulated by 1) the medulla oblongata 2) the spinal cord 3) the cerebellum 4) the midbrain
37. Presence of air in pleural cavity is a consequence of 1) damage to the membranes 2) professional sports 3) many years of smoking 4) damage to the respiratory center
38. In which cavity of the human body is the pulmonary trunk located? 1) pelvic 2) skull 3) abdominal 4) thoracic
39. In case of penetrating injury to the lungs, first of all it is necessary to 1) perform artificial respiration 2) tightly fix the chest as you exhale 3) perform an indirect cardiac massage 4) place the victim on his stomach
40. What letter in the picture represents the lung? 1)A 2)B 3)C 4)D
41. In which part of the brain are the centers that provide protective reactions of coughing and sneezing located? 1) anterior 2) oblong 3) intermediate 4) middle
42. Diffusion of gases in the human body occurs in 1) the alveolus 2) the nasal mucosa 3) the wall of the bronchi 4) the wall of the trachea
43. Human breathing is pulmonary. Normally, inhaled air passes through the nasal cavity. There, the air is warmed by the blood-carrying nasal passages (A) located in the walls of the nasal passages. Also located in the nasal cavity are (B), which trap large dust particles. The air then enters (B) through the nasopharynx, from where it enters the trachea. The ciliated epithelium of the trachea contains constantly oscillating (G), which expel dust particles from the lungs that are not filtered in the nasal cavity. From the trachea, air enters (D) through the bronchi, where gas exchange occurs. 1) villus 2) hair 3) capillary 4) arteriole 5) pharynx 6) larynx 7) alveolus 8) pulmonary sac
44. Establish the order in which air passes through the respiratory system of a chewing person when inhaling. Write down the corresponding sequence of numbers in your answer. 1) larynx 2) trachea 3) lung alveoli 4) nasal cavity 5) nasopharynx 6) bronchi
45. What happens to the air in the human nasal cavity? Choose three correct answers out of six and write down the numbers under which they are indicated. 1) oxidizes organic substances 2) combines with hemoglobin 3) is filtered 4) warmed or cooled 5) moisturized 6) penetrates the capillaries of the mucous membrane
46. What is vital capacity lungs (VC) and what does it consist of?
Tip 1. Divide questions about breathing into different blocks
Very difficult for students Unified State Exam in Biology are questions about breathing. Many cannot separate at all:
gas exchange
breathing mechanism
transport of gases by blood.
Even the process gas exchange Many people have the wrong idea, thinking that it only goes to the lungs. Gas exchange also occurs in tissues. Understanding the topic becomes difficult different approach to it in textbooks.
Tip 2. Be aware of the general structure of breathing as a process
I always remind you that breath how the process is divided into external and internal, as well as the transport of gases by blood. I explain external breathing using the mechanisms of inhalation and exhalation as an example. I also look at gas exchange in the lungs here.
Tip 3: Mention diffusion often.
Often students do not indicate that gas exchange is based on diffusion. And this is very important. Wherein great importance has where a certain gas diffuses. If gas exchange occurs in the lungs, we must say that oxygen from the cavity of the alveoli goes into the capillaries, and carbon dioxide in the opposite direction. If gas exchange occurs in tissues, do not forget about the intermediary between all cells and capillaries: tissue fluid. And here we also need to mention diffusion.
Tip 4. Be prepared for unexpected wording
Compiled by Unified State Exam in Biology They may ask: “How do breathing movements proceed under conditions of calm inhalation and exhalation?” (I quote the text of the question). The question is formulated cunningly, as if the student is being pushed to the idea that during physical activity breathing is completely different. However, the breathing mechanism itself does not change, just more muscles are involved. It seems to me that the compilers simply want to confuse the student with this “free breath”. Imagine that such words are not in the question; in fact, the student was asked about how inhalation and exhalation occur. This is what should be answered.
Tip 5: Mention the intercostal muscles
I always tell students that general formulations must be used in the Unified State Examination. But this needs to be done subtly, which is not always possible. In FIPI's response we do not see a word about external intercostal muscles, although they are meant when speaking about the contraction of the intercostal muscles during inhalation. Of course, you can write in detail: the external intercostal muscles contract when you inhale, the internal ones contract when you exhale. However, it is better to mention that when you exhale, the external intercostal muscles also relax. It is these that the compilers of FIPI mean by “intercostal muscles.”
Tip 6. Remember the value of the diaphragm and chest volume
The compilers of the Unified State Examination standardly mention contraction of the diaphragm. In the very first point, for which the student will receive 1 point, the compilers write about increasing the volume of the chest - this is a very important idea. The contraction of the diaphragm helps increase the volume of the chest. But not only that. In my classes, I always say that the contraction of the external intercostal muscles also contributes to lifting. It is they who raise the chest, in which there is more room for inhalation.
Tip 7. Comment on the elasticity of the lungs and pressure in the pleural cavity
How do you get a second point for this question? We need to write about what lungs stretch thanks to their elasticity. We have another related FIPI question about the structure and functions of the lungs. In my classes I talk about the fact that the alveoli of the lungs consist not only of epithelial tissue, they also have stretchable elastic fibers at the base.
Moreover, it is known that the pressure inside the pleural cavity is negative. It turns out that the lungs stretch not only due to their elasticity - this is also facilitated by low pressure in the pleural cavity.
After stretching the lungs, the pressure in them becomes lower, even less than atmospheric. This is easy to understand: the contraction of the diaphragm and muscles led to the fact that more free space appeared in the lungs. That's why the pressure dropped sharply. All this occurs during inhalation and contributes to it.
Tip 8. Understand the importance of negative pressure in the pleural cavity
The wall of the alveoli expands strongly and easily “sticks” to the wall of the chest cavity precisely thanks to negative pressure in the pleural cavity. We can say that the lungs, stretching, follow the movement of the intercostal muscles and the diaphragm. It is unlikely that this would have happened if the pressure in the pleural cavity had increased.
Tip 9. Clearly understand the location of the pleural cavity
The student must clearly understand where he is pleural cavity- between the pulmonary and parietal pleura. IN Unified State Exam in Biology They may even ask about what first aid should be provided to a person with a lung injury and depressurization of the pleural cavity. As you exhale, you need to restore the tightness using rubberized fabric or simply plastic bags, tightly closing the wound.
Tip 10. Be prepared to describe the mechanism of exhalation
How does exhalation occur? Naturally, the intercostal muscles relax, as does the diaphragm. However, I am saying that the external intercostal muscles are relaxing, but the internal ones are contracting. In this case, the chest descends, which leads to a decrease in the volume of the chest cavity and lungs. The air pressure in the alveolar cavity increases. All these processes ensure exhalation.
Dear eighth graders! Before you are tasks from open bank Unified State Examination tasks on the topic “Human Respiratory System”. By completing these tasks, you are preparing for test work on the topic and familiarize yourself with the form for submitting exam material.
1. In a person’s chest cavity there is
1)
2)
3)
4)
pancreas
2. You should breathe through your nose, since in the nasal cavity
1)
gas exchange occurs
2)
a lot of mucus is formed
3)
there are cartilaginous half rings
4)
the air is warmed, purified and neutralized
3. Gas exchange between the outside air and the air of the alveoli in humans is called
1)
tissue respiration
2)
biosynthesis
3)
pulmonary breathing
4)
transport of gases
4. In vertebrates and humans, oxygen is transported from the lungs to the cells
1)
chlorophyll
2)
3)
hemoglobin
4)
albumen
5. Cells are most sensitive to lack of oxygen
1)
2)
brain
3)
liver and kidneys
4)
stomach and intestines
6. Center breathing reflexes is located in
1)
cerebellum
2)
midbrain
3)
medulla oblongata
4)
diencephalon
7. The human airways are lined with tissue on the inside
1)
connecting
2)
muscular striated
3)
epithelial
4)
muscle smooth
8. In the human body it interacts with oxygen in the air
1)
Rh factor determining protein
2)
red blood cell hemoglobin
3)
plasma fibrinogen
4)
plasma glucose
9. Which group? without conditioned reflexes include sneezing and coughing?
1)
protective
2)
3)
indicative
4)
1)
2)
nasopharynx
3)
4)
11. Establish the sequence of arrangement of the respiratory organs through which air enters during inhalation.
A)
nasopharynx
B)
IN)
lung alveoli
G)
nasal cavity
D)
E)
12. The location of the centers that regulate the processes of respiration and cardiovascular activity is
1)
midbrain
2)
cerebellum
3)
medulla
4)
13. Determine the sequence of air movement to the lungs through the human respiratory tract.
1)
nasal cavity nasopharynx trachea larynx bronchi pulmonary vesicles
2)
nasal cavity nasopharynx larynx bronchi trachea pulmonary vesicles
3)
nasal cavity nasopharynx larynx trachea bronchi pulmonary vesicles
4)
nasal cavity nasopharynx bronchi larynx trachea pulmonary vesicles
Beginning of the form
15. What number indicates in the figure the organ into which air enters from the larynx?
1)
2)
3)
4)
End of form
16. What formed elements of blood carry oxygen from the lungs
to fabrics?
1)
phagocytes
2)
red blood cells
3)
lymphocytes
4)
platelets
17. The breakdown of oxyhemoglobin into hemoglobin and oxygen occurs in
1)
arteries
2)
veins
3)
capillaries of the pulmonary circulation
4)
capillaries great circle blood circulation
18 Participates in the transport of oxygen from the lungs to the tissues
1)
fibrinogen
2)
hemoglobin
3)
insulin
4)
adrenalin
19. What process occurring in the human body is shown in the figure? What underlies this process and how does the composition of the blood change as a result? Explain your answer.
20. Blood hemoglobin, which takes part in the transport of oxygen and carbon dioxide, is contained in
1)
platelets
2)
lymphocytes
3)
phagocytes
4)
red blood cells
21. In the cells of the human body, during the process of respiration,
1)
release of oxygen
2)
movement of organic and inorganic substances
3)
oxidation of organic substances releasing energy
4)
formation of organic substances from inorganic substances
22. Which tissue is involved in the transport of oxygen and carbon dioxide?
1)
nervous
2)
muscular
3)
epithelial
4)
connecting
23 Establish a correspondence between the process occurring in the human body and the organ system that is involved in its implementation.
PROCESS
ORGAN SYSTEM
A)
air entering the body from external environment
B)
ensuring gas exchange in tissues
IN)
air humidification and detoxification
G)
delivery of substances to body cells
D)
removal of carbon dioxide from the body
1)
circulatory
2)
respiratory
24. Tell us about the methods of regulation breathing movements in humans.
Human respiratory system- a set of organs and tissues that ensure the exchange of gases in the human body between the blood and the external environment.
Respiratory system function:
oxygen entering the body;
removal of carbon dioxide from the body;
removal of gaseous metabolic products from the body;
thermoregulation;
synthetic: some are synthesized biologically in lung tissue active substances: heparin, lipids, etc.;
hematopoietic: mature in the lungs mast cells and basophils;
depositing: the capillaries of the lungs can accumulate large amounts of blood;
absorption: ether, chloroform, nicotine and many other substances are easily absorbed from the surface of the lungs.
The respiratory system consists of the lungs and airways.
Pulmonary contractions are carried out using the intercostal muscles and the diaphragm.
Respiratory tract: nasal cavity, pharynx, larynx, trachea, bronchi and bronchioles.
The lungs consist of pulmonary vesicles - alveoli
Rice. Respiratory system
Airways
nasal cavity
The nasal and pharyngeal cavities are the upper respiratory tract. The nose is formed by a system of cartilage, thanks to which the nasal passages are always open. At the very beginning of the nasal passages there are small hairs that trap large dust particles in the inhaled air.
The nasal cavity is lined internally with mucous membrane, permeated blood vessels. It contains a large number of mucous glands (150 glands/$cm^2$ of mucous membrane). Mucus prevents the proliferation of microbes. From blood capillaries A large number of leukocytes-phagocytes appear on the surface of the mucous membrane, which destroy the microbial flora.
In addition, the mucous membrane can change significantly in its volume. When the walls of its vessels contract, it contracts, the nasal passages expand, and the person breathes easily and freely.
The mucous membrane of the upper respiratory tract is formed ciliated epithelium. The movement of the cilia of an individual cell and the entire epithelial layer is strictly coordinated: each previous cilium in the phases of its movement is ahead of the next one for a certain period of time, therefore the surface of the epithelium is wave-like - “flickers”. The movement of the cilia helps keep the airways clear by removing harmful substances.
Rice. 1. Ciliated epithelium of the respiratory system
The olfactory organs are located in the upper part of the nasal cavity.
Function of the nasal passages:
filtration of microorganisms;
dust filtration;
humidification and warming of inhaled air;
mucus flushes everything filtered into the gastrointestinal tract.
The cavity is divided into two halves by the ethmoid bone. Bone plates divide both halves into narrow, interconnected passages.
Open into the nasal cavity sinuses air-bearing bones: maxillary, frontal, etc. These sinuses are called paranasal sinuses. They are lined with a thin mucous membrane containing a small number of mucous glands. All these septa and shells, as well as numerous accessory cavities of the cranial bones, dramatically increase the volume and surface of the walls of the nasal cavity.
paranasal sinuses
Paranasal sinuses (paranasal sinuses) - air cavities in the bones of the skull, communicating with the nasal cavity.
In humans, there are four groups of paranasal sinuses:
maxillary (maxillary) sinus - a paired sinus located in the upper jaw;
frontal sinus - a paired sinus located in the frontal bone;
ethmoid labyrinth - a paired sinus formed by cells of the ethmoid bone;
sphenoid (main) - a paired sinus located in the body of the sphenoid (main) bone.
Rice. 2. Paranasal sinuses: 1 - frontal sinuses; 2 - cells of the lattice labyrinth; 3 - sphenoid sinus; 4 - maxillary (maxillary) sinuses.
The exact meaning of the paranasal sinuses is still not known.
Possible functions of the paranasal sinuses:
decrease in the mass of the anterior facial bones of the skull;
mechanical protection of the head organs during impacts (shock absorption);
thermal insulation of tooth roots, eyeballs etc. from temperature fluctuations in the nasal cavity during breathing;
humidification and warming of inhaled air due to slow air flow in the sinuses;
perform the function of a baroreceptor organ (additional sensory organ).
Maxillary sinus ( maxillary sinus) - steam room paranasal sinus nose, occupying almost the entire body of the maxillary bone. The inside of the sinus is lined with a thin mucous membrane of ciliated epithelium. There are very few glandular (goblet) cells, vessels and nerves in the sinus mucosa.
The maxillary sinus communicates with the nasal cavity through openings on the inner surface of the maxillary bone. Under normal conditions, the sinus is filled with air.
The lower part of the pharynx passes into two tubes: the respiratory tube (in front) and the esophagus (in the back). Thus the pharynx is general department for the digestive and respiratory system.
Larynx
The upper part of the breathing tube is the larynx, located in the front of the neck. Most of the larynx is also lined with a mucous membrane of ciliated epithelium.
The larynx consists of movably interconnected cartilages: cricoid, thyroid (forms Adam's apple, or Adam's apple) and two arytenoid cartilages.
Epiglottis covers the entrance to the larynx when swallowing food. The anterior end of the epiglottis is connected to the thyroid cartilage.
Rice. Larynx
The cartilages of the larynx are connected to each other by joints, and the spaces between the cartilages are covered with connective tissue membranes.
When pronouncing a sound, the vocal cords come together until they touch. With a current of compressed air from the lungs, pressing on them from below, they move apart for a moment, after which, thanks to their elasticity, they close again until the air pressure opens them again.
The vibrations of the vocal cords that arise in this way give the sound of the voice. The pitch of the sound is regulated by the degree of tension of the vocal cords. The shades of the voice depend both on the length and thickness of the vocal cords, and on the structure of the oral cavity and nasal cavity, which play the role of resonators.
The thyroid gland is adjacent to the larynx on the outside.
In front, the larynx is protected by the anterior neck muscles.
Trachea and bronchi
The trachea is a breathing tube about 12 cm long.
It is composed of 16-20 cartilaginous half-rings that do not close at the back; half rings prevent the trachea from collapsing during exhalation.
The back of the trachea and the spaces between the cartilaginous half-rings are covered with a connective tissue membrane. Behind the trachea lies the esophagus, the wall of which, during the passage of a bolus of food, slightly protrudes into its lumen.
Rice. Cross section of the trachea: 1 - ciliated epithelium; 2 - own layer of mucous membrane; 3 - cartilaginous half-ring; 4 - connective tissue membrane
At the level of IV-V thoracic vertebrae, the trachea is divided into two large primary bronchi, extending into the right and left lungs. This place of division is called bifurcation (branching).
The aortic arch bends through the left bronchus, and the right one bends around the azygos vein running from behind to front. According to the expression of old anatomists, “the aortic arch sits astride the left bronchus, and the azygos vein sits on the right.”
Cartilaginous rings located in the walls of the trachea and bronchi make these tubes elastic and non-collapsing, so that air passes through them easily and unhindered. The inner surface of the entire respiratory tract (trachea, bronchi and parts of the bronchioles) is covered with a mucous membrane of multirow ciliated epithelium.
The structure of the respiratory tract ensures warming, humidification and purification of inhaled air. Dust particles move upward with ciliated epithelium and are expelled out with coughing and sneezing. Microbes are neutralized by lymphocytes of the mucous membrane.
lungs
The lungs (right and left) are located in the chest cavity under the protection of the rib cage.
Pleura
Lungs covered pleura.
Pleura- a thin, smooth and moist serous membrane rich in elastic fibers that covers each of the lungs.
Distinguish pulmonary pleura, tightly adherent to lung tissue, and parietal pleura, lining the inside of the chest wall.
At the roots of the lungs, the pulmonary pleura becomes the parietal pleura. Thus, a hermetically closed pleural cavity is formed around each lung, representing a narrow gap between the pulmonary and parietal pleura. The pleural cavity is filled with a small amount of serous fluid, which acts as a lubricant, facilitating the respiratory movements of the lungs.
Rice. Pleura
mediastinum
The mediastinum is the space between the right and left pleural sacs. It is bounded in front by the sternum with costal cartilages, and in the back by the spine.
The mediastinum contains the heart with large vessels, trachea, esophagus, thymus gland, nerves of the diaphragm and thoracic lymphatic duct.
bronchial tree
Deep grooves divide the right lung into three lobes, and the left into two. The left lung on the side facing the midline has a depression with which it is adjacent to the heart.
In every lung with inside includes thick bundles consisting of the primary bronchus, pulmonary artery and nerves, and two pulmonary veins emerge and lymphatic vessels. All these bronchial-vascular bundles, taken together, form lung root. Around the pulmonary roots there are a large number of bronchial lymph nodes.
Entering the lungs, the left bronchus is divided into two, and the right - into three branches according to the number of pulmonary lobes. In the lungs, the bronchi form the so-called bronchial tree. With each new “twig” the diameter of the bronchi decreases until they become completely microscopic bronchioles with a diameter of 0.5 mm. The soft walls of the bronchioles contain smooth muscle fibers and no cartilaginous half-rings. There are up to 25 million such bronchioles.
Rice. Bronchial tree
The bronchioles pass into branched alveolar ducts, which end in pulmonary sacs, the walls of which are strewn with swellings - pulmonary alveoli. The walls of the alveoli are penetrated by a network of capillaries: gas exchange occurs in them.
The alveolar ducts and alveoli are entwined with many elastic connective tissue and elastic fibers, which also form the basis of the smallest bronchi and bronchioles, due to which lung tissue It stretches easily during inhalation and collapses again during exhalation.
alveoli
The alveoli are formed by a network of thin elastic fibers. The inner surface of the alveoli is lined with single-layer squamous epithelium. The epithelial walls produce surfactant- a surfactant that lines the inside of the alveoli and prevents their collapse.
Under the epithelium of the pulmonary vesicles lies a dense network of capillaries into which the terminal branches of the pulmonary artery are divided. Through the contacting walls of the alveoli and capillaries, gas exchange occurs during breathing. Once in the blood, oxygen binds to hemoglobin and is distributed throughout the body, supplying cells and tissues.
Rice. Alveoli
Rice. Gas exchange in the alveoli
Before birth, the fetus does not breathe through the lungs and the pulmonary vesicles are in a collapsed state; after birth, with the very first breath, the alveoli swell and remain straightened for life, retaining a certain amount of air even with the deepest exhalation.
gas exchange area
The completeness of gas exchange is ensured by the huge surface through which it occurs. Each pulmonary vesicle is an elastic sac measuring 0.25 millimeters. The number of pulmonary vesicles in both lungs reaches 350 million. If we imagine that all pulmonary alveoli are stretched and form one bubble with a smooth surface, then the diameter of this bubble will be 6 m, its capacity will be more than $50 m^3$, and the internal surface will be $113 m^2$ and would thus be approximately 56 times larger than the entire skin surface of the human body.
The trachea and bronchi do not participate in respiratory gas exchange, but are only air-conducting pathways.
physiology of breathing
All life processes take place when mandatory participation oxygen, i.e. they are aerobic. The central nervous system is especially sensitive to oxygen deficiency, and primarily cortical neurons, which die earlier than others in oxygen-free conditions. As is known, the period clinical death should not exceed five minutes. Otherwise, irreversible processes develop in the neurons of the cerebral cortex.
Breath- physiological process of gas exchange in the lungs and tissues.
The entire breathing process can be divided into three main stages:
pulmonary (external) respiration: gas exchange in the capillaries of the pulmonary vesicles;
transport of gases by blood;
cellular (tissue) respiration: gas exchange in cells (enzymatic oxidation nutrients in mitochondria).
Rice. Pulmonary and tissue respiration
Red blood cells contain hemoglobin, a complex iron-containing protein. This protein is capable of attaching oxygen and carbon dioxide to itself.
Passing through the capillaries of the lungs, hemoglobin attaches 4 oxygen atoms to itself, turning into oxyhemoglobin. Red blood cells transport oxygen from the lungs to body tissues. In tissues, oxygen is released (oxyhemoglobin is converted into hemoglobin) and carbon dioxide is added (hemoglobin is converted into carbohemoglobin). Red blood cells then transport carbon dioxide to the lungs for removal from the body.
Rice. Transport function of hemoglobin
The hemoglobin molecule forms a stable compound with carbon monoxide II ( carbon monoxide). Carbon monoxide poisoning leads to the death of the body due to oxygen deficiency.
mechanism of inhalation and exhalation
Inhale- is an active act, as it is carried out with the help of specialized respiratory muscles.
The respiratory muscles include intercostal muscles and diaphragm. When inhaling deeply, the muscles of the neck, chest and abs are used.
The lungs themselves do not have muscles. They are not able to stretch and contract on their own. The lungs only follow the chest, which expands thanks to the diaphragm and intercostal muscles.
During inhalation, the diaphragm lowers by 3-4 cm, as a result of which the volume of the chest increases by 1000-1200 ml. In addition, the diaphragm moves the lower ribs to the periphery, which also leads to an increase in the capacity of the chest. Moreover, the stronger the contraction of the diaphragm, the more the volume of the thoracic cavity increases.
The intercostal muscles, contracting, raise the ribs, which also causes an increase in the volume of the chest.
The lungs, following the stretching chest, themselves stretch, and the pressure in them drops. As a result, a difference is created between the pressure atmospheric air and pressure in the lungs, air rushes into them - inhalation occurs.
Exhalation, Unlike inhalation, it is a passive act, since muscles do not take part in its implementation. When the intercostal muscles relax, the ribs lower under the influence of gravity; the diaphragm, relaxing, rises, taking its usual position, and the volume of the chest cavity decreases - the lungs contract. Exhalation occurs.
The lungs are located in a hermetically sealed cavity formed by the pulmonary and parietal pleura. In the pleural cavity the pressure is below atmospheric (“negative”). Due to negative pressure, the pulmonary pleura is pressed tightly against the parietal pleura.
A decrease in pressure in the pleural space is the main reason for the increase in lung volume during inhalation, that is, it is the force that stretches the lungs. Thus, during an increase in the volume of the chest, the pressure in the interpleural formation decreases, and due to the pressure difference, air actively enters the lungs and increases their volume.
During exhalation, the pressure in the pleural cavity increases, and due to the pressure difference, air escapes and the lungs collapse.
Chest breathing carried out mainly by the external intercostal muscles.
Abdominal breathing carried out by the diaphragm.
Men have abdominal breathing, while women have thoracic breathing. However, regardless of this, both men and women breathe rhythmically. From the first hour of life, the breathing rhythm is not disturbed, only its frequency changes.
A newborn baby breathes 60 times per minute; in an adult, the resting respiratory rate is about 16-18. However, during physical activity, emotional arousal or increased body temperature, the respiratory rate may increase significantly.
Vital capacity of the lungs
Vital capacity of the lungs (VC)- this is the maximum amount of air that can enter and exit the lungs during maximum inhalation and exhalation.
The vital capacity of the lungs is determined by the device spirometer.
In an adult healthy person Vital vital capacity varies from 3500 to 7000 ml and depends on gender and indicators physical development: for example, chest volume.
Vital fluid consists of several volumes:
Tidal volume (TO)- this is the amount of air that enters and leaves the lungs during quiet breathing (500-600 ml).
Inspiratory reserve volume (IRV)) is the maximum amount of air that can enter the lungs after a quiet inhalation (1500 - 2500 ml).
Expiratory reserve volume (ERV)- this is the maximum amount of air that can be removed from the lungs after a quiet exhalation (1000 - 1500 ml).
regulation of breathing
Breathing is regulated by nervous and humoral mechanisms, which come down to ensuring the rhythmic activity of the respiratory system (inhalation, exhalation) and adaptive respiratory reflexes, that is, changing the frequency and depth of respiratory movements that take place under changing conditions of the external environment or the internal environment of the body.
The leading respiratory center, as established by N. A. Mislavsky in 1885, is the respiratory center located in the region medulla oblongata.
Respiratory centers are found in the hypothalamus region. They take part in the organization of more complex adaptive respiratory reflexes, necessary when the conditions of the organism’s existence change. In addition, respiratory centers are located in the cerebral cortex, carrying out higher forms of adaptation processes. The presence of respiratory centers in the cerebral cortex is proven by the formation of conditioned respiratory reflexes, changes in the frequency and depth of respiratory movements that occur during various emotional states, as well as voluntary changes in breathing.
Vegetative nervous system innervates the walls of the bronchi. Their smooth muscles are supplied with centrifugal fibers of the vagus and sympathetic nerves. Vagus nerves cause contraction of the bronchial muscles and narrowing of the bronchi, and sympathetic nerves relax the bronchial muscles and dilate the bronchi.
Humoral regulation: in exhalation is carried out reflexively in response to an increase in the concentration of carbon dioxide in the blood.
Establish the correct sequence of processes of normal inhalation and exhalation in a person, starting with an increase in the concentration of CO 2 in the blood.
Write down the corresponding sequence of numbers in the table.
1) contraction of the diaphragm
2) increasing oxygen concentration
3) increase in CO 2 concentration
4) stimulation of chemoreceptors of the medulla oblongata
6) relaxation of the diaphragm
Explanation.
The sequence of processes of normal inhalation and exhalation in humans, starting with an increase in the concentration of CO 2 in the blood:
3) increase in CO 2 concentration →4) excitation of chemoreceptors of the medulla oblongata →6) relaxation of the diaphragm →1) contraction of the diaphragm →2) increase in oxygen concentration →5) exhalation
Answer: 346125
Note.
The respiratory center is located in the medulla oblongata. Under the influence of carbon dioxide in the blood, excitement arises in it, it is transmitted to the respiratory muscles, and inhalation occurs. In this case, the stretch receptors in the walls of the lungs are excited, they send an inhibitory signal to the respiratory center, it stops sending signals to the respiratory muscles, and exhalation occurs.
If you hold your breath for a long time, carbon dioxide will increasingly excite the respiratory center, and eventually breathing will resume involuntarily.
Oxygen does not affect the respiratory center. When there is an excess of oxygen (hyperventilation), cerebral vasospasm occurs, which leads to dizziness or fainting.
Because This task causes a lot of controversy, because the sequence in the answer is not correct - a decision was made to send this task to unused.
Anyone who wants to learn more about the mechanisms of respiratory regulation can read the article “Physiology of the respiratory system.” About chemoreceptors at the very end of the article.
Respiratory center
The respiratory center should be understood as a set of neurons of specific (respiratory) nuclei of the medulla oblongata, capable of generating a respiratory rhythm.
Under normal (physiological) conditions, the respiratory center receives afferent signals from peripheral and central chemoreceptors, signaling, respectively, the partial pressure of O 2 in the blood and the concentration of H + in the extracellular fluid of the brain. During wakefulness, the activity of the respiratory center is regulated additional signals emanating from various structures of the central nervous system. In humans, these are, for example, structures that support speech. Speech (singing) can significantly deviate from normal level blood gases, even reduce the reaction of the respiratory center to hypoxia or hypercapnia. Afferent signals from chemoreceptors interact closely with other afferent stimuli from the respiratory center, but ultimately chemical or humoral control of breathing always dominates neurogenic control. For example, a person voluntarily cannot hold his breath indefinitely due to hypoxia and hypercapnia increasing during respiratory arrest.
The rhythmic sequence of inhalation and exhalation, as well as changes in the nature of respiratory movements depending on the state of the body, are regulated by the respiratory center located in the medulla oblongata.
In the respiratory center there are two groups of neurons: inspiratory and expiratory. When inspiratory neurons are excited, providing inspiration, the activity of expiratory neurons nerve cells inhibited, and vice versa.
In the upper part of the cerebral pons (pons) there is a pneumotaxic center, which controls the activity of the lower inhalation and exhalation centers and ensures the correct alternation of cycles of respiratory movements.
The respiratory center, located in the medulla oblongata, sends impulses to the motor neurons of the spinal cord that innervate the respiratory muscles. The diaphragm is innervated by axons of motor neurons located at the level of the III-IV cervical segments of the spinal cord. Motor neurons, the processes of which form the intercostal nerves innervating the intercostal muscles, are located in the anterior horns (III-XII) of the thoracic segments of the spinal cord.
The respiratory center performs two main functions in the respiratory system: motor, or motor, which manifests itself in the form of contraction of the respiratory muscles, and homeostatic, associated with changes in the nature of breathing when the content of O 2 and CO 2 changes in internal environment body.
Diaphragmatic motor neurons. Forms the phrenic nerve. The neurons are located in a narrow column in the medial part of the ventral horns from CIII to CV. The phrenic nerve consists of 700-800 myelinated and more than 1500 unmyelinated fibers. The overwhelming majority of fibers are axons of α-motoneurons, and a smaller part is represented by afferent fibers of muscle and tendon spindles localized in the diaphragm, as well as receptors of the pleura, peritoneum and free nerve endings of the diaphragm itself.
Motor neurons of spinal cord segments innervating the respiratory muscles. At the CI-CII level, near the lateral edge of the intermediate zone of gray matter, there are inspiratory neurons that are involved in regulating the activity of intercostal and phrenic motor neurons.
Motor neurons innervating the intercostal muscles are localized in the gray matter of the anterior horns at the level from TIV to TX. Moreover, some neurons regulate predominantly respiratory, while others regulate predominantly postural-tonic activity of the intercostal muscles. Motor neurons innervating muscles abdominal wall, are localized within the ventral horns of the spinal cord at the level of TIV-LIII.
Generation of respiratory rhythm.
Spontaneous activity of neurons in the respiratory center begins to appear towards the end of the period intrauterine development. This is judged by the periodically occurring rhythmic contractions of the inspiratory muscles in the fetus. It has now been proven that excitation of the respiratory center in the fetus appears due to the pacemaker properties of the network of respiratory neurons in the medulla oblongata. In other words, initially respiratory neurons are capable of self-excitation. The same mechanism supports ventilation of the lungs in newborns in the first days after birth. From the moment of birth, as synaptic connections of the respiratory center with various departments The central nervous system pacemaker mechanism of respiratory activity quickly loses its physiological significance. In adults, the rhythm of activity in the neurons of the respiratory center arises and changes only under the influence of various synaptic influences on the respiratory neurons.
The respiratory cycle is divided into an inhalation phase and an exhalation phase regarding the movement of air from the atmosphere towards the alveoli (inhalation) and back (exhalation).
Two phases external respiration correspond to three phases of activity of neurons in the respiratory center of the medulla oblongata: inspiratory, which corresponds to inhalation; post-inspiratory, which corresponds to the first half of exhalation and is called passive controlled expiration; expiratory, which corresponds to the second half of the exhalation phase and is called the active expiration phase.
The activity of the respiratory muscles during the three phases of neural activity of the respiratory center changes as follows. During inspiration, the muscle fibers of the diaphragm and external intercostal muscles gradually increase the force of contraction. During the same period, the muscles of the larynx are activated, which expand the glottis, which reduces resistance to air flow during inspiration. The work of the inspiratory muscles during inspiration creates a sufficient supply of energy, which is released in the post-inspiratory phase, or in the phase of passive controlled expiration. During the post-inspiratory phase of breathing, the volume of air exhaled from the lungs is controlled by the slow relaxation of the diaphragm and the simultaneous contraction of the muscles of the larynx. Narrowing of the glottis in the post-inspiratory phase increases resistance to expiratory airflow. This is a very important physiological mechanism that prevents the collapse of the airways of the lungs during sharp increase speed air flow on exhalation, for example during forced breathing or protective reflexes of coughing and sneezing.
In the second phase of exhalation, or the phase of active expiration, the expiratory air flow increases due to the contraction of the internal intercostal muscles and the muscles of the abdominal wall. Absent during this phase electrical activity diaphragm and external intercostal muscles.
Regulation of the activity of the respiratory center.
Regulation of the activity of the respiratory center is carried out with the help of humoral, reflex mechanisms and nerve impulses coming from the overlying parts of the brain.
Humoral mechanisms. A specific regulator of the activity of neurons in the respiratory center is carbon dioxide, which acts on respiratory neurons directly and indirectly. Chemoreceptors sensitive to carbon dioxide were found in the reticular formation of the medulla oblongata, near the respiratory center, as well as in the area of the carotid sinuses and aortic arch. With an increase in carbon dioxide tension in the blood, chemoreceptors are excited, and nerve impulses are sent to inspiratory neurons, which leads to an increase in their activity.
Answer: 346125
