Without breathing, a person will not live even seven minutes. This is the most important function of the body, although we do not make special efforts for its implementation. How does the inspiration and expiration mechanism work? What organs and systems does he use?
Human breath
For life, we need oxygen. This is a key element of breathing that provides metabolism and energy in the body. It enters the lungs in a gaseous state along with air, spreading throughout the body, where it is oxidized and excreted from the body in the same way.
The breathing mechanism - inhalation-exhalation - works continuously. At one minute, a person makes about 14 such movements, in infants the number increases to 50. The person’s breathing is one of the few processes that can be controlled consciously and unconsciously.
With a small effort of will, we can regulate its frequency and duration, and if necessary, completely delay it for a few seconds. Such a skill is necessary for a person, for example, while swimming. We are not able to hold our breath for too long; the brain dies away without oxygen within five to seven minutes.
Inhalation and Exhalation Mechanism
Living things have different ways and mechanisms of breathing. Some use the entire surface of the body, others use the gills, others have the lungs. In humans, there is internal tissue and external pulmonary respiration. Tissue represents the consumption of oxygen by cells of internal organs.
Pulmonary respiration is carried out in two stages: gas exchange with the alveoli, and then with blood. Air from the atmosphere, saturated with oxygen, passes through the nasopharynx, larynx, tracheobronchial tree and enters the pulmonary alveoli.
They give atmospheric air to the blood, which carries it to all organs in the vessels. From the blood, air enters the alveoli, saturated with carbon dioxide, which is excreted from the body along with exhalation.
The mechanism of inhalation and exhalation provides ventilation of the alveoli. It is carried out with the help of the respiratory muscles, which expands the chest, allowing you to draw up to 7 liters of air per minute into the lungs. The increase occurs by raising the ribs (usually in women) or by flattening the diaphragm (in men, as well as during physical exertion).
Upper respiratory tract
The value of the respiratory organs is not the same; each of them has its own functions. The human respiratory system includes the upper and lower respiratory tract, and the respiratory organs themselves. The upper paths are represented by the nasal cavity, nasopharynx, oropharynx, and partially the oral cavity.
The inner part of the nasal cavity is covered with mucous membrane and hairs. It acts as a filter, the main task of which is to prevent the ingress of dust, dirt and germs into the body. Here the air warms and moistens.
By two channels of the nostrils, the cavity is connected with the nasopharynx. It, in turn, is connected to the Eustachian tube, which is responsible for balancing the pressure.
In the oropharynx, the respiratory and alimentary passages are crossed. It is limited to the posterior and lateral walls of the oral cavity and is responsible for the clear pronunciation. During eating and talking, the soft palate rises, preventing food and air from entering the nasopharynx.
Lower respiratory tract
The pharynx conducts air to the larynx. It is from her that the lower respiratory tract begins. The larynx is formed by paired and unpaired cartilage, interconnected by ligaments and muscles. Muscle contraction changes the shape of the glottis and the tension of the ligaments, as a result of which sounds are formed.
The larynx connects to the tube up to 15 centimeters in length - the trachea. Its end bifurcates, passing into the bronchi. The main function of the trachea is to pass air into the lungs and back. It is mobile and consists of cartilage, so air passes through it with any rotation of the neck.
The bronchi are a paired organ and enter the lungs. The left bronchus is thinner than the right, the right is more vertical. They are formed by cartilage rings and smooth muscles, inside are covered with mucous membrane.
Each of them has branches - there are eleven in the right, ten in the left. Lymph nodes on the branches carry lymph from the lung tissue, blood is carried through the bronchial arteries from the thoracic aorta.
Lungs
The lungs are sometimes referred to as the lower respiratory tract. They are located in the chest cavity on the left and right sides of the heart, and their base is located on the diaphragm. Outside, the lungs are covered with pleura and pleural sac. Between them is a lubricating fluid that prevents friction.
The lungs consist of several segments (right of three, left of two), which are divided into ten smaller lobes. Inside them are the bronchi, which, in turn, are divided into small bronchioles, acini, and end with alveolar sacs.
Sacks are numerous alveoli - spherical formations, braided by capillaries. In an adult, their amount is about 700 million. They are responsible for gas exchange.
From them, oxygenated air enters the blood vessels. Blood through the arteries moves directly to the heart, and along the way it spreads through all tissues and organs. In return, they donate blood saturated with carbon dioxide, which returns through the veins to the alveoli to exit through the lungs, bronchi, trachea, and pharynx back into the atmosphere.
Exercise breathing
The mechanism of inspiration and exhalation is controlled by the center between the hind and medulla oblongata. Respiratory receptors are located on the walls of the bronchi. Air movement is also due to the pressure difference: when inhaling, it is lower than atmospheric pressure, and when exhaling, it is vice versa.
The lungs are able to let in up to 5 thousand milliliters of air when inhaling and exhaling. But with ordinary breathing, the volume is only 500 milliliters. The maximum breath can be approximately 2500 ml.
Man does not exhale absolutely all the air. Part of it is retained in the alveoli, so that the ratio of oxygen and carbon dioxide adheres to the same level. This is the functional residual capacity of the lungs.
In the process of breathing, various muscle groups are involved, depending on the person's activities. The diaphragm is involved during sports training or physical activity, when the abdomen is tensed. In a calm state, the intercostal muscles play a large role.