Lungs are paired respiratory organs. The characteristic structure of the lung tissue is laid more on the second month of fetal development. After giving birth, respiratory system continues to evolve, eventually being formed to approximately 22-25 years. After the age of 40 lung tissue is gradually aging.
Its name in the Russian language, this body was due to the property not to sink in the water (due to air content inside). The Greek and Latin pneumon - pulmunes also translated as "easy". Hence, inflammatory lesion of the body is called "pneumonia". A treatment of this and other diseases of the lung tissue involved in doctor-pulmonologist.
location
In humans, the lungs are in the thoracic cavity and take at the same time it most. The thoracic cavity is limited to the front and rear edges of the diaphragm is at the bottom. It also is the mediastinum, containing the trachea, the main organ of the circulatory - heart, large (main) vessels, the esophagus, and some other important structures of the human body. The thoracic cavity does not communicate with the external environment.
Each of these bodies is covered completely outside the pleura - smooth serosa having two sheets. One merges with lung tissue, the other - with the thoracic cavity and the mediastinum. Formed therebetween pleural cavity filled with a small amount of liquid. Due to the negative pressure in the pleural cavity and the surface tension of the liquid in the lung tissue retained therein in the expanded condition. In addition to this, the pleura reduces its friction on the rib surface during the act of breathing.
external structure
Lung tissue resembles fine sponge pink. With age, and also in pathological processes of the respiratory system, long-term smoking color changes and pulmonary parenchyma becomes darker.
Lung It has an irregular cone, The tip of which faces upwards and is located in the neck, speaking a few centimeters above the clavicle. At the bottom, at the boundary of the diaphragm, pulmonary surface has concave form. The front and rear surface thereof is convex (while it is sometimes observed on the prints from the edges). The inner side (medial) surface is bordered by the mediastinum and also has a concave form.
On the medial surface of each lung are the so-called gateway through which to penetrate the lung tissue main bronchus and blood vessels - arteries and two veins.
The dimensions of both lungs are not the same: right approximately 10% more left. This is due to the location of the heart in the chest cavity: the left of the median line of the body. This "neighborhood" and causes their characteristic shape: the right is shorter and wider, and the left - a long and narrow. The shape of the body depends on the human body. For example, in lean people, both lungs are narrower and longer than the mast, which is caused by the structure of the chest.
In human lung tissue have pain receptors, and the occurrence of pain in certain diseases (e.g., pneumonia) usually associated with a pathological process involving pleura.
What is in LIGHT
Light in human anatomy are divided into three main components: the bronchi, bronchioles and acini.
Bronchi and bronchioles
Bronchi are hollow tubular branch trachea and connect it directly with lung tissue. The main function of the bronchi is vozduhoprovedenie.
Approximately at the level of the fifth thoracic vertebra trachea is divided into two main bronchi: right and left, which are then sent to the respective lungs. In lung anatomy important bronchial branching system, Whose appearance resembles the tree crowns, so it is called - "bronchial tree".
Upon entering the main bronchus to lung tissue it is initially divided into equity and then - into smaller segmental (respectively each lung segment). Subsequent dichotomy (pair) the division of the segmental bronchi eventually leads to the formation of terminal and respiratory bronchioles - the smallest branches of the bronchial tree.
Each bronchus consists of three layers:
- outer (connective tissue);
- fibromuscular (contains cartilage);
- an inner mucosa, which is covered with ciliated epithelium.
By decreasing the diameter of the bronchus (branching process) cartilaginous tissue and mucosa gradually disappears. The smallest bronchi (bronchioles) are not contained in the structure of the cartilage, the mucosa is also absent. Instead, there is a thin layer of cuboidal epithelium.
acinus
Dividing terminal bronchioles lead to the formation of several orders airway. From each of the respiratory bronchioles branch off in all directions, alveolar ducts, which terminate blindly air sacs (alveoli). Sheath densely covered alveolar capillary network. This is where gas exchange is performed between the oxygen inhaled and exhaled carbon dioxide.
The diameter of the alveoli is very small and varies from 150 micrometers at the newborn child to 280-300 microns of an adult.
The inner surface of each alveolus is covered with a special substance - surfactant. It prevents it wears off, and the liquid penetration into the structure of the respiratory system. In addition, the surfactant has bactericidal properties and is involved in several immune reactions protection.
The structure, which includes respiratory bronchioles and emanating from her alveolar ducts and sacs, called primary lung slice. It is established that one of the terminal bronchiole proceeds approximately 14-16 airway. Consequently, such a number of primary lung lobes forms a main structural unit parenchymal lung tissue - acinus.
The name of this anatomical and functional structure was due to the distinctive appearance that resembles a bunch of grapes (lat. Acinus - «bunch"). In humans, there are approximately 30,000 acini.
The total surface area of the respiratory lung tissue due alveoli ranges from 30 square meters. meters and during exhalation to about 100 sq. meters during inspiration.
Share and segments easily
Acini formed lobules, Which are formed from segmentsAnd segment - shareConstituting the whole lung.
The right lung has three share, in the left - two (due to the smaller its size). Both light stands upper and lower lobe, and the right - and even the average. Between a segregated fraction grooves (fissures).
share divided into segmentsWho do not have a visible distinction in the form of connective tissue layers. Usually in the right lung, there are ten segments in the left - eight. Each segment contains in its composition segmental bronchus and a corresponding branch of the pulmonary artery. Appearance pulmonary segment resembles a pyramid of irregular shape, the tip of which faces the pulmonary gate, and base - to pleural sheets.
Outer percentage of each lung has a front segment. The right lung is also a apical and posterior segments, and in the left - apex-posterior and two reed (upper and lower).
The lower lobe of each lung distinguish upper, antero, and lateralno- zadnebazalny segments. In addition, the left lung is determined mediobasal segment.
In the middle lobe of the right lung allocate two segments: the medial and lateral.
Segment human lung separation is necessary to determine the precise localization of pathological changes lung tissue, which is particularly important for medical practitioners, for example, in the treatment and monitoring of the course pneumonia.
FUNCTIONAL PURPOSE
The primary function is gas exchange of the lung, in which carbon dioxide is removed from the blood with simultaneous saturating it with oxygen, necessary for normal metabolism of almost all organs and tissues of the human body.
Inhalation oxygenated the air of the bronchial tree penetrates into the alveoli. There also enters "spent" blood from the pulmonary circulation, containing a large amount of carbon dioxide. After carbon dioxide gas exchange again for bronchial tree is expelled during exhalation. A oxygenated blood enters the systemic circulation and is directed more to the organs and systems of human body.
act of breathing in humans is involuntary, reflex. It is responsible for this particular brain structure - the medulla oblongata (respiratory center). According to the degree of blood carbonation regulated rate and depth of respiration, which becomes deeper and more with increasing concentration of the gas.
In light no muscle tissue. Therefore, their participation in the act of breathing entirely passive: the expansion and contraction during movement of the chest.
The breathing exercise involving muscle of the diaphragm and chest. Respectively identify two types of breathing: abdominal and breast.
Inspiratory volume of the thoracic cavity increases, it a negative pressure (Below atmospheric pressure), which allows air to freely flow into the lungs. This reduction is carried carcass diaphragm muscle and the chest (intercostal muscles), which leads to a raising and divergence edges.
On exhalation, on the contrary, the pressure rises above atmospheric, and excretion carbonated air produced by substantially passive. The volume of the thoracic cavity decreases due to relaxation of the respiratory muscles and lower the ribs.
In some pathological conditions in the act of breathing include the so-called auxiliary respiratory muscles: neck, abdominal, etc...
The amount of air that a person inhales and exhales at a time (tidal volume) is about half a liter. In a moment it occurs on average 16-18 breaths. During the day, through the lung tissue it passes over 13 000 liters of air!
The average lung capacity of about 3-6 liters. In humans, it is superfluous: during inspiration, we use only about one-eighth of the container.
In addition to gas exchange in the lungs and the person has other functions:
- Participation in maintaining acid-alkaline balance.
- Elimination of toxins, essential oils, alcohol vapor, and so. D.
- Maintaining water balance of the body. Normally, the lungs evaporates about half a liter of water per day. In extreme situations, the daily excretion of water can reach 8-10 liters.
- The ability to detain and dissolve the conglomerates of cells, fat microembolisms and fibrin clots.
- Participation in the clotting (coagulation).
- Phagocytic activity - part of the immune system.
Therefore, the structure and function of the human lung are closely related, thus ensuring the smooth operation of the entire human body.
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