The basis of the wall of large bronchi, for example, equity and segmental components of cartilage rings - this dense base does not allow the wall to shrink and supports the lumen of the bronchi is always open, which provides free movement of air and inhaling and when breathing. As the diameter decreases the bronchi, the number of cartilage tissue decreases, and smooth muscle tissue appears. In small bronchops, more muscle tissue, in the final bronchiole cartilaginous fabric is completely absent and the basis of their wall is a smooth muscular fabric, so spasm is possible at the level of bronchiole, which happens when attacking bronchial asthma. In respiratory bronchops, in alveolar strokes, the pouch wall is formed by one layer of flat epithelial cells. The wall of the alveolo is also formed by a layer of flat epithelium whose cells are called pneumocites.
Trachea
Right Chief Bronchum Left Chief Bronch
Equity bronchi 2 order.
Segmentary bronchi 3 orders.
Dolkovy bronchi 23 orders.
Finite bronchiols.
Respiratory bronchiols.
Alveolar moves.
Alveolar bags.
Alveola.
The structure of the lungs.
Lightweight are paired parenchymal organs located in breast cavity. They have a cone-shaped form. On the light, the top is isolated (above the clavicle by 1.5-2 cm.) And the base is distinguished that lies on the diaphragm. Light has three surfaces: outdoor or rib; lower - diaphragmal; Medi-mediastyle or media.
On the medial surface there are gates.
Make a conclusion about the features of the lungs vascular bed:
All structures located in the field of the lung gate form the root of the lung. Inflammation of these structures is estimated as roasting pneumonia, in contrast to focal pneumonia, when the walls of the Alveol are inflated.
Each lung is divided into parts, they are called shares. The right lung is divided into three shares, and left for two. Shares separately separated from each other deep furrows. In the furrows are partitions from connective tissue.
Perform a schematic drawing. "Outdoor structure of the lung."
Shares are divided into segment. In every light ten segments. Segments are divided into slices, which in every light about a thousand. Between themselves and segments and slices are separated by a connective tissue. Lung connecting fabric, which forms partitions between shares, segments and slices are called interstitial and intermediate lung cloth . Inflammation of this tissue is also regarded as interstitial pneumonia.
Light outside is covered with a serous shell, which is called pleura. As all serous shells, it consists of two sheets: internal visceral, which gently arrives at the pulmonary fabric, and the outer parietal (intternate), which goes to the inner surface of the lungs. Between the leaves closed space is pleural cavityIt is filled with a small amount of serous fluid. Inflammation of the pleura is called pleurisy. When pleuthing in the cavity is formed a large number of Serous or purulent liquids, liquid squeezes light and it turns off from breathing. Help with such pathology can be rendered by conducting pleural puncture (puncture). Violation of the integrity of the pleura and entering the pleural cavity of atmospheric air pneumothorax. Hitting the pleural cavity of blood called hemotorax.
Terminal bronchiols. The wall of terminal bronchioles Consists of 2 thinned shells: 1) mucosa and 2) adventitial.
Mucous membrane Consists of 3 layers: 1) epithelial plate, 2) own plate and 3) muscle plate.
Epithelial plate Presented by cubic semi-epithelium, among the cells of which there are Cellula Secretory cells, Cembal (EpithelioCytus Limbatus) and the luxurious (epithelioocytus aciliatus) cells.
Clari secretory cells A narrow base is on the basement membrane, their wide apical part is keenly spinning, the core - round shape, in the cytoplasm there is a set of Golgi, smooth EPS, mitochondria and secretory granules.
^ Function of secretory cells - Lipoproteins and glycoproteins (surfactant components) and enzymes involved in the disinfectant of toxins entering the respiratory tract are isolated.
Safe (brush) Cells have a barrel shape, i.e. a narrow base, a narrow apical part and a wide middle part. The kernels have a round shape, in the cytoplasm - organhalles of the total value, on the apical surface there are microvills forming the cut.
^ Function of cacular cells - Smells perceive (olfactory function).
Survective epitheliocytes They have a prismatic form, are somewhat towers over the rest of the epithelocytes. In their cytoplasm there are a complex of Golgi, Mitochondria, EPS, the inclusion of glycogen granules and secretory granules. Their function is unknown.
Respiratory Light Division
Pulmonary acinus - This is a structural and functional unit of the lungs. The respiratory part of the lung begins with acinus. It is the branching of the respiratory bronchioles of the 1st order. How does this bronchiolate branches? Respiratory bronchiola 1 -th order is divided into 2 respiratory bronchiols of the 2nd order, each of which branches on 2 bronchiols of the 3rd order, from which 2 alveolar strokes (DUCTUS ALVEOLARIS) are deployed, each alveolar move ends with 2 alveolar bags (Sacculus Alveolaris ). In the walls of respiratory bronchiole, alveolar moves and alveolar bags are available alveola (Alveolus).
Thus, the branching of the respiratory bronchioles of the 1st order and all alveoli included in their composition is the pulmonary acinus.
The acins are separated from each other in layers of loose connective tissue. 12-18 acinuses form a lung slicing, which is also separated from other fractions to the layer of loose connective tissue.
^ Wall of respiratory bronchioles (Bronchiolus Respiratorius) is thinned and includes 2 poorly pronounced shells: 1) mucous membrane and 2) adventitious.
Mucous membrane Respiratory bronchioles are lined with a single-layer cubic luxury epithelium, which sometimes encounters facetime-eyed epithelocytes, there are Clari's secretory cells.
The own plate of the mucous membrane is thinned, the muscular plate is represented by separate circularly located beams of smooth myocytes.
^ Adventic shell Respiratory bronchioles, represented by loose connective tissue, is also thinned, its fibers are moving into an inter-vololar junction tissue.
In the wall of respiratory bronchiole there are separate alveoli. The wall of alveolar strokes and alveolar bags consists of Alveol.
Alveola They are an open bubbles with a diameter of 120-140 μm, opening in the lumen of respiratory bronchioles, alveolar strokes and alveolar bags. There are connective tissue rodges with a thickness of 2-8 microns, in which there are: plexus of elastic fibers, a network of thin collagen fibers, fibroblasts, tissue basophiles and antigen-representing cells that have been said when it was about the trachea epithelium. In partitions, they pass capillaries with a diameter of 5-7 microns, occupying about 75% of the Alveol Square. Alveolas communicate with the help of alveolar pores in a diameter of 10-15 microns.
^ Wall Alveol Alveoocytes (pneumocytes) are selected in the baseal membrane, a strengthened frame, consisting of thin collagen and reticular fibers. Alveolocytes Alveol are represented by 2 main types: respiratory (type I alveolocytes) and secretory (type II alveolocytes). In the wall of the alveoli and on their surface there are alveolar macrophages (Macrophagocytus alveolaris).
^ Respiratory alveolocytes (AlveoLocytus Respiratorius) have a compiled shape, in their cytoplasm there are minor mitochondria and pinocytous bubbles, on the apical surface there are short growns (microvilles). The thickness of the nucleation part of respiratory alveolocytes is 5-6 microns, nuclear-free - 0.2 μm. Opposite the nuclear-free part of the alveolocytes, there is a nuclear-free part of endotheliocytes, the thickness of which is also about 0.2 μm. Therefore, the partition between the air alveoli and the lumen of capillaries, forming the aerohematatic barrier, is about 0.5 microns. The composition of the aerohematic barrier includes: the nuclear-free part of respiratory alveolocytes, the basal membrane of the alveolo, the interlimoolar connecting tissue, the basement of the capillary and endothelium.
^ Function respiratory alveolocyte - gas exchange between air alveoli and hemoglobin erythrocytes (respiratory function).
Secretor alveolocytes, or alveolocyte type II, or large alveolocytes (AlveoCoCYTUS Magnus), are only 5% of total Cells lining the inner surface of the alveoli wall. They have a cubic or oval form, microwaves depart from their cytlemis. The cytoplasm contains: a complex of the Golges, EPS, Ribosomes, Mitochondria, Multivaicular Taurus, Citoophospholiposomes (Plastic Osmofil Taurus), which are markers of type II alveolocyte.
^ Function of secretory alveolocyte - Secrets the components of the surfactant alveolar complex, i.e. phospholipids and proteins.
Surfactant alveolar complex covers the inner surface of the alveolocytes and includes 3 components: 1) the membrane, similar to the structure with cell membranes and includes phospholipids and proteins synthesized by secretory alveolocytes; 2) hypophase (liquid component) consisting of lipoproteins and glycoproteins allocated by Clara's secretory cells; 3) Reserve surfactant.
^ Functional value Surfactant alveolar complex:
1) prevents the internal surface of the walls of the alveoli during the exhalation (if the alveoli sticks out, the next breath would be impossible and death would occur after 4-5 minutes);
2) prevents the penetration of alveoli microorganisms into the surrounding connecting (interstitial) tissue;
3) impedes the flow (transduction) of fluid from the interstitial tissue in the alveoli.
^ Alveolar macrophages They have an overflow form, an oval core and well-developed lysosomal apparatus are located in the alveolo wall or on their outer surface, can migrate from alveoli into an interstitial tissue. In their cytoplasm it contains the inclusion of lipids, during the oxidation of which the inhaled air is warmed, its temperature should correspond to the body temperature.
^
Macrophagha Function
- protective, they phagocytic microorganisms, dust particles, cell fragments and surfactant; Participate in the exchange of lipids, isolated thermal energy.
^
Blood supply of lungs.
The lungs include pulmonary and bronchial artery. The pulmonary artery flows venous blood. This artery branches down the bronchi. Having reached the alveoli, its branches are divided into capillaries with a diameter of 5-7 microns, glossing alveoli. Each capillary simultaneously comes running to two Alveolas. The fact that the red blood cells in the capillaries go in one row, and that the capillaries pass between two alveoli, contacting them, contributes to gas exchange between the air alveol and hemoglobin of red blood cells.
Giving carbon dioxide and enriched with oxygen, the blood from the interlimoolar capillaries enters the system of the pulmonary vein flowing into the left atrium.
Bronchial arteries are branches of aorta; They are also branched down in the course of the bronchi and provide oxygen their wall and pulmonary fabrics. In the wall of the bronchi, the branches of these arteries form plexuses in a submucosal basis and their own plate of the mucous membrane. The arterioles of these plexuses are branched on the capillaries that form a thick network under the basal membrane. Capillaries fall into venous blood-carrying venous blood in small veins fill in the front and rear bronchial veins. At the level of bronchial small caliber between the arteriols of the system of bronchial arteries and venues of the pulmonary veins system, ABA is formed for which part arterial blood Returns to heart.
^ System of lymphatic vessels represented by superficial and deep plexuses of lymphatic capillaries and vessels. Surface plexus is localized in visceral pleura, deep - in the connective tissue around the acinuses, poles, along the proximity of the bronchi and blood vessels. In the wall of the bronchi there are 2 lymphatic plexus: in a submucoscent and in its own plate of the mucous membrane.
Innervation Provided by nervous plexuses located in the layers of connective tissue in the course of blood vessels and bronchi. The composition of the plexus includes intramural nerve ganglia, efferent (sympathetic and parasympathetic) and afferent nerve fibers. Efferent sympathetic fibers are axons of the efferent neurons of sympathetic ganglia, ending with motor effectors on the myocytes of bronchi and blood vessels and secretory effectors on bronchial glands.
Parasympathetic efferent fibers are axons of motor neurons (type i cells) intramural ganglia, to which impulses come from fibers wandering nerve. Efferent parasympathetic fibers also end with motor and secretory effector endings.
When exciting sympathetic fibers, the vessels are narrowed, bronchi expands, breathing is facilitated. When exciting parasympathetic fibers, on the contrary, the vessels are expanding, the bronchi is narrowed, breathing makes it difficult.
Afferent nerve fibers are dendrites of sensitive neurons of nerve ganglia. They end in receptors in the wall of the bronchi and the parenchyma of the lung.
Age-related changes The respiratory system is characterized by an increase in the amount of alveoli and elastic fibers starting from the breast and ending with the youth. In the elderly, the amount of alveoli decreases in the lungs, the elastic fibers of the alveolar frame are destroyed, the connective tissue stromter grows, in which collagen fibers prevail. As a result of these changes, the elasticity of the lungs is reduced, their expansion (lung emphysema) occurs due to the insufficient alvetol saving when exhaling. At the same time, salts are laid in bronchops, the result of which becomes the restriction of respiratory excursions and a decrease in gas exchange.
Pleura, covering lung, called visceral; The lining wall of the chest cavity is parietal. The basis of visceral and parietal pleurr is a connecting fabric lined with mesothelium from the side pleural cavity. Visceral Plevra is characterized in that there is more smooth muscle cells and elastic fibers in its connective tissue. Visceral pleura fibers penetrate into an interstitial lung tissue.
Depending on the excursions of the light mesothelium, the pleura changes its form: when inhaling is complied with a cubic form when exhaling.
^ Features of the respiratory system: Respiratory and lacking.
In the process of respiratory function, gas exchanges are carried out between the hemoglobin of red blood cells and air alveol.
The lack of functions include:
1) thermostat, i.e. warming the inhaled air, if it is cold, and cooling, if it is hot, since the temperature of the air entered into the alveoli must correspond to the body temperature;
2) hydration inhaled air;
3) purification of inhaled air from dust particles, bacteria and other harmful components;
4) immune defense;
5) participation in the exchange of lipids and water-salt metabolism (with exhaled air in the form of a pair, up to 500 ml of water) are daily removed;
6) participation in maintaining the blood coagulation system due to tissue basophils of the lungs;
7) hormonal (secretion of calcitonin, bombiness, norepinephrine, dopamine, serotonin);
8) inactivation of serotonin with the help of monoaminoxidase contained in macrophages and fat cells of the lungs and bradycardine;
9) lysozyme synthesis, interferon and pyrogen of the lung macrophages;
10) the destruction of small blood clots and tumor cells in the lung vessels;
11) blood deposit in pulmonary vessels blood system;
13) olfactory;
14) participation in the allocation of some volatile substances from the body (acetone, ammonia, alcohol pairs).
Lecture 25.
^ Leather and its derivatives
Leather (Cutis) consists of leather actually (corium) and epidermis, covering the skin surface (epidermis), which is a multi-layer flat ornamental epithelium. Under the proper, the subcutaneous fluid fiber, or hypoderma (Hipoderma) is located.
Sources of development. The main cells of the epidermis - keratinocytes and skin appendages (nails, hair, salted, sweat and mammary glands) develop from the skin ectoderma; Melanocytes and Merkel cells of the epidermis - from a nervous crest; Intaepidermal macrophages - from monocytes. The connective tissue base of the skin is developing from the dermatomes of mesodermal somites.
Thick epidermis (600 μm) covers the palm surface of the hands and soles of the foot of the feet, and the thinnest (170 μm) lines the dermis of the face, head.
The structure of the epidermis of the palm surface of the hands and soles of the foot. In this epidermis, the cells form about 50 layers, but all of them can be grouped in 5 main:
1) Basal (Stratum Basale);
2) hipgy (Stratum Spinosum);
3) grained (Stratum Granulosum),
4) brilliant (Stratum Lucidum);
5) Horny (Stratum Corneum).
There is no brilliant layer on the rest of the skin.
^ Basal layer Includes 4 cells of cells: a) keratinocytes, b) melanocytes, c) Merkel cells, d) intapidermal macrophages.
Keratinocytes Make up more than 85% of all cells of this layer, lie on the basal membrane, have a prismatic shape, are connected to each other and other epitheliocytes using despair, and with a basal membrane with a half-texmime.
The cytoplasm of keratinocytes of the basal layer is painted basophilic; Oval, the core is rich in chromatin is located in the basal part of the cell. In cytoplasm there are organhelles of the total value. The granular EPS is synthesized by keratin protein molecules, of which filaments are polymerized. In the cytoplasm there are pygnos granules captured by phagocytosis.
Among the keratinocytes of the basal layer there are stem cells located in the period G 0. However, they can exit this period, join the cell cycle and undergo mitotic division. Substitutional cells formed as a result of division also continue to divide and exposed to differentiation. Due to the division of keratinocytes, the epidermis cells are fully updated for 3-4 weeks. Therefore, the basal layer is called Rostchem. With differentiation, basal keratinocytes are shifted to a hipgy layer.
^ Keratinocyte functions: Regenerator, keratin synthesis, thymsimine synthesis and thymopoietin, stimulating proliferation and antigen-dependent differentiation of T-lymphocytes (substitution of the Timus function).
Melanocytes Not related to desmosms with other cells and the basal membrane, have a passionate shape, weakly painted cytoplasm, which contains: synthetic apparatus, melanin pigment granules and tyrosine and dof-oxidase enzymes involved in the synthesis of this pigment. Pigment is distinguished from cells by exocytosis. The dimensions of melanocytes are significant, so their processes penetrate the hipgy layer. The total number of melanocytes does not exceed 10% of all base layer cells.
^ Merkel cells In short, but wider keratinocytes, contain incorrect form The core, weakly painted cytoplasm, in which there are secretory granules containing bombiness, VIP, Enkephalin. Merkel cells are suitable for nerve fibers that come into contact through Merkel discs.
^ Merkel cell functions:
1) endocrine (secretion of Bombesin, VIP, Enkefalin);
2) participation in the regeneration of epidermis;
3) participation in the regulation of the tone and permeability of blood vessels of the dermis with the help of the VIP and by emulating the allocation of histamine from fat cells;
4) If irritation, therefore, the largest amount is in the most sensitive parts of the skin (the tip of the nose, fingers).
^ Intapidermal macrophage (Langerhans cells) - the largest, have a processful form of their processes deeply introduced into a hipped layer. The kernel most often has a blade form. From the common organelle, the lysosomes containing cholesterinsulfatase enzyme and others are best developed in the cytoplasm contained birbeck granules having a type of tennis racket. These macrophages have the ability to migrate into the dermis and regional lymph nodes.
^ Functions of intapidermal macrophages:
1) produce IL-1, which stimulates the proliferation and differentiation of lymphocytes;
2) perceive antigens and represent their epidermis and regional lymphocytes lymph nodes (participate in immune reactions);
3) Secreter prostaglandins, caileon, epithelial growth factor, enzyme cholesterol sulfate splitting intercellular cement surface part of the horn layer of epidermis;
4) are centers of epidermal proliferative units (EPU), adjusting the proliferation and oroging of keratinocytes with the help of the epithelial growth factor, cailers and cholesterolfatases.
^ Epidermal proliferative units They have the type of columns beginning with the basal layer and ending on the surface of the horn layer of the epidermis, at the base of which are intapidermal macrophages.
^ Hipgy layer It is represented by keratinocytes of the irregular shape, located in 5-10 rows, and intapidermal macrophages. The cores of cells adjacent to the basal layer have a round, and closer to the granular layer - oval shape. From the bodies of cells are growing - spikes in which there are microfibrilles. The spikes of one cell are in contact with the spikes of a different cell. There are desmocomomas between spiked cells.
^ The functions of the cells of the hipged layer: The synthesis of keratin continues, the polymerization of keratinonephylates, of which the beams are formed - tonofibrils. Ceratinosomes are formed in cells, which are plate (lamellar) calves containing lipid substances: cholesterolfathes and ceramides. Together, the basal and hipgy layers form a sprout layer of the epidermis. As the differentiation of the cellular layer cells are shifted to the next, grain layer.
^ Granular layer It is represented by oval or slightly with phenomena, located in 3-4 rows. Cells of cells are piccnotized. In keratinocytes of this layer, the synthesis of keratin continues, the synthesis of Philagrin, Keratolaminin, Inevolution begins. Keratin tonofibrils are packaged using Falagrin to keratogial granules in which Philagrin plays the role of an amorphous matrix. Keratolaminin and Involution is adjusted to the cell cytlemma, providing its high strength and resistance to the effects of Keratinos and Lizosom enzymes, which are activated under the influence of intapidermal macrophages.
By this time, the kernel and organelles begin to decay. As a result of their decay, proteins, lipids, polysaccharides and amino acids are formed, which, joining the beams of tonofibrils, packed with fluorine, take part in the formation of keratogial granules. These granules diffuse diffuse throughout the cytoplasm. The formation of keratogial granules is the 1st stage of the orog.
In keratinocytes of the grain layer, the formation of Keratinos containing lipids (cholesterinsulfate and ceramides) and enzymes continue.
Keratinosoma by exocytosis enroll into the intercellular space, where the cementing substance is formed, gluing grain and shiny layers cells and horny flakes of the horn layer. Thanks to the cementing substance, a waterproof layer of epidermis is formed, which prevents dehydration of the skin and at the same time being a barrier that protects the skin from the penetration of bacteria, chemical substances and other harmful components.
The amount of despair between the cells of the grain layer decreases. With further differentiation of the grain layer cells, they are shifted to the next, shiny layer.
^ Brilliant layer It is represented by compressed cells, the kernel and organelles of which are completely destroyed. There are no desplaomomomomas between and cells, they are interconnected using a cementing substance. Keratogial granules merge into a solid mass called Eleidin. Eleididine's formation is the next, 2nd of the orog. Eleidine is not painted with dyes, but the light refracts well. Therefore, on preparations painted by hematoxylin-eosin, this layer is represented as a brilliant strip. As the differentiation (oroging, keratinization), the cells of the shiny layer are further flattered and shifted into the next, horny layer.
^ Horny layer Consists of 14 coal scales covered with a cytlemma, reinforced protein keratolamine. Knutrice from the thickened cytlemma there are longitudinally located beams of keratin microfibrils, devoid of philalaga, which is split up to the amino acids that are part of keratin. Evalted structures of horny scales are soft keratin. In the center of the scales instead of the kernel there is a bubble of air.
The cementing substance connecting the most surface flakes of the horn layer is destroyed by a lipolytic enzyme cholesterinsulfatase secreted by intapidermal macrophages. Therefore, scales are subjected desquamations (Sewage).
The horny layer on the palm surface reaches a thickness of 600 μm. This layer has a large density, low thermal conductivity and impermeability for water, bacteria and toxins.
^ The process of organization (keratinization) It lasts 3-4 weeks. It involves keratin filaments and fibrils, keratinosomes, desplaomomy, cementing substance, intapidermal macrophages (Langerhans cells), which secrete:
1) the growth factor of the epithelium stimulating the division of keratinocytes;
2) Calelons overwhelming keratinocyte division;
3) cholesterolfatase, splitting the lipids of the cementing substance, as a result of which there is a loss of surface scales.
The intensity of the orog increases in mechanical exposure to the skin, with a lack of vitamin A or excess of cortisol (hormone of the adrenal cortex).
Terminal bronchioles (TB) They have the same structure as pre-serinal bronchiols, but they are less in diameter and the walls are more subtle (Fig. 1). Terminal bronchiola is divided into two or three respiratory bronchioles (RB), in the final segments of which alveoli appear (a). Each respiratory bronchiola is divided into two or three alveolar strokes (ah), with which together forms pulmonary acinus (LA). Many alveoli opens in alveolar moves.
Mucous membrane bronchioles It consists of a single-layer cubic epithelium (E) and a very fine one's own plate. In the primary department respiratory bronchioles Smooth muscle fibers (c) of the muscular shell (MO) are separated from each other, so the muscular shell no longer looks the only formation. The number of smooth muscle beams sharply decreases to the place of branch respiratory bronchioles On alveolar moves, ultimately remaining only in the form of smooth muscle rings (k) between alveoli respiratory bronchioles and around the alveolar holes along the alveolar strokes. Smooth muscular rings are located in pins-shaped thickening on the free edges of alveolar partitions (al).
Reducing the smooth muscles of alveoli and air conductive paths can cause serious asthmatic symptoms.
In fig. 1 also shows the places of anastomoses of the pulmonary artery system (LA) with the system of branches of the bronchial artery (BA). Both systems are located in an adventitious shell (AO) bronchiole. The lung artery branch gives smaller vessels, which then form the extensive capillary network (CAP) around the breathable bronchiole and alveolar strokes. The final branches of the bronchial artery (shown by the arrow) fall into this network.
Epithelium (E) Prederminal Bronchiole (Fig. 2) is represented by epithelocytes from low-rotratic to cubic form with semicircular cells (RK) and Clara cells (CC), located in the baseal membrane (BM). The epithelium is becoming flattened to the end segment of respiratory bronchioles with the advent of the first alveoli.
Cells make up the main part of the cells. They have an elliptical core with a small nuclear fuel, a Golgi complex, a bit of a granular endoplasmic network tank, lysosomes, large mitochondria and several residual calves. Cells are carried on the apical end several microvones and cynicilli (K), whose oscillations are directed towards intra-light bronchi.
Clara cells (QC) are luxurious cells with a convex apical pole, an elongated core, a plurality of large mitochondria, well-developed Golgi complex and subnumber Ergastoplasm, containing many free ribosomes. In the outgower cytoplasm there is a minor number of tubes, and a granular endoplasmic network surrounded by electron-dense granules (g), which originated from the Golgi complex and smooth endoplasmic tubes. Secretory granules contain a mixture of glycosaminoglycans and cholesterol, which released on the epithelial surface form, probably the protective layer.
Fig. 3. It corresponds to the site of the beginning of the alveolar stroke, indicated by a white arrow in Fig. 1. B. terminal and respiratory bronchioles The epithelium gradually becomes cuboid, the number of semicircle cells (RK) decreases and the number of Clara cells (QC) increases. IN primary departments The moves or alveoli respiratory bronchiol epithelium becomes a single-layer flat, formed by extremely flat alveolar cells I type (AK I) and cuboid alveolar cells of the type (AK II). The capillary network (CAP) is located directly under this epithelial layer.
Protruding outside plane slice group of smooth muscle cells (MK) forms a muscular ring around the beginning
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Bronchiol, entering the luxury, gives rise to numerous twigs, which, like a tree, diverge to all parts of the slices. Due to the fact that bronchioles, as well as intra-robbing glands, lie inside the Parenhima of Polek, they are attached from all sides to the elastic tissue similar to the sponge containing the airspaces in which gas exchange occurs (Fig. 23 - 15). Therefore, when inhaling, they are not inclined to fall, moreover, they are tensile throughout their circumference due to the stretching of elastic fibers of the surrounding spongy fabric.
Fig. 23 - 13. The scheme of the structure of the lung slices, the base pointing to Plegre.
For clarity, the size of bronchioles and airways, as well as blood and lymphatic vessels increased. To make it easier to trace the course of blood and lymphatic vessels, the ones are not shown on the right, and the left is the second.
1 - Top, 2 - bronchiol, 3 - air, 4 - pulmonary vein, 5 - Interlimolar partition, 6 - Respiratory bronchiola, 7 - pleura, 8 - alveoli, 9 - Alveolar stroke, 10 - lymphatic vessel, 11 - pulmonary artery.
Therefore, in order to lumeitive bronchiol remained open, there is no need for cartilage rings or plates located in their wall. They differ from the bronchi also by the fact that there are no glands in their walls. Indeed, they are located so close to the plots where gas exchange is carried out, which if they had a secret released by the glands, he could sueple in these sites. In addition, the epithelial liner bronchiol has a smaller thickness than in bronchi. Cylindrical eyelant cells predominate in larger branches, but between them are scattered without ciliations (Fig. 23 - 14). These higher cells are sometimes called Clara cells. The peculiarity of these cells is the abundance of mitochondria (in some species), and between the core and the surface through which the secretion of the secret is carried out, there is a very well-developed smooth endoplasmic reticulum. These cells are characterized by high metabolic activity. However, the function of their serous secret is still not fixed. IN finite branches Bronchioles are high cubic cells without cilia. Thus, the walls of bronchiole (Fig. 23 - 12) consist of an epithelium that lies on a thin elastic proper plate of the mucous membrane, and this shell in turn is surrounded by a muscular shell, which was previously described in relation to bronchi. Muscular fabric is located on the connecting, which performs the reference function (Fig. 23 - 12).
Order bronchiole. After bronchiol, called preterminal, penetrates the slicker, it gives branches, known as the terminal bronchiol, the number of which varies depending on the size of the slices. Usually there are from 3 to 7 terminal bronchioles.
The next order bronchioles arising from terminal are called respiratory bronchioles (Fig. 23 - 13 and 23 - 15). They were named because, as these bronchioles are branched down and continueing them in the parenchyma of the lung in their walls, an increasing amount of thin, containing air of the protrusion appears. These small bubbles are surrounded by capillary networks forming thin plexuses, which will be described below. Between the blood, in the capillaries of the wall of these protruding, and the air inside them is gas exchange.
Fig. 23 - 14. Electronic micrograph, showing cells of the mucous membrane of small bronchioles from light mouse 6000 (from the kind permission of A. collet).
Among the college epithelial cells (1) there is a Clare Clare (2). Number numerous mitochondria and well-developed smooth endoplasmic reticulum, especially under the apical surface. Asterisks marked the basal membrane of the epithelium. As located below its own plate, the mucous membranes are smooth muscle cells (3) and connective tissue fibroblasts (4). At the top of the left - the lumen of bronchioles.
Since gas exchange is carried out in the protrusion of the walls of these bronchiol, the latter and were named respiratory bronchioles. The free ends of respiratory bronchioles are somewhat expanded and opened in the so-called alveolar moves.
Respiratory department Dolk- Alveolar moves,
Alveolar bags and alveoli
Before we begin the consideration of alveolar strokes, in which respiratory bronchiols open, it is useful to emphasize that bronchi and bronchioles - tubes that have their own walls, and their main function is to carry out air to the respiratory department of the poles and the air lead from it. Terms that we will now use, describing how the air is carried out in all parts of the respiratory department of the Solk (Alveolar moves, alveolar bags and alveoli) are not related to formations having their own wall, but to the spaces of various orders and forms that are located in Elastic tissue, similar to a sponge and containing numerous capillary networks (Fig. 23 - 13 and 23 - 15). 
Fig. 23 - 15. Microfotography of a light little child (small increase).
Respiratory bronchiola (1) fell into a longitudinal section, and it can be seen as it opens in two alveolar strokes (2). Asterisks marked alveolar bags. The latter, in turn, open into rounded airspaces, called alveoli.
Alveolar moves, alveolar bags and alveoli contain air, which is constantly updated. This air is closely in close contact with the capillaries in the walls of spongy fabric separating this piece of light into space, and since air and blood turn out to be separated only by thin tissue films through which diffusion easily occurs, an effective functional device is created that ensures carbon dioxide and The absorption of oxygen as the blood moves along the capillary networks of this part of the lung.
Alveolar moves, alveolar bags and alveoli. Spaces where respiratory bronchiols are opened directly, have the form of long branching "corridors", in the course of which there are numerous " open doors»Two main sizes. Corridors are called alveolar strokes (Fig. 23 - 15). Larger open doors are communicated with the spaces in the form of rotunda, called alveolar bags, which are marked in Fig. 23 - 15 asterisks. The peripheral zone of each bag having the type of rotunda is separated by departing inside by spon-shaped partitions on a series of cells that open in the central part of the bag. Cells are alveoli. It is estimated that in the lungs of an adult there is about 300 million alveoli, forming a common surface of about 70-80 m2, which contacts the air contained in them.
Before you start a description of the histological structure of the walls separating some airspaces from others, we describe briefly structural units of the respiratory department, which are smaller than the slices, sizes - they are important for understanding some pathological processes In the lungs.
Structural units inside slices. As already noted, bronchi be branched, forming ultimately bronchiols, which are included in the structural units of lung, called slices. At the same time, there is no general agreement on how to call structural units in which branches arising from the subsequent division of bronchioles in the slices. The exception in this respect is the unit of light, to which terminal bronchiola is suitable, this unit is now often called acinus. Millard (MILLARD) believes that acinus is the most important structural unit with which it has to deal with pathology. For structural units located more distally, the standard names are absent, however, as Barri believes, they should be denoted in accordance with the "tubes" suitable. Thus, the structural unit to which respiratory bronchiogen is suitable, can be called a respiratory bronchiolar unit, and the structural unit, which serves the alveolar stroke (DUCTUS), is a duktal unit.
Structure of the walls respiratory tract (mainly by Von Hayek)
The walls of the trachea and bronchi consist of three main layers: the mucous membrane, the submembratus and fiber-cartilaginous layer, which also includes smooth muscles.
The mucous membrane is formed by a falselylastic camber epithelium. The surface layer mainly consists of ciliary cells. Among them are scattered glazing cells secreting mucus. For the most part, glassia cells are surrounded by ciliary and their number decreases with a decrease in bronchial caliber. Under the surface layer of cells in large bronchops, another 2-3 rows of cuboid intermediate cells are located, the number of which is gradually decreased to the periphery, so that only a number of ciliary cells with single glass-shaped cells remain in bronchioles. The mucous membrane is selected outside the basal membrane formed by bunches of intertwined fibers. On the spur of the tracheal bifurcation and often in the underlying bifurcations area, the emergency epithelium is replaced by a multi-layer flat.
In the mucous membrane there are intercellular slits that may contain lymphocytes, leukocytes, fat cells, as well as, especially near bifurcation, rounded, slightly painted cells, which may be sensitive receptors. The mucous membrane is often located longitudinal folds, the thickness of which is probably partially dependent on the tone of the bronchial muscles.
The submucosal layer is thicker under the folds of the mucous membrane, and in the trachea and large bronchops - in the area of \u200b\u200bthe rear wall, between the edges of the cartilaginous rings. In the sublifted layer, the capillary network is directly in the basal membrane, while the pre- and post-topicular vessels lie in deeper layers, between elastic fibers. Bundles of elastic fibers are located mainly longitudinally, in the course of folds of the mucous membrane, thin, strata, although they are also associated with the mucous membrane, cartilage and with circular elastic fibers of the fiber-cartilating layer. In bronchioles, elastic fibers penetrate out and are connected to the alveoli elastic cloth.
The mucous glands occur throughout the trachea to the smallest bronchi and are especially numerous in the middle caliber bronchi. In large bronchops, they are located in the sublifting layer between the mucous membrane and cartilage, often penetrating out through the slots in the carte. Often they lie extrampuscularly, and their ducts proceed to the muscles and can even penetrate through fibrous layers in peribroscial connective tissue. The mucous glands usually have a sausage shape with a duct open at one end and passing perpendicular to the long axis of bronchus, emptying the surface of its mucous membrane. The size of the glands is very variable, and the largest of them reaches 1 mm in length. The epithelium of the mucous gland glazed glasses with different amounts of glassoid cells. In the muscular layer of bronchi, the ducts can become ampuloids, they can surround lymphoid fabric. Some cells of the mucous gland gland are grainy and presumably secrete the serous fluid, although Florey and Sotr. Based on histochemical studies, this phenomenon is deceptive and it is believed that in most cases these cells are likely to secrete mucus.
In the trachea and large bronchops, up to 4-5 divisions of segmentar bronchi, cartilage have a semicircuit form, sometimes the shape of the horseshoe, being unclipped from behind. This rear "membrane" part of the bronchi is formed outside the fibrous plate, which goes in the longitudinal direction between cartilage and connecting their ends.
The bifurcations of the bronchi and trachea are marked by cartilage spurs, the edge of which is bent in relation to the trachea. In smaller bronchops, the cartilage is broken down on uneven records, all rarely occurring along the downward branches bronchial treeuntil they disappear completely at the level of bronchiol.
In the trachea, smooth muscles join the ends of the cartilage, being knutut from the fibrous plate. When cutting muscles, the cartridge ends converge, resulting in invagination of the rear section of the mucous membrane in the lumen of the trachea. As the bronchial muscle branches are designed, the kleri on the inner surface of the cartilage is increasing until the rings are purchased. In those bronchops in which cartilages are no longer arranged circularly, the bronchial muscles have a more longitudinal direction and the type of spiral, so when they are reduced, the observation of the lumen and shortening of the bronchi occurs. In smaller bronchops, the muscles are separated from the cartilage with a loose vascular layer with numerous branches of bronchial artery, veins and lymphatic vessels. In bronchioles, muscles tend to dive into the surrounding pulmonary fabric. In relation to the thickness of the bronchial wall, the most developed muscular layer is in bronchioles. The extramascular venous network ends at the level of bronchiole, where the fibrous layer and the mucous membrane merge.
Bronchi is surrounded by peribroscial tissue, consisting mainly of loose connective tissue, which does not hinder the movement of bronchi, which goes into the near-sophisticated tissue of pulmonary arteries and large veins. It contains bronchial arteries and veins, nerves, lymphatic vessels, lymphoid and adipose tissue. In peribroscial tissue, dust often postponed, especially in the field of bronchial dieting angles, where the lymphoid fabric surrounds macrophages that swallowed dust. Bronchiols do not contain or cartilage or mucous glands. They are formed by one layer of wildlife epithelium with single glassworm cells. Terminal bronchiola is the most remote and has a complete epithelial diller. Respiratory bronchiola is partly formed by alveoli opening in it.
