Boundaries of the lungs and pleura. Pleural sinus
Respiratory system. General information………………………………………………………...4
Nose………………………………………………………………………………………..5
Larynx………………………………………………………………………………...7
Trachea………………………………………………………………………………...13
Main bronchi………………………………………………………...15
Lung…………………………………………………………………………………...15
Pleura………………………………………………………………………………...21
Mediastinum………………………………………………………………………………...24
Urinary system. Male reproductive system. Female reproductive system. General information………………………………………………………..………………….26
Urinary organs…………………………………………………………………………………27
Kidney………………………………………………………………………………28
Ureter………………………………………………………………………………..33
Bladder………………………………………………………..35
Female urethra……………………………………37
Male genital organs………………………………………………………37
Internal male genital organs…………………………………..37
External male genitalia……………………………………44
Female genital organs……………………………………………………….48
Internal female genital organs…………………………………..48
External female genitalia…………………………………….53
Crotch………………………………………………………………………………..55
Questions of test self-control of knowledge……………………………………...59
Situational tasks………………………………………………………...74
Standards of correct answers……………………………………………………………..83
Respiratory system
General information
Respiratory system, sistema respiratorium ensures gas exchange between inhaled air and blood, and is also the main part of the voice production apparatus. The respiratory system consists of the respiratory tract and the respiratory organ itself – the lungs.
The airways are hollow organs that conduct air to the pulmonary alveoli. There are upper respiratory tracts - the external nose, nasal cavity and pharynx, and lower respiratory tracts - larynx, trachea, bronchi.
Development. During the process of phylogenesis, the respiratory organs of terrestrial vertebrates are formed in the form of an outgrowth of the intestinal tube. The nasal cavity is separated in the class of reptiles from the oral cavity as a result of the formation of the palate. These same processes are repeated in the development of the human embryo. The formation of the palate occurs in the 2nd month of the embryonic period. At the same time, a nasal septum is formed, which divides the nasal cavity into right and left parts. The external nose is formed from the median, medial and lateral nasal protrusions on the fetal face. The larynx and trachea are formed on the ventral wall of the primary pharynx in the form of a laryngeal-tracheal groove, which is separated from the primary esophagus and forms the laryngeal-tracheal tube - the rudiment of the larynx and trachea. In the larynx primordium, laryngeal cartilages are formed from the cartilages of the III-IV branchial arches.
The distal end of the laryngeal-tracheal tube expands to form the pulmonary kidney. The latter is divided into the rudiments of the right and left main bronchi. By budding, lobar bronchi are formed first (3 in the right and 2 in the left lung), and then bronchi of the third and next orders. As a result, the bronchial tree is formed. The respiratory parenchyma of the lungs is formed from the mesenchyme that surrounds the bronchi. Serous pleural cavities form around the lungs. Starting from the 5th month of the intrauterine period, pulmonary alveoli are formed, and the lungs can provide breathing for the fetus outside the mother’s body.
There is a distinction between the external nose and the nasal cavity (internal nose).
External nose, nasus externus , (Greek – rhis, rhinos ) has:
1) root, radix nasi ;
2) backrest, backsum nasi ;
3) top, apex nasi ;
4) wings, alae nasi .
The lower edges of the wings of the nose limit the openings leading from the outside into the nasal cavity - the nostrils, nares. The bony basis of the external nose is formed by the nasal bones and the frontal processes of the upper jaws. The bony skeleton is supplemented by nasal cartilages, cartilagines nasi:
A) lateral nasal cartilage, cartilage nasi lateralis ;
b) large and small cartilages of the wings,cartilagines alares major et minores ;
V) accessory nasal cartilages, cartilagines nasalis accesoriae ;
G) nasal septum cartilage, cartilage septi nasi .
The external nose is a specific feature of humans; it is not expressed even in anthropoids. Nose shapes and sizes vary across race and ethnicity and are highly variable individually. The sizes are divided into large and small; by weight - thin and thick; in shape - narrow, wide, curved. The line of the back of the nose can be straight, convex (humpbacked nose) or concave (saddle nose). The base of the nose can be horizontal, raised (snub) or downturned.
Nasal cavity, cavitas nasi , steam room, separated nasal septum, septum nasi . In the partition there are:
1) the membranous part, which is adjacent to the nostrils;
2) the cartilaginous part, the basis of which is the cartilage of the nasal septum;
3) the bone part, which consists of a perpendicular plate of the ethmoid bone, vomer, sphenoid and palatine ridges.
The part of the nasal cavity adjacent to the nostrils is called vestibule of the nose, vestibulum nasi ; it is separated from the nasal cavity proper protruding threshold, limen nasi ; covered with skin that contains sweat and sebaceous hair glands - vibrissae. The nasal cavity itself is divided into two parts - olfactory, pars olfactoria , And respiratory, pars respiratoria . The olfactory region occupies the superior turbinate and the upper part of the nasal septum. This is where the olfactory receptor cells are located and where the olfactory nerves begin. The respiratory region covers the rest of the nasal cavity. It is lined with ciliated epithelium and contains numerous serous and mucous glands, blood and lymphatic vessels. In the submucosa of the middle and inferior turbinates there are cavernous venous plexuses; damage to the mucous membrane in this part of the nasal cavity can lead to severe nosebleeds.
The mucous membrane of the nasal cavity continues into the mucous membrane lining the paranasal sinuses, which open into the nasal passages. In newborns, the nasal cavity is low and narrow, the nasal turbinates are thick, the nasal passages are short and narrow; Of the paranasal sinuses, only the maxillary sinus is expressed; the rest are in their infancy and form in childhood. In old age, atrophy of the mucous membrane and its glands occurs.
Functions of the nasal cavity:
1) conducting air during breathing;
2) humidification of inhaled air;
3) purification of air from foreign particles.
Anomalies of the external nose and nasal cavity
1. Arinia – congenital absence of the nose.
2. Dirynia - doubling of the nose, most often its apex is split.
3. Deviation of the nasal septum. Leads to difficulty in nasal breathing and the outflow of fluid from the paranasal sinuses.
4. Choanal atresia. Makes nasal breathing impossible, observed in some hereditary congenital malformations (syndromes).
Larynx
Larynx, larynx, belongs to the lower respiratory tract and is a voice-forming organ.
Topography
Holotopia: The larynx is located in the middle part of the anterior region of the neck; it protrudes under the skin, forming laryngeal prominence, prominentia laryngis , more pronounced in men (Adam's apple).
Skeletotopia: in adults, the larynx is located at the level of the IV-VI cervical vertebrae.
Syntopy: at the top the larynx is suspended from the hyoid bone, at the bottom it continues into the trachea. The thyroid gland lies in front and to the sides of it. The main neurovascular bundle of the neck (carotid arteries, internal jugular vein and vagus nerve) runs laterally. In front, the larynx is not completely covered by the sublingual muscles with the pretracheal plate of the cervical fascia. The laryngeal part of the pharynx is located at the back. Here is entrance to the larynx, aditus laryngis ; it is limited by the epiglottis and two folds of the mucous membrane that extend from the epiglottis downward and posteriorly. At the posterior end of these folds protrudes horn-shaped tubercle, tuberculum corniculatum , And wedge-shaped tubercle, tuberculum cuneiforme , which correspond to the cartilages of the same name located in the thickness of the fold.
From the upper edge of the epiglottis, the unpaired median and paired lateral glossoepiglottic folds, plicae glossoepiglotticae mediana et laterales, go to the root of the tongue. They limit the fossae of the epiglottis, valleculae epiglotticae.
Structure of the larynx
The skeleton of the larynx is formed by unpaired and paired cartilages.
Thyroid cartilage, cartilago thyroidea , unpaired, hyaline. It consists of two plates that converge at an angle to each other. For men this angle is acute. At the junction of the plates on top there is tenderloin, incisura thyroidea . From the rear edge of each plate, the upper horns, cornu superior, are long and narrow, and the lower horns, cornu inferior, are short and wide. The inferior horns connect to the cricoid cartilage. Visible on the outer surface of the thyroid cartilage oblique line, linea oblique , – the place of attachment of the sternothyroid and thyrohyoid muscles.
Cricoid cartilage, cartilago cricoidea , unpaired, hyaline, lies at the base of the larynx. Its front part forms an arc, the back part – a plate. On the sides of the plate there is a paired articular surface for articulation with the thyroid cartilage, and in its upper part there is a paired surface for articulation with the arytenoid cartilages.
Arytenoid cartilage, cartilago arytenoidea , paired, hyaline, pyramid-shaped. It has a top and a base. At the base there is an articular surface for articulation with the cricoid cartilage. Two branches extend from the base:
2) muscular process, processus muscularis , - the place of attachment of the muscles of the larynx, is built of hyaline cartilage.
Epiglottis, epiglottis , unpaired, elastic. At the bottom it narrows, forming stalk, petiolus .
Wedge-shaped and cornicular cartilages, cartilagines cuneiformis et corticulatae , paired, elastic, located above the apex of the arytenoid cartilages.
The cartilages of the larynx are connected to each other and to neighboring formations through ligaments, membranes and joints.
Between the larynx and the hyoid bone is located thyrohyoid membrane, membrana thyrohyoidea , in which the median and paired lateral thyrohyoid ligaments are distinguished. The latter arise from the superior horns of the thyroid cartilage. The epiglottis fixes two ligaments:
1) sublingual-epiglottic, lig. hyoepiglotticum;
2) thyroid-epiglottic, lig. thyroepiglotticum .
The thyroid cartilage is connected to the arch of the cricoid cartilage through cricothyroid ligament, lig. cricothyroideum . The cricoid cartilage connects to the trachea cricotracheal ligament, lig. cricatracheale . Located under the mucous membrane fibro-elastic membrane of the larynx, membrana fibroelastica laryngis ; in the upper part of the larynx it forms quadrangular membrane, membrane quadrangularis , and in the lower part – elastic cone, cone elasticus . The lower edge of the quadrangular membrane forms a steam room vestibular ligament, lig. vestibulare , and the upper edge of the elastic cone is the steam room vocal cord, lig. vocal , which is stretched between the angle of the thyroid cartilage and the vocal process of the arytenoid cartilage.
The joints of the larynx are paired, combined:
1. cricothyroid joint, art. cricothyroidea , formed by the articulation of the articular surfaces of the cricoid cartilage with the lower horns of the thyroid cartilage. Has one transverse axis of rotation. When the thyroid cartilage moves forward, the vocal folds lengthen and tighten, and when it moves backward, they relax.
2. Cricoarytenoid joint, art. cricoarytenoidea , formed by the articulation of the articular surfaces of the cricoid cartilage with the articular surfaces of the arytenoid cartilages. Has a vertical axis of rotation. When the arytenoid processes rotate inward, the vocal cords come closer together (the glottis narrows), and when they rotate outward, they move away from each other (the glottis widens).
The muscles of the larynx are striated, voluntary, they move the cartilages of the larynx relative to each other, change the size of the glottis and the tension of the vocal cords (folds). There are external and internal muscles of the larynx.
According to function, the muscles of the larynx are divided into three groups.
A) lateral cricoarytenoid muscle, m. crycoarytenoideus lateralis.
Start: upper edge of the cricoid cartilage arch.
Attachment: muscular process of the arytenoid cartilage.
Function: rotates the arytenoid cartilage around a vertical axis; in this case, the vocal process moves medially and the vocal cords come closer together.
b) thyroarytenoid muscle , m. thyroarytenoideus .
Start: inner surface of the lamina of the thyroid cartilage.
Attachment: anterolateral surface of the arytenoid cartilage.
Function: similar to the previous muscle.
V) transverse arytenoid muscle, m. arytenoideus transversus.
G) oblique arytenoid muscle, m. arytenoideus obliquus .
Start and Attachment: posterior surfaces of the arytenoid cartilages.
Function: Both muscles bring the arytenoid cartilages closer to the midplane, promoting closure of the glottis.
d) aryepiglottic mouse, m. aryepiglotticus , is a continuation of the oblique arytenoid muscle, passes in the fold of the same name.
Function: narrows the entrance to the larynx and the vestibule of the larynx, pulls the epiglottis back and down, covering the entrance to the larynx when swallowing.
A) posterior cricoarytenoid , m. cricoarytenoideus posterior .
Start: posterior surface of the cricoid cartilage plate.
Attachment: muscular process of the arytenoid cartilage.
Function: rotates the arytenoid cartilage around a vertical axis, turning the vocal processes laterally, while the glottis expands.
A) cricothyroid muscle, m. cricothyroideus.
Start: arch of cricoid cartilage.
Attachment: the lower edge of the thyroid cartilage and its lower horn.
Function: tilts the thyroid edge forward, increasing the distance between it and the vocal process, while the vocal cords lengthen and stretch;
Start: inner surface of the thyroid cartilage.
Function: the muscle contains longitudinal, vertical, and oblique fibers. Longitudinal fibers shorten the vocal cord, vertical fibers strain it, and oblique fibers strain individual parts of the vocal cord.
Laryngeal cavity, cavitas laryngis , resembles an hourglass and is divided into three sections: the vestibule of the larynx, the interventricular part and the subglottic cavity.
Vestibule of the larynx, vestibulum laryngis , extends from the entrance to the larynx to the vestibular folds, which include the vestibular ligaments.
Interventricular part, pars interventricularis , located from the vestibule to the vocal folds, the narrowest place of the larynx, up to 1 cm high. Vocal folds, plicae vocals , contain in their posterior part the vocal processes of the arytenoid cartilages, and in the anterior part - the elastic vocal fold and vocal muscle. Both vocal folds limit the glottis, rima glottidis s. vocalis . It distinguishes the back - intercartilaginous part, pars intercartilaginea , and the front - intermembranous part, pars intermembranacea . Between the vestibular and vocal folds on each side there is a depression - ventricle of the larynx , ventriculus laryngis .
Subglottic cavity, cavitas infraglottica , extends from the vocal folds to the beginning of the trachea. The mucous membrane of the larynx is lined with stratified ciliated epithelium. The exception is the vocal folds, which are covered with stratified squamous epithelium.
The function of the larynx as a respiratory and vocal organ. The muscles attached to the hyoid bone (supra- and hyoid) raise, lower, or fix the larynx. When swallowing, the larynx is raised by the action of the suprahyoid muscles, the root of the tongue moves posteriorly and presses on the epiglottis so that it covers the entrance to the larynx. This is facilitated by the contraction of the thyroepiglottic and aryepiglottic muscles.
With quiet breathing and whispering, the intermembranous part of the glottis is closed, and the intercartilaginous part is open in the form of a triangle by the action of the lateral cricoarytenoid muscle. During deep breathing, both parts of the glottis are opened in a diamond shape by the action of the posterior cricoarytenoid muscle. At the beginning of vocal production, the glottis closes and the vocal cords become tense. The flow of exhaled air causes vibrations in the vocal folds, resulting in sound waves. The strength of sound is determined by the strength of the air flow, which depends on the lumen of the glottis, and the timbre of the voice is determined by the frequency of vibration of the vocal folds. The installation of the vocal folds is carried out by the cricothyroid muscle and the muscles attached to the muscular process, and more precisely, it is modeled by the vocal muscle.
The resonators of sound produced by the vocal apparatus are the pharynx, oral and nasal cavities, and paranasal sinuses. The pitch of the voice depends on the individual structural features of the sound resonators. Due to the position of the larynx in a person, the sounding air flow is directed to the speech organs - palate, tongue, teeth and lips. When coughing, a closed glottis opens with expiratory impulses.
Age characteristics. In newborns, the larynx is located at the level of the II-IV cervical vertebrae. The epiglottis touches the uvula. The larynx is short and wide, its cavity is funnel-shaped, and there is no laryngeal prominence. The vocal folds are short, the ventricles of the larynx are shallow. Rapid growth of the larynx occurs in children 3 years old, at 5-7 years old, and especially during puberty. At 12-13 years old, the length of the vocal folds in girls increases by 1/3, and in boys at 13-15 years old, by 2/3. This causes a mutation (fracture) of the voice in boys. In men, growth of the vocal folds continues until the age of 30. Gender differences in voice are due to the greater length of the vocal folds and glottis in men. In old age, the cartilage of the larynx becomes calcified, the vocal cords become less elastic, which leads to a change in voice.
Anomalies of the larynx
1. Atresia, stenosis.
2. Formation of septa in the laryngeal cavity.
3. Aplasia of the epiglottis. In this case, the entrance to the larynx is not closed.
4. Laryngeal-esophageal fistulas. They are formed when the laryngeal primordium is incompletely separated from the digestive tube.
Trachea
Trachea, trachea , (windpipe), - an unpaired tubular organ, serves to conduct air.
Topography
Holotopia: cervical part, pars cervicalis, is located in the lower part of the anterior cervical region; The thoracic part, pars thoracica, lies in the anterior part of the upper mediastinum.
Skeletotopia: in adults it begins at the level of the VI cervical vertebra and ends at the level of the V thoracic vertebra (2-3 rib), where it forms a bifurcation, bifurcatio tracheae , that is, it is divided into two main bronchi.
Syntopy: The thyroid gland is adjacent to the cervical part in front and on the sides, and the hypoglossal muscles are also located. There is a gap between the edges of the muscles in the midline, where the trachea is covered only by the pretracheal plate of the cervical fascia. Between this plate and the trachea there is a pretracheal cellular space that communicates with the mediastinum. The thoracic part of the trachea borders in front with the aortic arch, brachiocephalic trunk, left brachiocephalic vein, left common carotid artery, thymus gland, laterally with the mediastinal pleura, behind with the esophagus throughout the trachea.
Structure of the trachea
The tracheal skeleton is 16-20 hyaline half rings, cartilagines tracheales . They are connected to each other by fibrous annular ligaments, ligg. anularia . At the top, the trachea is connected to the cricoid cartilage of the larynx by the cricotracheal ligament. The cartilages of the trachea form the anterior and lateral walls, the posterior wall of the trachea - membranous, paries membranaceus , contains connective tissue, circular and longitudinal bundles of smooth muscles. The tracheal cavity is lined with a mucous membrane with stratified ciliated epithelium; it contains branched mucous glands and lymphatic follicles. Externally, the trachea is covered with an adventitial membrane.
Age characteristics. In newborns, the trachea begins at the level of the IV cervical vertebra, and its bifurcation projects to the III thoracic vertebra. Tracheal cartilages and glands are poorly developed. The growth of the trachea occurs most intensively in the first 6 months after birth and during puberty. The final position of the trachea is established after 7 years. In old age, atrophy of the mucous membrane, glands, lymphoid tissue, and calcification of cartilage are observed.
Tracheal anomalies
1. Atresia and stenosis.
2. Deformation and splitting of cartilage.
3. Tracheo-esophageal cartilages.
Main bronchi
Main bronchi, right and left, bronchi principales dexter et sinister , depart from the bifurcation of the trachea and go to the gates of the lungs. The right main bronchus is more vertical, wider and shorter than the left bronchus. The right bronchus consists of 6-8 cartilaginous half-rings, the left - 9-12 half-rings. Above the left bronchus lie the aortic arch and the pulmonary artery, below and anteriorly there are two pulmonary veins. The right bronchus is surrounded by the azygos vein from above, and the pulmonary artery and pulmonary veins pass below. The mucous membrane of the bronchi, like the trachea, is lined with stratified ciliated epithelium and contains mucous glands and lymphatic follicles. At the hilum of the lungs, the main bronchi are divided into lobar bronchi. Further branching of the bronchi occurs inside the lungs. The main bronchi and their branches form the bronchial tree. Its structure will be discussed when describing the lungs.
Lung
Lung, pulmo (Greek pneumonia ), is the main organ of gas exchange. The right and left lungs are located in the chest cavity, occupying its lateral sections together with their serous membrane - the pleura. Each lung has top, apex pulmonis , And base, basis pulmonis . The lung has three surfaces:
1) costal surface, facies costalis , adjacent to the ribs;
2) diaphragmatic surface, facies diaphragmatica , concave, facing the diaphragm;
3) medial surface, facies medialis . The medial surface in its anterior part borders mediastinum – pars mediastinalis , and in its rear part – with spinal column, pars vertebralis .
Separates the costal and medial surfaces anterior edge of the lung, margo anterior ; in the left lung the anterior edge forms heart tenderloin, incisura cardiaca , which is bounded below uvula of the lung, lingula pulmonis . The costal and medial surfaces are separated from the diaphragmatic surface the lower edge of the lung, margo inferior . Each lung is divided into lobes by interlobar fissures, fissurae interlobares. Oblique slot, fissura obliqua , begins on each lung 6-7 cm below the apex, at the level of the III thoracic vertebra, separating the upper from the lower lung lobes, lobus pulmonissuperior et inferior . Horizontal slot , fissura horizontalis , present only in the right lung, located at the level of the IV rib, and separates the upper lobe from the middle lobe, lobus medius . The horizontal gap is often not expressed throughout its entire length and may be completely absent.
The right lung has three lobes - upper, middle and lower, and the left lung has two lobes - upper and lower. Each lobe of the lungs is divided into bronchopulmonary segments, which are the anatomical and surgical unit of the lung. Bronchopulmonary segment- this is a section of lung tissue surrounded by a connective tissue membrane, consisting of individual lobules and ventilated by a segmental bronchus. The base of the segment faces the surface of the lung, and the apex faces the root of the lung. In the center of the segment there are a segmental bronchus and a segmental branch of the pulmonary artery, and in the connective tissue between the segments there are pulmonary veins. The right lung consists of 10 bronchopulmonary segments - 3 in the upper lobe (apical, anterior, posterior), 2 in the middle lobe (lateral, medial), 5 in the lower lobe (upper, anterior basal, medial basal, lateral basal, posterior basal). The left lung has 9 segments - 5 in the upper lobe (apical, anterior, posterior, superior lingular and inferior lingular) and 4 in the lower lobe (superior, anterior basal, lateral basal and posterior basal).
On the medial surface of each lung at the level of the V thoracic vertebra and II-III ribs are located gate of the lungs , hilum pulmonis . Gate of the lungs- this is the place where the root of the lung enters, radix pulmonis, formed by a bronchus, vessels and nerves (main bronchus, pulmonary arteries and veins, lymphatic vessels, nerves). In the right lung, the bronchus occupies the highest and dorsal position; The pulmonary artery is located lower and more ventral; even lower and more ventral are the pulmonary veins (PAV). In the left lung, the pulmonary artery is located highest, lower and dorsal is the bronchus, and even lower and ventral are the pulmonary veins (PV).
Bronchial tree, arbor bronchialis , forms the basis of the lung and is formed by the branching of the bronchus from the main bronchus to the terminal bronchioles (XVI-XVIII orders of branching), in which air movement occurs during breathing (Fig. 1).
The total cross-section of the respiratory tract increases from the main bronchus to the bronchioles by 6,700 times, so as air moves during inhalation, the speed of the air flow decreases many times. The main bronchi (1st order) at the gates of the lung are divided into lobar bronchi, btonchi lobares . These are the bronchi of the second order. The right lung has three lobar bronchi - upper, middle, lower. The right upper lobar bronchus lies above the pulmonary artery (epiarterial bronchus), all other lobar bronchi lie below the corresponding branches of the pulmonary artery (hypoarterial bronchi).
The lobar bronchi are divided into segmental bronchi(3 orders), bronchi segmentales , ventilating bronchopulmonary segments. Segmental bronchi are divided dichotomously (each into two) into smaller bronchi of 4-9 orders of branching; included in the lobules of the lung, these are lobular bronchi, bronchi lobulares . lobe of lung, lobules pulmonis, is a section of lung tissue limited by a connective tissue septum, with a diameter of about 1 cm. There are 800-1000 lobules in both lungs. The lobular bronchus, having entered the lung lobule, gives off 12-18 terminal bronchioles, bronchiole terminales . Bronchioles, unlike bronchi, do not have cartilage and glands in their walls. Terminal bronchioles have a diameter of 0.3-0.5 mm; smooth muscles are well developed in them, with the contraction of which the lumen of the bronchioles can decrease by 4 times. The mucous membrane of the bronchioles is lined with ciliated epithelium.
Each terminal bronchiole is divided into respiratory bronchioles, bronchiole respiratorii , on the walls of which pulmonary vesicles appear, or alveoli, alveolae pulmonales . The respiratory bronchioles form 3-4 orders of branching, after which they are radially divided into alveolar ducts, ductuli alveolares . The walls of the alveolar ducts and sacs consist of pulmonary alveoli with a diameter of 0.25-0.3 mm. The alveoli are separated by septa in which networks of blood capillaries are located. Through the wall of the alveoli and capillaries, exchange takes place between blood and alveolar air. The total number of alveoli in both lungs is about 300 million in an adult, and their surface is about 140 m2. Respiratory bronchioles, alveolar ducts and alveolar sacs with alveoli make up alveolar tree, or respiratory parenchyma of the lung. The functional and anatomical unit of the lung is considered acini. It is part of the alveolar tree into which one terminal bronchiole branches (Fig. 2). Each lung lobe contains 12-18 acini. The total number of branches of the bronchial and alveolar tree from the main bronchus to the alveolar sacs is 23-25 orders of magnitude in an adult.
The structure of the lung ensures that during respiratory movements there is a constant change of air in the alveoli and contact of alveolar air with blood. This is achieved by respiratory excursions of the chest, contraction of the respiratory muscles, contraction of the respiratory muscles, including the diaphragm, as well as the elastic properties of the lung tissue itself.
Age characteristics. The lungs of a non-breathing fetus differ from the lungs of a newborn baby in their specific gravity. In the fetus it is above one, and the lungs drown in water. The specific gravity of a breathing lung is 0.49, and it does not sink in water. The lower borders of the lungs in newborns and infants are located one rib lower than in adults. In the lungs, elastic tissue and interlobar septa are well developed, so the boundaries of the lobules are clearly visible on the surface of the lung.
After birth, lung capacity increases rapidly. The vital capacity of a newborn is 190 cm 3 , by the age of 5 it increases five times, by the age of 10 – ten times. Up to 7-8 years, new alveoli are formed and the number of branching orders of the alveolar tree increases. The dimensions of the alveoli are 0.05 mm in a newborn, 0.2 mm in an 8-year-old child, and 0.3 mm in an adult.
In old age and old age, atrophy of the mucous membrane of the bronchi, glands and lymphoid formations occurs, the cartilage in the walls of the bronchi becomes calcified, the elasticity of the connective tissue decreases, and ruptures of the interalveolar septa are observed.
Anomalies of the bronchi and lungs
1. Agenesis and aplasia of the main bronchus and lung.
2. Absence of one of the lobes of the lung along with the lobar bronchus.
3. Bronchial atresia with congenital atelectasis (collapse) of the corresponding part of the lung (lobe or segment).
4. Accessory lobes located outside the lung, not connected to the bronchial tree and not involved in gas exchange.
5. Unusual division of the lung into lobes in the absence of a horizontal fissure in the right lung or when the upper part of the lower lobe is separated by an additional fissure.
6. An abnormal lobe of the azygos vein, lobus venae azygos, is formed when the azygos vein passes through the apex of the right lung.
7. The origin of the right upper lobe bronchus directly from the trachea (tracheal bronchus).
8. Broncho-esophageal fistulas. They have the same origin as tracheal-esophageal fistulas.
9. Bronchopulmonary cysts are congenital dilatations of the bronchi (bronchiectasis) with liquid contents.
Pleura
Pleura, pleura , is the serous membrane of the lung, consisting of visceral and parietal plates. Visceral(pulmonary) pleura, pleura visceralis (pulmonalis), fuses with the lung tissue and extends into the interlobar fissures. Forms pulmonary ligament, lig. Pulmonale , which goes from the root of the lung to the diaphragm. It has villi that secrete serous fluid. This liquid adheres the visceral pleura to the parietal pleura, reduces friction of the surfaces of the lungs during breathing, and has bactericidal properties. At the root of the lung, the visceral pleura transforms into the parietal pleura.
parietal pleura, pleure parietalis , fuses with the walls of the chest cavity, it has microscopic openings (stomata), through which serous fluid is absorbed into the lymphatic capillaries.
The parietal pleura is topographically divided into three parts:
1) costal pleura, pleura costalis , covers the ribs and intercostal spaces;
2) diaphragmatic pleura, pleura diaphragmatica covers the diaphragm;
3) mediastinal pleura, pleura mediastinalis , goes in the sagittal cavity, limiting the mediastinum. Above the apex of the lung, the parietal pleura forms the pleural dome.
In places where one part of the parietal pleura transitions to another, depressions are formed - pleural sinuses, sinus pleuralis . These are reserve spaces into which the lungs enter when taking a deep breath. Serous fluid can also accumulate in them during inflammation of the pleura, when the processes of its formation or absorption are disrupted.
1. Costophrenic sinus, recessus costodiafragmaticus , paired, formed at the transition of the costal pleura to the mediastinal pleura, expressed on the left in the area of the cardiac notch of the lung.
2. Phrenic-mediastinal sinus, recessus phrenicomediastinalis , paired, located at the transition of the mediastinal pleura to the diaphragmatic one.
3. Costomedial sinus , recessus costomediastinalis , located at the point of transition of the costal pleura (in its anterior section) into the mediastinal; poorly expressed.
Pleural cavity, cavitas pleurae, - this is a slit-like space between two visceral or between two parietal layers of the pleura with a minimal amount of serous fluid.
Boundaries of the lungs and pleura
There are upper, anterior, lower and posterior borders of the lungs and pleura.
Upper the border is the same for the right and left lungs and the dome of the pleura is 2 cm above the collarbone or 3-4 cm above the first rib; posteriorly it is projected at the level of the spinous process of the VII cervical vertebra.
Front the border passes behind the sternoclavicular joint to the junction of the manubrium and the body of the sternum and from here descends along the sternum line to the cartilage of the VI rib on the right and the cartilage of the IV rib on the left. On the right, at the level of the cartilage of the sixth rib, the anterior border becomes the lower border.
On the left, the border of the lung runs horizontally behind the IV rib to the midclavicular line, and the border of the pleura is at the same level to the parasternal line. From here, the borders of the left lung and hymen descend vertically down to the VI rib, where they pass into their lower borders.
Two triangular spaces are formed between the anterior borders of the right and left pleura:
1) superior interpleural space field, area interpleurica superior , located behind the manubrium of the sternum, the thymus gland is located here;
2) inferior interpleural field, area interpleurica inferior , located behind the lower third of the sternum, here between the right and left pleura lies the heart with the pericardium.
The lower border of the right lung crosses the VI rib along the midclavicular line, the VII rib along the anterior axillary line, the VIII rib along the middle axillary line, the IX rib along the posterior axillary line, the X rib along the scapular line, and ends at the level of the neck of the XI rib along the paravertebral line (Table 1). The lower border of the left lung is basically the same as on the right, but approximately the width of the rib below (along the intercostal spaces). The lower border of the pleura corresponds to the junction of the costal pleura and the diaphragmatic pleura. On the left it is also located slightly lower than on the right, crossing the VII-XI intercostal spaces along the lines described above.
Table 1
Lower borders of the right lung and pleura
The discrepancy between the lower boundaries of the pleura and lungs is caused by the costophrenic sinuses. The lower borders of the lungs and pleura are individually variable. With a brachymorphic body type with a wide chest, they can be located higher than in people of a dolichomorphic type with a narrow, long chest.
Posterior border in both lungs it goes the same way. The posterior blunt edge of the organ is projected along the spinal column from the neck of the 11th rib to the head of the 2nd rib.
Mediastinum
Mediastinum, mediastinum , is a complex of organs located in the chest cavity between the right and left pleural cavities. In front it is limited by the sternum and costal cartilages; behind – thoracic vertebrae; on the right and left – mediastinal pleura; from below - the diaphragm. At the top, the mediastinum communicates with the neck region through the superior thoracic aperture.
The greatest clinical significance is the division of the mediastinum into front and back, mediastinum anterius et posterius . They are separated by a frontal plane, conventionally drawn through the trachea and roots of the lungs.
To the organs front The mediastinum includes the heart with the pericardial sac and the beginning of large vessels, the thymus gland, phrenic nerves, pericardial-phrenic vessels, internal thoracic blood vessels, and lymph nodes.
IN rear The mediastinum contains the esophagus, the thoracic part of the descending aorta, the thoracic lymphatic duct, the azygos and semi-gypsy veins, the right and left vagus and splanchnic nerves, sympathetic trunks, and lymph nodes.
There is another classification that involves dividing the mediastinum into upper and lower. The boundary between them is a conventional horizontal plane, passing in front through the junction of the manubrium with the body of the sternum, in the back - through the disc between the IV and V thoracic vertebrae, i.e. at the level of the tracheal bifurcation.
IN upper mediastinum, mediastinum superior located: the thymus gland, large pericardial vessels, vagus and phrenic nerves, sympathetic trunk, thoracic lymphatic duct, upper part of the thoracic esophagus.
In the lower mediastinum mediastinum inferior , in turn, the anterior, middle and posterior mediastinum are distinguished. The border between them runs along the anterior and posterior surfaces of the pericardial sac:
· anterior mediastinum, mediastinum anterior , contains fatty tissue and blood vessels;
· middle mediastinum,mediastinum medius , corresponds to the location of the heart with the pericardium, large pericardial vessels and roots of the lungs. The phrenic nerves also pass here, accompanied by the phrenic-pericardial vessels, and the lymph nodes of the lung root are located;
· posterior mediastinum, mediastinum posterior , contains the thoracic part of the descending aorta, azygos and semi-gypsy veins, right and left sympathetic trunks, vagus, splanchnic nerves, thoracic lymphatic duct, middle and lower parts of the thoracic esophagus, lymph nodes.
Pleura , pleura, being the serous membrane of the lung, it is divided into visceral (pulmonary) and parietal (parietal). Each lung is covered with pleura (pulmonary), which along the surface of the root passes into the parietal pleura.
^ Visceral (pulmonary) pleura,pleura visceralis (pulmonalls). Forms downward from the root of the lung pulmonary ligament,lig. pulmonary
Parietal (parietal) pleura,pleura parietalis, in each half of the chest cavity it forms a closed sac containing the right or left lung, covered with visceral pleura. Based on the position of the parts of the parietal pleura, it is divided into the costal, mediastinal and diaphragmatic pleura. Costal pleura, pleura costalis, covers the inner surface of the ribs and intercostal spaces and lies directly on the intrathoracic fascia. Mediastinal pleura, pleura mediastindlis, adjacent to the mediastinal organs on the lateral side, fused with the pericardium on the right and left; on the right it also borders with the superior vena cava and azygos vein, with the esophagus, on the left with the thoracic aorta.
Above, at the level of the superior aperture of the chest, the costal and mediastinal pleura pass into each other and form dome of pleura,cupula pleurae bounded on the lateral side by the scalene muscles. Anteriorly and medially to the dome of the pleura are the subclavian artery and vein. Above the dome of the pleura is the brachial plexus. Diaphragmatic pleura, pleura diaphragmatica, covers the muscular and tendon parts of the diaphragm, with the exception of its central sections. Between the parietal and visceral pleura there is pleural cavity,cavitas pleuralis.
^ Sinuses of the pleura. In the places where the costal pleura transitions into the diaphragmatic and mediastinal pleura, pleural sinuses,recessus pleurdles. These sinuses are the reserve spaces of the right and left pleural cavities.
Between the costal and diaphragmatic pleura there is costophrenic sinus , recessus costodiaphragmaticus. At the junction of the mediastinal pleura and the diaphragmatic pleura there is diaphragmomediastinal sinus , recessus phrenicomediastinalis. A less pronounced sinus (depression) is present at the place where the costal pleura (in its anterior section) transitions into the mediastinal pleura. Here it is formed costomedial sinus , recessus costomediastinalis.
^ Boundaries of the pleura. On the right is the anterior border of the right and left costal pleura from the dome of the pleura it descends behind the right sternoclavicular joint, then goes behind the manubrium to the middle of its connection with the body and from here descends behind the body of the sternum, located to the left of the midline, to the VI rib, where it goes to the right and passes into the lower border of the pleura. Lower limit The pleura on the right corresponds to the line of transition of the costal pleura into the diaphragmatic pleura.
^ On the left is the anterior border of the parietal pleura from the dome it goes, just like on the right, behind the sternoclavicular joint (left). Then it is directed behind the manubrium and the body of the sternum down to the level of the cartilage of the IV rib, located closer to the left edge of the sternum; here, deviating laterally and downwards, it crosses the left edge of the sternum and descends near it to the cartilage of the VI rib, where it passes into the lower border of the pleura. Lower border of the costal pleura on the left is located slightly lower than on the right side. In the back, as well as on the right, at the level of the 12th rib it becomes the posterior border. Posterior pleural border corresponds to the posterior line of transition of the costal pleura into the mediastinal pleura.
Anatomy of the medulla oblongata. Position of nuclei and pathways in the medulla oblongata.
Diamond brain
The medulla oblongata, myelencephalon, medulla oblongata, is a direct continuation of the spinal cord into the brain stem and is part of the rhomboid cord. It combines the structural features of the spinal cord and the initial part of the brain, which justifies its name muelencerhalon. Medulla oblongata has the appearance of a bulb, bulbus cerebri (hence the term “bulbar disorders”); The upper widened end borders the bridge, and the lower border serves as the exit point for the roots of the first pair of cervical nerves or the level of the greater foramen of the occipital bone.
1. On the anterior (ventral) surface of the medulla oblongata, the fissura mediana anterior runs along the midline, forming a continuation of the spinal cord groove of the same name. On either side of it there are two longitudinal strands - pyramids, pyramides medullae oblongatae, which seem to continue into the anterior cords of the spinal cord. The bundles of nerve fibers that make up the pyramid are partly
intersect in the depths of the fissura mediana anterior with similar fibers of the opposite side - decussatio pyramidum, after which they descend in the lateral cord on the other side of the spinal cord - tract us corticosrinalis (ruramidalis) lateralis, partly remain uncrossed and descend in the anterior cord of the spinal cord on their side tractus corticosrinalis ( ruramidalis) anterior.
Lateral to the pyramid lies an oval elevation - olive, which is separated from the pyramid by a groove, sulcus anterolateralis.
2. On the posterior (dorsal) surface of the medulla oblongata stretches the sulcus medianus posterior - a direct continuation of the spinal cord groove of the same name. On its sides lie the posterior funiculi, limited laterally on both sides by a weakly pronounced sulcus posterolateralis. In the upward direction, the posterior funiculi diverge to the sides and go to the cerebellum, entering the composition of its lower legs, redunculi cerebellares inferiores, bordering the rhomboid fossa from below. Each posterior cord is divided at
with the help of the intermediate groove on the medial, fasciculus gracilis, and lateral, fasciculus cuneatus. At the lower corner of the rhomboid fossa, the thin and wedge-shaped bundles acquire thickenings: tuberculum gracilis and tuberculum cuneatum. These thickenings are caused by the nuclei of gray matter, the nucleus gracilis and the nucleus cuneatus, which are related to the bundles. In these nuclei the ascending cords passing through the dorsal funiculi end
spinal cord fibers (thin and wedge-shaped bundles). The lateral surface of the medulla oblongata, located between the sulci posterolateralis and anterolateralis, corresponds to the lateral funiculus. The XI, X and IX pairs of cranial nerves emerge from the sulcus posterolateralis behind the olive. The medulla oblongata includes the lower part of the rhomboid fossa.
Internal structure of the medulla oblongata. The medulla oblongata arose in connection with the development of the organs of gravity and hearing, as well as in connection with the gill apparatus, which is related to respiration and blood circulation. Therefore, it contains the nuclei of gray matter, which are related to balance, coordination of movements, as well as to the regulation of metabolism, respiration and blood circulation.
1. Nucleus olivaris, the nucleus of the olive, has the appearance of a convoluted plate of gray matter, open medially (hilus), and causes protrusion of the olive from the outside. It is connected with the dentate nucleus of the cerebellum and is an intermediate nucleus of balance, most pronounced in humans, whose vertical position requires a perfect gravitational apparatus. (The nucleus olivaris accessorius medialis is also found.)
2. Fomatio reticularis, reticular formation formed from the interweaving of nerve fibers and nerve cells lying between them.
3. Nuclei of four pairs of lower cranial nerves (XII-IX), related to the innervation of derivatives of the branchial apparatus and viscera.
4. Vital centers of respiration and blood circulation associated with the nuclei of the vagus nerve. Therefore, if the medulla oblongata is damaged, death can occur.
The white matter of the medulla oblongata contains long and short fibers. The long ones include descending pyramidal tracts that pass transitively into the anterior cords of the spinal cord, partly crossing in the area of the pyramids. In addition, in the nuclei of the dorsal funiculi (nuclei gracilis et cuneatus) there are the bodies of the second neurons of the ascending sensory pathways. Their processes go from the medulla oblongata to the thalamus, tractus bulbothalamicus. The fibers of this bundle form the medial loop, lemniscus medialis,
which in the medulla oblongata crosses, decussatio lemniscorum, and in the form of a bundle of fibers located dorsal to the pyramids, between the olives - the interliving loop layer - id et further. Thus, in the medulla oblongata there are two intersections of long pathways: the ventral motor pathway, decussatio ramidum, and the dorsal sensory pathway, decussatio lemniscorum.
Short pathways include bundles of nerve fibers that connect individual nuclei of the gray matter, as well as the nuclei of the medulla oblongata with neighboring parts of the brain . Among them it is worth noting the tractus olivocerebellaris and the fasciculum longitudinalis medialis lying dorsal to the interliving layer. Topographical relationships of the main formations of the medulla oblongata
visible on a cross section taken at the level of the olives. The roots extending from the nuclei of the hypoglossal and vagus nerves divide the medulla oblongata on both sides into three regions: posterior, lateral and anterior. In the back lie the nuclei of the posterior cord and the lower cerebellar peduncles, in the lateral are the olive nucleus and formatio reticularis, and in the anterior are the pyramids.
4. Branchiogenic endocrine glands: thyroid, parathyroid. Their structure, blood supply, innervation.
The thyroid gland, glandula thyroidea, the largest of the endocrine glands in an adult, is located in the neck in front of the trachea and on the lateral walls of the larynx, partially adjacent to the thyroid cartilage, which is where it gets its name. It consists of two lateral lobes, lobi dexter et sinister, and an isthmus, isthmus, lying transversely and connecting the lateral lobes to each other near their lower ends. A thin process extends upward from the isthmus, called lobus pyramidalis, which can extend up to
hyoid bone. With their upper part, the lateral lobes extend onto the outer surface of the thyroid cartilage, covering the lower horn and the adjacent section of the cartilage; downwards they reach the fifth - sixth ring of the trachea; The isthmus with its posterior surface is adjacent to the second and third rings of the trachea, sometimes reaching with its upper edge the cricoid cartilage. The posterior surface of the lobes is in contact with the walls of the pharynx and esophagus. The outer surface of the thyroid gland is convex, the inner surface, facing the trachea and larynx, is concave. In front, the thyroid gland is covered with skin, subcutaneous tissue, fascia of the neck, giving the gland
external capsule, capsula fibrosa, and muscles: mm. sternohyoideus, sternothyroideus et omohyoideus. The capsule sends processes into the gland tissue, which divide it into lobules consisting of follicles, folliculi gl. thyroideae, containing a colloid (it contains the iodine-containing substance thyroidin).
The diameter of the gland is about 50 - 60 mm, in the anteroposterior direction in the area of the lateral lobes it is 18 - 20 mm, and at the level of the isthmus it is 6 - 8 mm. The mass is about 30 - 40 g; in women the mass of the gland is slightly larger than in men, and sometimes increases periodically (during menstruation).
In the fetus and in early childhood, the thyroid gland is relatively larger than in an adult.
Function. The importance of the gland for the body is great. Its congenital underdevelopment causes myxedema and cretinism. The proper development of tissues, in particular the skeletal system, metabolism, functioning of the nervous system, etc., depends on the brake of the gland. In some areas, dysfunction of the thyroid gland causes the so-called endemic goiter. The hormone thyroxine produced by the gland accelerates oxidation processes in the body, and thyrocalcitonin regulates calcium levels. With hypersecretion of the thyroid gland, a symptom complex called Graves' disease is observed.
The parathyroid glands, glandulae parathyroideae (epithelial bodies), usually numbering 4 (two upper and two lower), are small bodies located on the posterior surface of the lateral lobes of the thyroid gland. Their dimensions are on average 6 mm long, 4 mm wide, and thickness 2 mm. To the naked eye, they can sometimes be mixed with fat lobules, accessory thyroid glands, or detached parts of the thymus gland.
Function. Regulates the exchange of calcium and phosphorus in the body (parathyroid hormone). Extirpation of the glands leads to death in cases of tetany.
Development and variations. The parathyroid glands develop from the third and fourth gill pouches. Thus, like the thyroid, in their development they are connected with the digestive canal. Their number can vary: rarely less than 4, relatively more often the number is increased (5-12). Sometimes they are almost completely immersed in the thickness of the thyroid gland.
Vessels and nerves. Blood supply from branches a. thyroidea inferior, a. thyroidea superior, and in some cases from the branches of the arteries of the esophagus and trachea. Wide sinusoidal capillaries are inserted between the arteries and veins. The sources of innervation are the same as the innervation of the thyroid gland; the number of nerve branches is large.
Ticket No. 17 (medical faculty)
1. Development of the skull in ontogenesis. Individual, age and gender characteristics of the skull.
The skull is one of the most complex in structure and important parts of the human skeleton. When studying the structure of the skull in an adult, one should proceed from the relationship between the shape and structure of the skull and its function, as well as from the history of the development of the skull during the evolution of vertebrates and in the individual development of humans.
Its development occurs so quickly and, most importantly, moves so much to earlier stages of embryonic development that the cartilaginous skull begins to interfere with this. In this regard, cartilage is formed only in the area of the base of the skull, and the lateral walls and vault of the cranial skull, i.e., those parts that are in the direction of preferential growth of the end brain, appear first as connective tissue membranous, and then, bypassing the cartilaginous stage of development, immediately ossify. And in humans, at the beginning of the 3rd month of intrauterine life, when the fetal body length is about 30 mm, only the base of the skull and the capsules of the olfactory, visual and auditory organs are represented by cartilage. The lateral walls and vault of the brain skull, as well as most of the facial skull, bypassing the cartilaginous stage of development, begin to ossify already at the end of the 2nd month of intrauterine life.
The apex of the right lung in front protrudes above the clavicle by 2 cm, and above the 1st rib - by 3-4 cm. In the back, the apex of the lung is projected at the level of the spinous process of the 7th cervical spine.
Anterior border of the right lung is carried out from its apex obliquely downwards and inwards through the sternoclavicular joint to the junction of the manubrium and the body of the sternum. From here, the anterior border of the right lung descends along the body of the sternum almost vertically to the level of the cartilage of the VI rib, where it passes into the lower border. Anterior border of the left lung from its apex it reaches along the sternum only to the level of the cartilage of the IV rib, then deviates to the left by 4-5 cm, crosses obliquely the cartilage of the V rib, reaches the VI rib, where it continues to the lower border. This difference in the anterior border of the right and left lungs is due to the asymmetrical location of the heart: most of it is located to the left of the median plane.
Lower limit The lungs correspond along the mid-clavicular line to the VI rib, along the mid-axillary line to the VIII rib, along the scapular line to the X rib, and along the paravertebral line to the XI rib. In the projection of the lower border of the right and left lungs, there is a difference of 1 - 2 cm (on the left it is lower). Posterior border lungs passes along the paravertebral line.
With maximum inhalation, the lower edge, especially along the last lines, drops by 5-7 cm.
Pleura- serous membrane lining the inner surface of the chest wall and the outer surface of the lungs, forming two isolated sacs. The pleura lining the walls of the chest cavity is called parietal, or parietal. It distinguishes between the costal pleura (covering the ribs and intercostal spaces, the diaphragmatic pleura, lining the upper surface of the diaphragm, and the mediastinal pleura, limiting the mediastinum. Pulmonary, or visceral, the pleura covers the outer and interlobar surfaces of the lungs. It is tightly fused with the lung parenchyma, and its deep layers form partitions that separate the pulmonary lobules. Between the visceral and parietal layers of the pleura there is a closed isolated space - a slit-like pleural cavity. Normally it contains a small amount of liquid up to 20 ml - it facilitates the respiratory movements of the lungs. The sealed pleural cavity is moistened and there is no air in it, and the pressure in it is negative. Thanks to this, the lungs are always pressed tightly against the wall of the chest cavity, and their volume always changes along with the volume of the chest cavity.
At the points of transition of parts of the parietal pleura into each other in the pleural cavity, depressions are formed - pleural sinuses1) costo-diaphragmatic sinus, recessus costodiaphragmaticus, is located at the place of transition of the costal pleura into the diaphragmatic one; 2) costo-mediastinal sinuses, recessus costomediastinales, are formed at the places of transition of the costal pleura pleura to mediastinal; the anterior sinus is behind the sternum, the posterior sinus, less pronounced, is in front of the spinal column;
3) the diaphragmomediastinal sinus, recessus phrenicomediastinalis, lies at the junction of the mediastinal pleura into the phrenic pleura. The sinuses do not fill with the lungs even with a deep breath; fluid accumulates in them first when hydrothorax develops.
The border of the visceral layer of the pleura coincides with the border of the lungs, and the parietal layer is different. Pariet. the pleura adheres to the head of the 1st rib and a pleural dome is formed 3-4 cm higher. In the back, it descends to the head of the 12th rib. In the front, along the right half, it descends to the 6th rib along the inner surface of the sternum. In the left half, the 6th ribs parallel the right leaf to the cartilage, then to the left by 3-5 cm and at the level of 6 ribs it turns into the diaphragm.
2. Intercostal branches, their topography and areas of innervation. Sacral plexus, its topography. Short and long branches. Areas of innervation
The posterior intercostal arteries arise from the aorta, and the anterior intercostal arteries arise from the internal mammary artery. Thanks to numerous anastomoses, they form a single arterial ring, the rupture of which can lead to severe bleeding from both ends of the damaged vessel. Difficulties in stopping bleeding from the intercostal arteries are also explained by the fact that the intercostal vessels are closely connected to the periosteum of the ribs and the fascial sheaths of the intercostal muscles, which is why their walls do not collapse when injured.
Intercostal nerves, nn. intercostales, pass in the intercostal spaces between the external and internal intercostal muscles. Each intercostal nerve, as well as the subcostal nerve, initially lies under the lower edge of the corresponding rib, in a groove along with the artery and vein. The upper six intercostal nerves reach the sternum and are called the anterior cutaneous branches, rr. cutanei anteriares, end in the skin of the anterior chest wall. The five lower intercostal nerves and the subcostal nerve continue into the anterior wall of the abdomen, penetrate between the internal oblique and transverse abdominal muscles, pierce the wall of the rectus abdominis sheath, innervate these muscles with muscular branches and end in the skin of the anterior abdominal wall.
The following muscles are innervated: external and internal intercostal muscles, subcostal muscles, levator ribs, transverse thoracis, transverse abdominis, internal and external obliques, rectus abdominis, quadratus lumborum and pyramidalis muscles. Each intercostal nerve gives off a lateral cutaneous branch, cutaneus lateralis, and an anterior cutaneous branch, cutaneus anterior), innervating the skin of the chest and abdomen. The lateral cutaneous branches arise at the level of the midaxillary line and are in turn divided into anterior and posterior branches. The lateral cutaneous branches of the II and III intercostal nerves connect to the medial cutaneous nerve of the shoulder and are called intercostobrachial nerves, nn. Intercostobrachiales. The anterior cutaneous branches arise from the intercostal nerves at the edge of the sternum and the rectus abdominis muscle.
The sacral plexus (plexus sacralis) is paired, formed by the abdominal branches of the IV and V lumbar nerves, I, II and III sacral spinal nerves. The branches of the IV and V lumbar nerves form one bundle, called the lumbosacral trunk (truncus lumbosacralis), which is included in the sacral plexus. Fibers from the lower lumbar and sacral nodes of the sympathetic trunk also enter this plexus. The branches of the sacral plexus are located in the small pelvis on the piriformis muscle.
Short mixed branches of the sacral plexus. 1. Muscular branches (rr. musculares), formed by fibers LIV-V and SI-II, innervate mm. piriformis, obturatorius internus and innervate the quadriceps femoris muscle (m. quadratus femoris). These muscles have receptors.
2. The superior gluteal nerve (n. gluteus superior) is formed by fibers LII-V and SI, represented by a short trunk, exits the small pelvis through the supragiriform foramen to the posterior surface of the pelvis, uniting into a common bundle with the arteries and vein of the same name. The nerve is divided into three branches that innervate the gluteus minimus, gluteus medius and m. tensor fasciae latae.
Fiber receptors are located in the small and medium muscles and fascia.
3. The lower gluteal nerve (n. gluteus inferior) is formed by LV and SI-II fibers, represented by a short trunk that extends to the posterior surface of the pelvis through the infrapiriform opening along with blood vessels. Innervates the gluteus maximus muscle. Receptors are located in the gluteus maximus muscle and the capsule of the hip joint. The sensory nerve fibers connect with motor fibers and travel to the nuclei of the spinal cord.
Long branches of the sacral plexus. 1. The posterior cutaneous nerve of the thigh (n. cutaneus femoris posterior) is long and thin, sensitive. Its receptors are located in the skin, tissue and fascia of the posterior thigh, popliteal fossa, in the skin of the perineum and the lower part of the gluteal region. Thin branches and the main trunk are located in the subcutaneous tissue of the thigh fascia. Then along the midline of the gluteal fold at the lower edge of m. The gluteus maximus nerve passes through the fascial layer and accompanies the sciatic nerve. Through the inferior pyriform opening it penetrates into the pelvic cavity and enters into the formation of the posterior roots LI-III.
1. Anatomical characteristics of the dentofacial segments of the upper and lower jaw.The dentofacial segment combines the jaw area and the tooth with the periodontium. The segments of the 1st and 2nd incisors and canines are distinguished; 1st and 2nd premolars; 1st, 2nd and 3rd molars. The boundary between the segments is a plane drawn through the middle of the interalveolar septum. The basis of each segment is the alveolar process (for the upper jaw) or the alveolar part (for the lower jaw).
Dentofacial segments of the upper jaw. Incisor-maxillary segments. With a narrow and high upper jaw, the incisal segments are elongated in height. The 2nd incisal segment includes part of the frontal process. The thickness of the outer compact plate of the alveolar process at the neck of the tooth is 1 mm, at the level of the root - 1 mm, the inner plate - 1-1.5 mm. The spongy substance consists of long bone beams that are directed into the palatine process, and in the 2nd incisal segment also into the frontal. Oval-shaped cells up to 2.5 mm in size are oriented along the beams. On preparations with a short and wide jaw shape, the incisal segments resemble an equilateral triangle and consist of the alveolar and palatine processes.
Canine-maxillary segments. The shape of the canine segments with a narrow and high upper jaw resembles a truncated cone with the base facing upward, and with a wide and short jaw it approaches rectangular. The extradental part of the segment is formed by the body, frontal and alveolar processes. The nature of the structure of the spongy substance is similar to that in the incisive segments. However, part of the bone beams in both forms of the segment is directed to the frontal process. The thickness of the outer compact plate with a narrow form above the root is at least 1.5 mm, at the level of the root - at least 1 mm. With a wide jaw, the maxillary sinus can be determined at the level of this segment.
Premolar-maxillary segments. The shape of the alveolar process is close to a rectangle, more elongated in preparations of a high and narrow upper jaw. On specimens with a short and wide upper jaw, this segment may contain the corresponding part of the maxillary sinus. The thickness of the outer and inner plates of the compact substance of the alveolar process is about 1 mm. The beams of spongy substance in this form are directed from the top of the buccal root socket (at the level of the 4th tooth) to the area of the anterior, medial wall of the maxillary sinus and to its bottom. From the hole of the palatine root, the beams rush to the base and into the thickness of the palatine process.
Molar-maxillary segments. The 1st, 2nd and 3rd molar-maxillary segments usually include the lower wall of the maxillary sinus. The alveolar process of these segments and the maxillary sinus with a high and narrow jaw are elongated in height, the walls of the sinus are located almost vertically. The bone beams are long, directed into the palatine and zygomatic processes. The thickness of the compact plates of the alveolar process and the body are short and wide. The bone plates are short, evenly distributed and directed not only to the processes, but also to the bottom of the medial wall of the maxillary sinus. The thickness of the compact substance of the alveolar process is no more than 1.5 mm.
Dentofacial segments of the lower jaw.
Incisor-maxillary segments. With a narrow and long lower jaw, the incisal segments are elongated along the height of its body. The thickness of the outer compact plate at the middle of the segment height is at least 2 mm, the inner one - at least 2.5 mm. The bone beams are directed along the height of the segment from the walls of the socket, limiting oval-shaped cells measuring 1-2 mm. On specimens with a short and wide lower jaw, the segments are short, with a widened base. The thickness of the outer wall is no more than 1.5 mm, the inner wall is no more than 2 mm. The spongy substance is characterized by thin short bone beams that limit round-shaped cells measuring 1-1.5 mm.
Canine-maxillary segments. The shape of the canine-maxillary segments with a long and narrow lower jaw is close to rectangular. The thickness of the outer wall of the segment hole is 1.5 mm, the inner wall is 3 mm. With a wide and short lower jaw, the segments are shorter and have thinner walls. In the spongy substance, a group of beams can be distinguished, which, starting from the lower wall of the segment, goes to the top of the socket. Premolar-maxillary segments. On preparations with a narrow and long jaw, the shape of the segments is rectangular. The thickness of the outer and inner walls of the holes is 2 mm. In short and wide jaws, the shape of the segments is close to oval, the thickness of the compact substance along all the walls of the segment socket is somewhat less than on a narrow and long jaw.
Molar-maxillary segments. On preparations with a narrow and long jaw, the 2nd and 3rd molar-maxillary segments have an irregular round shape, the 3rd molar-maxillary segment has the shape of a triangle. The thickness of the compact substance of the outer wall of the hole is at least 3.5 mm, the inner one is 1.5-2 mm. The spongy substance of the molar-maxillary segments is characterized by a coarse cellular structure
2. Blood supply to the brain and spinal cord. Arterial circle of the cerebrum.
1) Blood supply to the brain carried out by the branches of the left and right internal carotid arteries and the branches of the vertebral arteries.
The internal carotid artery on the left arises directly from the aorta, on the right - from the subclavian artery. It penetrates into the cranial cavity through a special canal and enters there on both sides of the sella turcica and the optic chiasm. Here a branch immediately departs from it - the anterior cerebral artery. Both anterior cerebral arteries are connected to each other by the anterior communicating artery. The direct continuation of the internal carotid artery is the middle cerebral artery.
The vertebral artery arises from the subclavian artery, passes through the canal of the transverse processes of the cervical vertebrae, enters the skull through the foramen magnum and is located at the base of the medulla oblongata. At the border of the medulla oblongata and the pons, both vertebral arteries are connected into one common trunk - the basilar artery. The basilar artery divides into two posterior cerebral arteries. Each posterior cerebral artery is connected to the middle cerebral artery by means of the posterior communicating artery. Thus, at the base of the brain, a closed arterial circle is obtained, called the Wellisian arterial circle (Fig. 33): the basilar artery, the posterior cerebral arteries (anastomosing with the middle cerebral artery), the anterior cerebral arteries (anastomosing with each other). From each vertebral artery, two branches depart and go down to the spinal cord, which merge into one anterior spinal artery. Thus, on the basis of the medulla oblongata, a second arterial circle is formed - the Zakharchenko circle.
Anterior cerebral artery supplies the cortex and subcortical white matter of the inner surface of the frontal and parietal lobes, the lower surface of the frontal lobe lying on the orbit, the narrow rim of the anterior and upper parts of the outer surface of the frontal and parietal lobes (the upper parts of the anterior and posterior central gyri), the olfactory tract, the anterior 4/5 corpus callosum, part of the caudate and lentiform nuclei, anterior femur of the internal capsule.
Middle cerebral artery supplies the cortex and subcortical white matter of most of the outer surface of the frontal and parietal lobes, the middle part of the occipital lobe and most of the temporal lobe.
The middle cerebral artery also supplies blood to the knee and the anterior 2/3 of the internal capsule, part of the caudate, lenticular nuclei and the optic thalamus.
Posterior cerebral artery supplies blood to the cortex and subcortical white matter of the occipital lobe (with the exception of its middle part on the convex surface of the hemisphere), the posterior part of the parietal lobe, the lower and posterior parts of the temporal lobe, the posterior parts of the visual thalamus, the hypothalamus, the corpus callosum, the caudate nucleus, as well as the quadrigemone and cerebral peduncles
Smaller branches of blood vessels in the pia mater reach the brain, penetrate its substance, where they are divided into numerous capillaries. From the capillaries, blood collects into small and then large venous vessels. Blood from the brain flows into the sinuses of the dura mater. From the sinuses, blood flows through the jugular openings at the base of the skull into the internal jugular veins.
2)
The blood supply to the spinal cord is carried out by the anterior and two posterior spinal arteries, which anastomose with each other and create segmental arterial rings. The spinal arteries receive blood from the vertebral arteries. The outflow of venous blood goes through the veins of the same name into the internal spinal plexus, located along the entire length of the spinal canal outside the dura mater of the spinal cord. From the internal spinal plexus, blood flows into the veins running along the spinal column, and from them into the inferior and superior vena cava.
Ticket 55.
1. Unstriated (smooth) and striated skeletal (striated) muscle tissue, structural features and functions. Muscle development.
Smooth (non-striated) muscle tissue is located in the walls of hollow internal organs, blood and lymph vessels, gland ducts, as well as in some other organs. This tissue consists of spindle-shaped smooth muscle cells (myocytes). The length of the smooth muscle cell is about 100 microns. Smooth muscle tissue contracts involuntarily, obeying the impulses of the autonomic (autonomic) nervous system, which is not under the control of our consciousness.
Striated (striated) muscle tissue forms skeletal muscle, which is why it is also called skeletal muscle tissue. This fabric is constructed from fibers ranging in length from fractions of a millimeter to several centimeters. Each muscle fiber has up to 100 or more nuclei. The fibers have alternating light and dark colors, which is why the fabric got its name. Striated muscle tissue contracts voluntarily, subject to conscious movements and willpower.
The visceral pleura is a thin serous membrane surrounding each lung.. It consists of squamous epithelium attached to the basement membrane, which provides nutrition to the cells. Epithelial cells have many microvilli on their surface. The connective tissue base contains elastin and collagen fibers. Smooth muscle cells are also found in the visceral pleura.
Where is the pleura located?
The visceral pleura is located on the entire surface of the lungs, extending into the cracks between their lobes. It adheres so tightly to the organ that it cannot be separated from the lung tissues without compromising their integrity. The visceral pleura becomes parietal in the region of the roots of the lung. Its leaves form a fold that descends all the way to the diaphragm - the pulmonary ligament.
The parietal pleura forms closed pockets where the lungs are located. It is divided into three parts:
- costal;
- mediastinal;
- diaphragmatic.
The rib region covers the areas between the ribs and the inner surface of the ribs. The mediastinal pleura separates the pleural cavity from the mediastinum, and in the region of the root of the lung it passes into the visceral membrane. The diaphragmatic part closes the diaphragm on top.
The dome of the pleura is located several centimeters above the collarbones. The anterior and posterior borders of the membranes coincide with the edges of the lungs. The lower border is one rib below the corresponding border of the organ.
Innervation and blood supply of the pleura
The sheath is innervated by fibers of the vagus nerve. The nerve endings of the autonomic nerve plexus of the mediastinum extend to the parietal leaf, and the vegetative pulmonary plexus to the visceral leaf. The highest density of nerve endings is observed in the area of the pulmonary ligament and at the junction of the heart. The parietal pleura contains encapsulated and free receptors, while the visceral pleura contains only non-encapsulated ones.
Blood supply is provided by the intercostal and internal mammary arteries. Trophism of the visceral areas is also provided by branches of the phrenic artery.
What is the pleural cavity
The pleural cavity is the gap between the parietal and pulmonary pleura. It is also called a potential cavity because it is so narrow that it is not a physical cavity. It contains a small amount of interstitial fluid, which facilitates respiratory movements. The liquid also contains tissue proteins, which give it mucoid properties.
When an excessive amount of fluid accumulates in the cavity, the excess is absorbed through the lymphatic vessels into the mediastinum and the upper cavity of the diaphragm. The constant outflow of fluid provides negative pressure in the pleural fissure. Normally, the pressure is at least 4 mm Hg. Art. Its value varies depending on the phase of the respiratory cycle.
Age-related changes in the pleura
In newborn children, the pleura is loose, the number of elastic fibers and smooth muscle cells in it is reduced compared to adults. Because of this, children are more likely to suffer from pneumonia and their disease is more severe. The organs of the mediastinum in early childhood are surrounded by loose connective tissue, which causes greater mobility of the mediastinum. With pneumonia and pleurisy, the child’s mediastinal organs are compressed and their blood supply is disrupted.
The upper boundaries of the pleura do not extend beyond the clavicles, the lower boundaries are located one rib higher than in adults. The upper space between the domes of the membrane is occupied by a large thymus. In some cases, the visceral and parietal layers in the area behind the sternum are closed and form the mesentery of the heart.
At the end of the first year of life, the structure of the child’s pleura already corresponds to the structure of the membranes of the lungs of an adult. The final development and differentiation of the membrane is completed at the age of 7 years. Its growth occurs parallel to the general growth of the whole body. The anatomy of the pleura fully corresponds to its functions.
In a newborn baby, during exhalation, the pressure in the pleural fissure is equal to atmospheric pressure, due to the fact that the volume of the chest is equal to the volume of the lungs. Negative pressure appears only during inspiration and is about 7 mmHg. Art. This phenomenon is explained by the low extensibility of the respiratory tissues of children.
During the aging process, connective tissue adhesions appear in the pleural cavity. The lower border of the pleura in older people shifts downward.
Participation of the pleura in the breathing process
The following functions of the pleura are distinguished:
- protects lung tissue;
- participates in the act of breathing;
The size of the chest during development increases faster than the size of the lungs. The lungs are always in an expanded state, as they are exposed to atmospheric air. Their extensibility is limited only by the volume of the chest. The respiratory organ is also affected by a force that tends to cause collapse of the lung tissue - elastic traction of the lungs. Its appearance is due to the presence of smooth muscle elements, collagen and elastin fibers in the bronchi and alveoli, and the properties of surfactant - a liquid covering the inner surface of the alveoli.
The elastic traction of the lungs is much less than atmospheric pressure, and therefore cannot prevent the stretching of the lung tissues during breathing. But if the tightness of the pleural fissure is broken - pneumothorax - the lungs collapse. A similar pathology often occurs when cavities rupture in patients with tuberculosis or injuries.
Negative pressure in the pleural cavity is not the cause of keeping the lungs in a distended state, but a consequence. This is evidenced by the fact that in newborn children the pressure in the pleural fissure corresponds to atmospheric pressure, since the size of the chest is equal to the size of the respiratory organ. Negative pressure occurs only during inhalation and is associated with the low compliance of children's lungs. During development, the growth of the chest outpaces the growth of the lungs and they are gradually stretched by atmospheric air. Negative pressure appears not only when inhaling, but also when exhaling.
The adhesion force between the visceral and parietal layers contributes to the act of inhalation. But compared to the atmospheric pressure acting on the bronchi and alveoli through the airways, this force is extremely insignificant.
Pleural pathologies
Between the lungs and the boundaries of its parietal membrane there are small gaps - the sinuses of the pleura. The lung enters them during a deep breath. During inflammatory processes of various etiologies, exudate can accumulate in the pleural sinuses.
The same circumstances that provoke edema in other tissues can cause an increase in the amount of fluid in the pleural cavity:
- impaired lymphatic drainage;
- heart failure, in which the pressure in the vessels of the lungs increases and excessive transudation of fluid into the pleural cavity occurs;
- a decrease in colloid osmotic pressure of blood plasma, leading to accumulation of fluid in tissues.
In case of disruption and injury, blood, pus, gases, and lymph may accumulate in the pleural fissure. Inflammatory processes and injuries can cause fibrotic changes in the membranes of the lungs. Fibrothorax leads to limitation of respiratory movements, disruption of ventilation and blood circulation of the respiratory system. Due to decreased pulmonary ventilation, the body suffers from hypoxia.
Massive proliferation of connective tissue causes shrinkage of the lung. In this case, the chest is deformed, a cor pulmonale is formed, and the person suffers from severe respiratory failure.
Table of contents of the topic "Topography of the diaphragm. Topography of the pleura. Topography of the lungs.":The upper part of each pleural sac is called domes of pleura, cupula pleurae. Dome of pleura together with the apex of the corresponding lung entering it, it exits through the upper aperture in the neck area 3-4 cm above the anterior end of the first rib or 2-3 cm above the collarbone.
Rear projection domes of pleura corresponds to the level of the spinous process of the VII cervical vertebra, and the dome itself is adjacent to the head and neck of the 1st rib, the long muscles of the neck, and the lower cervical ganglion of the sympathetic trunk.
From the lateral side dome of pleura limit mm. scaleni anterior et medius, from the space between which emerge the trunks of the brachial plexus. Directly on dome of pleura the subclavian arteries are located.
Dome of pleura connected by fiber to the membrana suprapleuralis (part of the intrathoracic fascia), separating the pleural cavity from the organs of the neck.
Depending on the parts of the chest cavity to which the parietal pleura, it distinguishes between the costal, diaphragmatic and mediastinal (mediastinal) parts (pars costalis, diaphragmatica and mediastinalis).
Pars costalis pleura the most extensive part of the parietal pleura, closely connected with the intrathoracic fascia covering the inside of the ribs and intercostal spaces.
Pars diaphragmatica of the pleura covers the upper surface of the diaphragm, with the exception of the middle part, where the pericardium is directly adjacent to the diaphragm.
Pars mediastinalis pleura It is located in the anteroposterior direction (sagittal): it runs from the posterior surface of the sternum to the lateral surface of the spine and is adjacent medially to the organs of the mediastinum.
Posteriorly on the spine and anteriorly on the sternum mediastinal part of the pleura passes directly into the costal part, below at the base of the pericardium - into the diaphragmatic pleura, and at the root of the lung - into the visceral pleura. When one part of the parietal pleura passes into another, transitional folds of pleura, which define the boundaries of the parietal pleura and, therefore, pleural cavity.
Anterior borders of the pleura, corresponding to the line of transition of the costal part of the pleura to the mediastinal one, are located asymmetrically on the right and left sides, since the heart pushes aside the left pleural fold.
Right anterior border of the pleura from domes of pleura descends to the sternoclavicular joint and goes down behind the manubrium of the sternum to the middle of its connection with the body of the sternum (at the level of the cartilage of the 2nd rib). Then it descends down to the left of the midline to the level of attachment of the cartilage of the VI rib to the sternum, from where it passes into the lower border of the pleural cavity.
Left anterior border of the pleura also passes behind the sternoclavicular joint, then obliquely and down to the midline. At the level of the IV rib, it deviates laterally, leaving the triangular area of the pericardium located here not covered by the pleura.
Then the front border of the parietal pleura descends parallel to the edge of the sternum to the cartilage of the VI rib, where it deviates laterally downwards, passing into the lower border.
