Features of the structure of the walls of blood vessels. Blood vessel
AFO Cardio vascular system.
Anatomy and physiology of the heart.
The structure of the circulatory system. Features of the structure in different age periods. The essence of the process of blood circulation. Structures that carry out the process of blood circulation. The main indicators of blood circulation (number of heartbeats, arterial pressure, electrocardiogram parameters). Factors affecting blood circulation (physical and nutritional stress, stress, lifestyle, bad habits etc.). Circles of blood circulation. Vessels, types. The structure of the walls of blood vessels. Heart is location external structure, anatomical axis, surface projection chest at different age periods. Chambers of the heart, orifices and valves of the heart. Principles of operation of heart valves. The structure of the heart wall - endocardium, myocardium, epicardium, location, physiological properties. conduction system of the heart. Physiological properties. The structure of the pericardium. Vessels and nerves of the heart. Phases and duration of the cardiac cycle. Physiological properties of the heart muscle.
Circulatory system
The functions of the blood are carried out due to the continuous work of the circulatory system. Circulation - This is the movement of blood through the vessels, which ensures the exchange of substances between all tissues of the body and the external environment. The circulatory system includes the heart and blood vessels. Blood circulation in the human body through a closed cardiovascular system is provided by rhythmic contractions. hearts its central organ. Vessels that carry blood from the heart to tissues and organs are called arteries, and those through which blood is delivered to the heart, - veins. In tissues and organs, thin arteries (arterioles) and veins (venules) are interconnected by a dense network. blood capillaries.
Features of the structure in different age periods.
The heart of a newborn is rounded. Its transverse diameter is 2.7-3.9 cm, the average length of the heart is 3.0-3.5 cm. The anterior-posterior size is 1.7-2.6 cm. The atria are large compared to the ventricles, and the right of which is much larger than the left. The heart grows especially rapidly during the year of a child's life, and its length increases more than its width. Separate parts of the heart change in different age periods differently: during the 1st year of life, the atria grow stronger than the ventricles. At the age of 2 to 6 years, the growth of the atria and ventricles occurs equally intensively. After 10 years, the ventricles increase faster than the atria. total weight of the heart in a newborn is 24 g, at the end of the 1st year of life it increases by about 2 times, by 4-5 years - by 3 times, by 9-10 years - by 5 times and by 15-16 years - by 10 times. The mass of the heart up to 5-6 years is greater in boys than in girls, at 9-13 years, on the contrary, it is greater in girls, and at 15 years, the heart mass is again greater in boys than in girls. In newborns and infants, the heart is located high and lies transversely. The transition of the heart from a transverse to an oblique position begins at the end of the 1st year of a child's life.
Factors affecting blood circulation (physical and nutritional stress, stress, lifestyle, bad habits, etc.).
Circles of blood circulation.
Large and small circles of blood circulation. AT In the human body, blood moves through two circles of blood circulation - large (trunk) and small (pulmonary).
Systemic circulation begins in the left ventricle, from which arterial blood is ejected into the largest artery in diameter - aorta. The aorta curves to the left and then runs along the spine, branching into smaller arteries that carry blood to the organs. In the organs, the arteries branch into smaller vessels - arterioles, that go online capillaries, penetrating tissues and delivering oxygen to them and nutrients. Venous blood through the veins is collected in two large vessels - top and inferior vena cava, which infuse it into the right atrium.
Small circle of blood circulation begins in the right ventricle, from where the arterial pulmonary trunk exits, which is divided into pulmonary arteries, carrying blood to the lungs. In the lungs, large arteries branch into smaller arterioles, passing into a network of capillaries densely braiding the walls of the alveoli, where the exchange of gases takes place. Oxygenated arterial blood flows through the pulmonary veins into the left atrium. Thus, venous blood flows in the arteries of the pulmonary circulation, and arterial blood flows in the veins.
Not all of the blood in the body circulates evenly. Much of the blood is in blood depots- liver, spleen, lungs, subcutaneous vascular plexuses. The importance of blood depots lies in the ability to quickly provide oxygen to tissues and organs in emergency situations.
Vessels, types. The structure of the walls of blood vessels.
The wall of the vessel consists of three layers:
1. The inner layer very thin, it is formed by one row of endothelial cells, which give the smoothness of the inner surface of the vessels.
2. The middle layer is the thickest, it has a lot of muscle, elastic and collagen fibers. This layer provides strength to the vessels.
3. The outer layer is connective tissue, it separates the vessels from the surrounding tissues.
arteries The blood vessels that lead from the heart to the organs and carry blood to them are called arteries. Blood flows from the heart through the arteries under high pressure, so the arteries have thick elastic walls.
According to the structure of the walls of the arteries are divided into two groups:
Elastic type arteries - the arteries closest to the heart (the aorta and its large branches) perform mainly the function of conducting blood.
Arteries of the muscular type - medium and small arteries in which the inertia of the heart impulse weakens and its own contraction of the vascular wall is required to further move the blood
In relation to the organ, there are arteries that go outside the organ, before entering it - extraorganic arteries - and their continuations, branching inside it - intraorganic or intraorganic arteries. Lateral branches of the same trunk or branches of different trunks can be connected to each other. Such a connection of vessels before they break up into capillaries is called anastomosis or anastomosis (they are the majority). Arteries that do not have anastomoses with neighboring trunks before they pass into capillaries are called terminal arteries (for example, in the spleen). The terminal, or terminal, arteries are more easily clogged with a blood plug (thrombus) and predispose to the formation of a heart attack (local necrosis of the organ).
The last branches of the arteries become thin and small and therefore stand out under the name arterioles. They directly pass into the capillaries, and due to the presence of contractile elements in them, they perform a regulatory function.
An arteriole differs from an artery in that its wall has only one layer of smooth muscle, thanks to which it performs a regulatory function. The arteriole continues directly into the precapillary, in which the muscle cells are scattered and do not form a continuous layer. The precapillary differs from the arteriole also in that it is not accompanied by a venule, as is observed in relation to the arteriole. Numerous capillaries arise from the precapillary.
capillaries- the smallest blood vessels located in all tissues between arteries and veins. The main function of capillaries is to ensure the exchange of gases and nutrients between blood and tissues. In this regard, the capillary wall is formed by only one layer of flat endothelial cells, permeable to substances and gases dissolved in the liquid. Through it, oxygen and nutrients easily penetrate from the blood to the tissues, and carbon dioxide and waste products in the opposite direction.
At any given moment, only part of the capillaries (open capillaries) is functioning, while the other remains in reserve (closed capillaries).
Vienna- blood vessels that carry venous blood from organs and tissues to the heart. The exception is the pulmonary veins, which carry arterial blood from the lungs to the left atrium. The collection of veins forms the venous system, which is part of the cardiovascular system. The network of capillaries in the organs passes into small post-capillaries, or venules. At a considerable distance, they still retain a structure similar to that of capillaries, but have a wider lumen. Venules merge into larger veins, connected by anastomoses, and form venous plexuses in or near organs. From the plexuses, veins are collected that carry blood from the organ. There are superficial and deep veins. Superficial veins located in the subcutaneous adipose tissue, starting from the superficial venous networks; their number, size and position vary greatly. deep veins, starting on the periphery from small deep veins, accompany the arteries; often one artery is accompanied by two veins (“companion veins”). As a result of the confluence of the superficial and deep veins, two large venous trunks are formed - the superior and inferior vena cava, which flow into the right atrium, where the common drain of the cardiac veins, the coronary sinus, also flows. The portal vein carries blood from the unpaired organs of the abdominal cavity.
Low pressure and low blood flow velocity cause weak development of elastic fibers and membranes in the venous wall. The need to overcome the gravity of blood in the veins of the lower limb led to the development of muscle elements in their wall, in contrast to the veins of the upper limbs and the upper half of the body. On the inner shell of the vein there are valves that open along the blood flow and promote the movement of blood in the veins towards the heart. A feature of the venous vessels is the presence of valves in them, which are necessary to ensure the unidirectional flow of blood. The walls of the veins are arranged according to the same plan as the walls of the arteries, however, the blood pressure in the veins is very low, so the walls of the veins are thin, they have less elastic and muscle tissue, due to which the empty veins collapse.
Heart- a hollow fibromuscular organ that, functioning as a pump, ensures the movement of blood in the circulatory system. The heart is located in the anterior mediastinum in the pericardium between the sheets of the mediastinal pleura. It has the shape of an irregular cone with a base at the top and an apex facing downwards, to the left and anteriorly. S.'s sizes are individually various. The length of S. of an adult varies from 10 to 15 cm (usually 12-13 cm), the width at the base is 8-11 cm (usually 9-10 cm) and the anteroposterior size is 6-8.5 cm (usually 6.5-7 cm ). S.'s weight averages 332 g in men (from 274 to 385 g), in women - 253 g (from 203 to 302 g).
In relation to the midline of the body of the heart, it is located asymmetrically - about 2/3 to the left of it and about 1/3 to the right. Depending on the direction of the projection of the longitudinal axis (from the middle of its base to the top) on the anterior chest wall, there are transverse, oblique and vertical position hearts. The vertical position is more common in people with a narrow and long chest, the transverse position is more common in people with a wide and short chest.
The heart consists of four chambers: two (right and left) atria and two (right and left) ventricles. The atria are at the base of the heart. The aorta and the pulmonary trunk emerge from the heart in front, the superior vena cava flows into it on the right side, the inferior vena cava in the posterior inferior, the left pulmonary veins behind and to the left, and the right pulmonary veins somewhat to the right.
The function of the heart is to rhythmically pump blood into the arteries, which comes to it through the veins. The heart contracts about 70-75 times per minute at rest (1 time per 0.8 s). More than half of this time it rests - relaxes. The continuous activity of the heart consists of cycles, each of which consists of contraction (systole) and relaxation (diastole).
There are three phases of cardiac activity:
atrial contraction - atrial systole - takes 0.1 s
ventricular contraction - ventricular systole - takes 0.3 s
general pause - diastole (simultaneous relaxation of the atria and ventricles) - takes 0.4 s
Thus, during the entire cycle, the atria work 0.1 s and rest 0.7 s, the ventricles work 0.3 s and rest 0.5 s. This explains the ability of the heart muscle to work without fatigue throughout life. The high efficiency of the heart muscle is due to the increased blood supply to the heart. Approximately 10% of the blood ejected from the left ventricle into the aorta enters the arteries departing from it, which feed the heart.
BLOOD VESSELS (vasa sanguifera s. sanguinea) - elastic tubes of various calibers that make up a closed system, through which blood flows in the body from the heart to the periphery and from the periphery to the heart. The cardiovascular system of animals and humans ensures the transport of substances in the body and thereby participates in metabolic processes. It contains the circulatory system central authority- the heart (see), which acts as a pump, and the lymphatic system (see).
Comparative anatomy
The vascular system arises in the body of multicellular animals due to the need for cell life support. Nutrients absorbed from the intestinal tube are carried by fluid throughout the body. Extravascular transport of fluids through interstitial fissures is replaced by intravascular circulation; at the person in vessels circulates apprx. 20% of the total body fluid. Many invertebrates (insects, mollusks) have an open vascular system (Fig. 1a). In annelids, a closed hemolymph circulation appears (Fig. 1, b), although they still do not have a heart, and blood is pushed through the vessels due to the pulsation of 5 pairs of "hearts" - pulsating tubes; contractions of the muscles of the body help these "hearts". In lower vertebrates (lancelet), the heart is also absent, the blood is still colorless, the differentiation of arteries and veins is well expressed. In fish, at the anterior end of the body, near the gill apparatus, an expansion of the main vein appears, where the veins of the body are collected - the venous sinus (Fig. 2), followed by the atrium, ventricle and arterial cone. From it, blood enters the ventral aorta with its arterial gill arches. At the border of the venous sinus and the arterial cone, a valve appears that regulates the passage of blood. The heart of fish passes only venous blood. In the capillaries of the gill filaments, gases are exchanged, and oxygen dissolved in water enters the blood, in order to follow further along the dorsal aorta into the circulation circle and spread in the tissues. As a result of the change of gill breathing to pulmonary breathing in terrestrial animals (amphibians), a small (pulmonary) circulation occurs, and with it a three-chambered heart appears, consisting of two atria and one ventricle. The appearance of an incomplete septum in it is characteristic of reptiles, and in crocodiles the heart is already four-chambered. Birds and mammals, like humans, also have a four-chambered heart.
The appearance of the heart is due to an increase in tissue mass, an increase in resistance to blood flow. The original vessels (protocapillaries) were indifferent, equally loaded, and uniform in structure. Then the vessels delivering blood to a segment of the body or to an organ acquired the structural features characteristic of arterioles and arteries, and the vessels at the outlet of blood from the organ became veins. Between the primitive arterial vessels and the outflow tracts of blood, a capillary network of the organ was formed, which assumed all the metabolic functions. Arteries and veins have become typical transport vessels, some more resistive (arteries), others primarily capacitive (veins).
The arterial system in the process of evolutionary development turned out to be associated with the main arterial trunk - the dorsal aorta. Its branches penetrated all segments of the body, stretched along the hind limbs, took over the blood supply to all organs of the abdominal cavity and pelvis. From the ventral aorta with its gill arches originated the carotid arteries (from the third pair of branchial arterial arches), the aortic arch and the right subclavian artery (from the fourth pair of branchial arterial arches), the pulmonary trunk with the ductus arteriosus and pulmonary arteries (from the sixth pair of arterial branchial arches). With the formation of the arterial system of primates and humans, a restructuring of the arterial links occurred. So, the tail artery disappeared, the remnant of a swarm in humans is the median sacral artery. Instead of several renal arteries, a paired renal artery was formed. The arteries of the extremities underwent complex transformations. For example, the axillary, brachial, median, which later became the ancestor of the radial and ulnar arteries, stood out from the interosseous artery of the limbs of reptiles in mammals. The sciatic artery is the main arterial highway hind limb amphibians and reptiles - gave way to the femoral artery.
In the history of the development of venous vessels, the existence of two portal systems in lower vertebrates - hepatic and renal - was noted. The portal system of the kidneys is well developed in fish, amphibians, reptiles, weakly in birds.
With reduction in reptiles primary kidney the portal renal system disappeared. The final kidney appeared with its glomeruli and outflow of blood into the inferior vena cava. The paired anterior cardinal veins, which receive blood from the head in fish, as well as the paired posterior cardinal veins, lost their significance with the transition of animals to terrestrial life. Amphibians also retain the collectors connecting them - the Cuvier ducts that flow into the heart, but over time, in higher vertebrates, only the coronary sinus of the heart remains from them. Of the paired symmetrical anterior cardinal veins, a person retains the internal jugular veins, which merge together with the subclavian veins into the superior vena cava, from the posterior cardinal - asymmetric unpaired and semi-unpaired veins.
The portal system of the liver arises in fish in connection with the subintestinal vein. Initially, the hepatic veins flowed into the venous sinus of the heart, where blood also came from the cardinal veins through the right and left Cuvier ducts. With the extension of the venous sinus of the heart in the caudal direction, the orifices of the hepatic veins moved caudally. The trunk of the inferior vena cava was formed.
Limf, the system developed as a derivative of venous system or independently from it in connection with a parallel current of intersticial liquids as a result of merge of mesenchymal spaces. It is also assumed that the predecessor of the blood and lymphatic channels in vertebrates was the hemolymphatic system of invertebrates, in which nutrients and oxygen were transferred to the cells.
Anatomy
Blood supply to all organs and tissues in the human body is carried out by vessels great circle circulation. It starts from the left ventricle of the heart with the largest arterial trunk - the aorta (see) and ends in the right atrium, into which the largest venous vessels bodies - superior and inferior vena cava (see). Along the aorta from the heart to V lumbar vertebra numerous branches depart from it - to the head (printing. Fig. 3) common carotid arteries (see. Carotid artery), to the upper limbs - subclavian arteries (see. Subclavian artery), to the lower limbs - iliac arteries. arterial blood is delivered through the thinnest branches to all organs, including the skin, muscles, skeleton. There, passing through the microcirculatory bed, the blood gives off oxygen and nutrients, captures carbon dioxide and toxins to be removed from the body. Through the postcapillary venules, the blood, which has become venous, enters the tributaries of the vena cava.
Under the name "pulmonary circulation" stands out a complex of vessels that pass blood through the lungs. Its beginning is the pulmonary trunk emerging from the right ventricle of the heart (see), according to Krom, venous blood follows into the right and left pulmonary arteries and further into the capillaries of the lungs (printing. Fig. 4). Here, the blood gives off carbon dioxide, and captures oxygen from the air and is sent through the pulmonary veins from the lungs to the left atrium.
From the blood capillaries of the digestive tract, blood is collected in the portal vein (see) and goes to the liver. There it spreads through the labyrinths of thin vessels - sinusoidal capillaries, from which tributaries of the hepatic veins are then formed, flowing into the inferior vena cava.
Larger To. from among the main ones follow between organs and are designated as arterial highways and venous collectors. Arteries lie, as a rule, under the cover of muscles. They are sent to the blood-supplied organs along the shortest path. In accordance with this, they are deployed on the flexion surfaces of the limbs. Correspondence of arterial highways to the main formations of the skeleton is observed. There is a differentiation of the visceral and parietal arteries, the latter in the trunk region retain a segmental character (eg, intercostal arteries).
The distribution of arterial branches in the organs, according to M. G. Prives, is subject to certain laws. In parenchymal organs, either there are gates through which an artery enters, sending branches in all directions, or arterial branches sequentially enter the organ in steps along its length and are connected inside the organ by longitudinal anastomoses (for example, a muscle), or, finally, they penetrate into the organ arterial branches from several sources along the radii (eg, thyroid gland). Arterial blood supply hollow organs occurs in three types - radial, circular and longitudinal.
All veins in the human body are localized either superficially, in the subcutaneous tissue, or in the depths of the anatomical regions along the arteries, usually accompanied by pairs of veins. Superficial veins, due to multiple anastomoses, form venous plexuses. Deep venous plexuses are also known, for example, pterygoid on the head, epidural in spinal canal around the pelvic organs. A special type of venous vessels are the sinuses of the hard shell of the brain.
Variations and anomalies of large blood vessels
K. s. vary widely in position and size. Distinguish the malformations To. pages leading to pathology, and also the deviations which are not reflected in health of the person. Among the first are coarctation of the aorta (see), cleft ductus arteriosus (see), discharge of one of the coronary arteries of the heart from the pulmonary trunk, phlebectasia of the internal jugular vein, arteriovenous aneurysms (see Aneurysm). Much more often in practically healthy people there are varieties of the normal location of K. with., cases of their unusual development, compensated by reserve vessels. So, with dextrocardia, the right-sided position of the aorta is noted. The doubling of the superior and inferior vena cava does not cause any patol, disorders. Very diverse options for the departure of branches from the aortic arch. Sometimes additional arteries (eg, hepatic) and veins come to light. Often there is either a high confluence of veins (eg, common iliac veins during the formation of the inferior vena cava), or, conversely, a low one. This is reflected in the total length of K. s.
It is expedient to divide all variations To. depending on their localization and topography, on their number, branching or merging. At disturbance of a current of a blood on natural highways (eg, at injury or a prelum) new ways of a blood-groove are formed, the atypical picture of distribution To is created. (acquired anomalies).
Research methods
Methods of anatomical research. Distinguish methods of a research To. on dead preparations (preparation, injection, impregnation, staining, electron microscopy) and methods of in vivo research in the experiment (X-ray, capillaroscopy, etc.). Filling K. with. anatomists began to use coloring solutions or solidifying masses as early as the 17th century. Anatomists J. Swammerdam, F. Ruysch and I. Lieberkün achieved great success in injection technique.
On anatomical preparations, arterial injection is achieved by inserting an injection needle into the vessel lumen and filling it with a syringe. It is more difficult to inject veins that have valves inside. In the 40s. 20th century A. T. Akilova, G. M. Shulyak proposed a method for injecting veins through the spongy bone, where an injection needle is inserted.
In the manufacture of vascular preparations, the injection method is often combined with the corrosion method, developed in the middle of the 19th century by J. Girtle. The mass introduced into the vessels (molten metals, hot hardening substances - wax, paraffin, etc.) gives casts choroid plexus, the composition of which remains after the melting of all surrounding tissues strong to - that (Fig. 3). Modern plastic materials create conditions for the production of corrosive preparations of jewelry fineness.
Of particular value is the injection To. solution of silver nitrate, which allows, when studying their walls, to see the boundaries of endothelial cells. Impregnation K. s. silver nitrate by immersing fragments of organs or membranes in special solution developed by V. V. Kupriyanov in the 60s. 20th century (tsvetn. fig. 2). She laid the foundation for non-injection methods for studying the vascular bed. These include luminescent microscopy of microvessels, histochemicals, their detection, and subsequently - electron microscopy (including transmission, scanning, scanning) of the vascular walls. In the experiment, intravital administration of radiopaque suspensions (angiography) into the vessels is widely carried out in order to diagnose developmental anomalies. helper method it is necessary to consider a X-ray analysis To. pages, into a gleam of which enter a catheter from radiopaque materials.
Due to the improvement of optics for capillaroscopy (see), it is possible to observe K. page. and capillaries in the conjunctiva of the eyeball. Reliable results are given by photographing To. page. retina through the pupil using a retinophoto apparatus.
Data of intravital research of anatomy To. in experimental animals, they are documented by photographs and films, on which accurate morphometric measurements are made.
Research methods in the clinic
Survey of the patient with various pathology To. page, as well as other patients, has to be complex. It begins with anamnesis, examination, palpation and auscultation and ends with instrumental research methods, bloodless and surgical.
Bloodless research To. should be carried out in an isolated spacious, well-lit (preferably daylight) room with constant temperature not lower than 20°. Surgical research methods must be carried out in a specially equipped X-ray operating room, equipped with everything necessary, including for combating possible complications with full asepsis.
When collecting an anamnesis, special attention is paid to occupational and household hazards (frostbite and frequent cooling of the extremities, smoking). Among the complaints, special attention should be paid to the chilliness of the lower extremities, fatigue when walking, paresthesia, dizziness, unsteadiness of gait, etc. Particular attention is paid to the presence and nature of pain, a feeling of heaviness, fullness, fatigue of the limb after standing or physical. stress, the appearance of edema, skin itching. Establish the dependence of complaints on the position of the body, season, find out their connection with common diseases, trauma, pregnancy, operations, etc. Be sure to specify the sequence and time of occurrence of each complaint.
The patient is undressed and examined in a supine and standing position, while comparing the symmetrical parts of the body and especially the limbs, noting their configuration, the color of the skin, the presence of areas of pigmentation and hyperemia, the nature of the pattern of the saphenous veins, the presence of expansion of the superficial veins and their nature, localization and prevalence . Exploring the lower limbs, fix attention on the vascular pattern of the anterior abdominal wall, gluteal regions and lower back. When examining the upper limbs, the condition of the vessels and skin of the neck, shoulder girdle and chest is taken into account. At the same time, attention is paid to the difference in the circumference and volume of individual segments of the limbs in a horizontal and vertical position, the presence of edema and pulsating formations along the vascular bundles, the severity of the hairline, the color and dryness of the skin, and in particular its individual sections.
The turgor of the skin, the severity of the skin fold, seals along the vessels, painful points, the localization and size of defects in the aponeurosis are determined, the temperature of the skin of different sections of the same limb and in symmetrical areas of both limbs is compared, the skin is felt in the zone of trophic lesions.
When examining the state of blood circulation in the extremities, palpation of the main arteries is of particular value. Palpation of the pulse in each individual case should be carried out in all points of the vessels accessible for palpation bilaterally. Only under this condition can a difference in the magnitude and nature of the pulse be detected. It should be noted that with tissue swelling or significantly pronounced subcutaneous fatty tissue, it is difficult to determine the pulse. The absence of pulsation in the arteries of the foot can not always be considered reliable sign circulatory disorders of the limb, since this is observed with anatomical variants of localization To.
Diagnosis of vascular diseases is considerably enriched by listening To. and recording phonograms. This method allows you to identify not only the presence of stenosis or aneurysmal expansion of the arterial vessel, but also their location. With the help of phonoangiography, the intensity of noises and their duration can be determined. New ultrasound equipment based on the Doppler phenomenon will also help in diagnosis.
With thrombolytic diseases To. limbs, it is very important to identify peripheral circulatory insufficiency. For this purpose various funkts, tests are offered. The most common of these are the Oppel test, the Samuels test and the Goldflam test.
Oppel's test: the patient in the supine position is asked to raise the lower limbs to an angle of 45 ° and hold them in this position for 1 minute; at insufficiency of peripheral circulation in the field of a sole appears blanching, a cut is absent normally.
Samuels test: the patient is asked to raise both extended lower limbs to an angle of 45 ° and perform 20-30 flexion-extensor movements in the ankle joints; blanching of the soles and the time of its onset indicate the presence and severity of circulatory disorders in the limb.
The Goldflam test is performed according to the same method as the Samuels test: the time of appearance of muscle fatigue on the side of the lesion is determined.
For specification of a condition of the valve device of veins also carry out funkts, tests. Insufficiency of the ostial (inlet) valve of the great saphenous vein of the leg is established using the Troyanov-Trendelenburg test. sick in horizontal position raises the lower limb until the saphenous veins are completely emptied. A rubber tourniquet is applied to the upper third of the thigh, after which the patient gets up. The harness is removed. In valvular insufficiency, dilated veins fill retrograde. For the same purpose, a Hackenbruch test is performed: in an upright position, the patient is asked to cough vigorously, while a push of blood is felt with the hand lying on the dilated vein of the thigh.
The patency of the deep veins of the lower extremities is determined by the Delbe-Perthes march test. In an upright position, the patient is placed with a rubber tourniquet in the upper third of the lower leg and asked to walk. If the superficial veins empty at the end of walking, the deep veins are patent. For the same purpose, you can apply a lobelin test. After elastic bandaging of the entire lower limb, 0.3-0.5 ml of 1% lobelin solution is injected into the veins of the rear of the foot. If within 45 sec. cough does not appear, the patient is asked to walk on the spot. If there is no cough for another 45 seconds. consider that deep veins are impassable.
The state of the valvular apparatus of the perforating veins of the lower leg can be judged by the results of the Pratt, Sheinis, Talman and five-flange tests.
Pratt's test: in a horizontal position, the patient's raised leg is bandaged elastic bandage, starting from the foot to the upper third of the thigh; a tourniquet is applied above; the patient gets up; without dissolving the tourniquet, they remove the previously applied bandage turn by turn and begin to apply another bandage from top to bottom, leaving gaps of 5-7 cm between the first and second bandages; the appearance of protrusions of the veins in these intervals indicates the presence of incompetent perforating veins.
Sheinis test: after applying three tourniquets to the raised leg, the patient is asked to walk; by filling the veins between the tourniquets, the localization of insufficient perforating veins is established.
Talman's test: one long rubber tourniquet is applied in the form of a spiral on an elevated leg with empty veins and the patient is asked to walk; the interpretation of the results is the same as with the Sheinis test.
Five tourniquet test: carried out in the same way, but with the imposition of two tourniquets on the thigh and three on the lower leg.
The specified wedge, tests are only qualitative. With their help, it is impossible to determine the amount of retrograde blood flow. Alekseev's method allows to establish it to some extent. The examined limb is raised up until the saphenous veins are completely emptied. In the upper third of the thigh, a Beer bandage is applied, squeezing both veins and arteries. The examined limb is lowered into a special vessel filled with warm water to the brim. At top edge The vessel has a drain pipe for draining the displaced water. After the limb is submerged, the amount of water displaced is accurately measured. Then remove the bandage and after 15 seconds. measure the amount of additionally displaced water, which is designated as the total volume of arteriovenous) inflow (V1). Then everyone repeats again, but about the cuff below the Beer bandage, supporting constant pressure 70 mmHg Art. (for compression of veins only). The amount of water displaced is defined as the volume of arterial inflow in 15 seconds. (V2). The volumetric velocity (S) of retrograde venous filling (V) is calculated by the formula:
S = (V1 - V2)/15 ml/sec.
From an extensive arsenal of instrumental methods used to examine patients with peripheral arterial disease, especially widely in angiol. practice uses arterial oscillography (see), reflecting the pulse fluctuations of the arterial wall under the influence of changing pressure in the pneumatic cuff. This technique allows you to determine the main parameters of blood pressure (maximum, average, minimum), to identify changes in the pulse (tachycardia, bradycardia) and heart rhythm disturbances (extrasystole, atrial fibrillation). Oscillography is widely used to determine the reactivity, elasticity of the vascular wall, its ability to expand, to study vascular reactions (Fig. 4). The main indicator in oscillography is the gradient of the oscillographic index, which, in the presence of vascular pathology, indicates the level and severity of the lesion.
According to the oscillograms obtained during the study of limbs on various levels, you can determine the place where a relatively high oscillatory index is observed, i.e., practically the place of narrowing of the vessel or thrombus. Below this level, the oscillatory index sharply decreases, since the movement of blood below the thrombus goes through collaterals, and pulse fluctuations become smaller or completely disappear and are not displayed on the curve. Therefore, for a more detailed study, it is recommended to record oscillograms at 6-8 different levels of both limbs.
At obliterating endarteritis there is a decrease in the amplitude of oscillations and the oscillatory index, primarily on the dorsal arteries of the feet. As the process develops, a decrease in the index is also observed on the lower leg (Fig. 4b). At the same time, the deformation of the oscillographic curve occurs, which in this case becomes stretched, the elements pulse wave in it are poorly expressed, and the top of the teeth acquires a vaulted character. The oscillatory index on the thigh, as a rule, remains within the normal range. With obstruction of the bifurcation of the aorta and arteries in the iliac-femoral zones, oscillography does not make it possible to determine the upper level of blockage of the vessel.
At an obliterating atherosclerosis in the field of an ileal or femoral zone patol, changes on an oscillogram arise mainly at measurement in proximal departments of extremities (fig. 4, c). A feature of the proximal forms of lesions of the arteries of the extremities is often the presence of two blocks, which can occur both on one or both of the same limbs only on different levels. Oscillography is more indicative of obstruction in the underlying segments (thigh, lower leg). It establishes the upper level of the lesion, but does not make it possible to judge the degree of compensation of the collateral circulation.
One of the methods of angiography is aortography (see). There are direct and indirect aortography. Among the methods of direct aortography, only translumbar aortography has retained its value - a method, with Krom, aorta puncture is performed by translumbar access and a contrast agent is injected directly through the needle (Fig. 14). Direct aortography techniques such as puncture of the ascending aorta, its arch and descending aorta thoracic aorta are not used in modern clinics.
Indirect aortography consists in the introduction contrast agent into the right side of the heart or into the pulmonary artery through a catheter and receiving the so-called. levograms. In this case, the catheter is passed into the right atrium, right ventricle or trunk of the pulmonary artery, where a contrast agent is injected. After passing it through the vessels of the small circle, the aorta is contrasted, the edges are fixed on a series of angiograms. The use of this method is limited due to the strong dilution of the contrast agent in the vessels of the pulmonary circulation and, therefore, insufficient "tight" contrasting of the aorta. However, in cases where it is impossible to perform retrograde aortic catheterization through the femoral or axillary arteries, it may be necessary to use this method.
Ventriculoaortography is a method of introducing a contrast agent into the cavity of the left ventricle of the heart, from where it enters the aorta and its branches with the natural blood flow. The injection of a contrast agent is carried out either through a needle, edges are entered percutaneously directly into the cavity of the left ventricle, or through a catheter, carried out from the right atrium by transseptal puncture of the interatrial septum into the left atrium and then into the left ventricle. The second way is less traumatic. These methods of contrasting the aorta are used extremely rarely.
The counter current method consists in percutaneous puncture of the axillary or femoral artery, passing the needle along the conductor retrograde to the blood flow into the vessel in order to better fix it and injecting a significant amount of a contrast agent under high pressure against the blood flow. For better contrast in order to reduce cardiac output the injection of a contrast agent is combined with the patient performing a Valsalva test. The disadvantage of this method is a strong overstretching of the vessel, which can lead to damage to the inner membrane and subsequent thrombosis.
Percutaneous catheterization aortography is used most often. The femoral artery is usually used to pass the catheter. However, the axillary artery may also be used. Through these vessels, catheters of a sufficiently large caliber can be inserted and, therefore, a contrast agent can be injected under high pressure. This makes it possible to more clearly contrast the aorta and adjacent branches.
For a research of arteries use an arteriography (see), edges it is made by a direct puncture of the corresponding artery and retrograde introduction of a contrast agent in its gleam or by percutaneous catheterization and a selective angiography. Direct puncture of the artery and angiography are performed mainly with contrasting of the arteries of the lower extremities (Fig. 15), less often - the arteries of the upper extremities, common carotid, subclavian and vertebral arteries.
Catheterization arteriography is performed with arteriovenous fistulas of the lower extremities. In these cases, the catheter is passed antegrade on the side of the lesion or retrograde through the contralateral femoral and iliac arteries until the aortic bifurcation and then antegrade along the iliac arteries on the side of the lesion and further in the distal direction to the required level.
For contrasting the brachiocephalic trunk, the arteries of the shoulder girdle and upper limbs, as well as the arteries of the thoracic and abdominal aorta, transfemoral retrograde catheterization is more indicated. Selective catheterization requires the use of catheters with a specially designed beak or the use of guided systems.
Selective arteriography gives the most complete picture of the angioarchitectonics of the studied basin.
In the study of the venous system, puncture vein catheterization is used (see Puncture venous catheterization). It is carried out according to the Seldinger method by percutaneous puncture of the femoral, subclavian and jugular veins and the catheter through the blood flow. These accesses are used for catheterization of the superior and inferior vena cava, hepatic and renal veins.
Vein catheterization is carried out in the same way as arterial catheterization. Injection of a contrast agent due to the lower blood flow velocity is performed at a lower pressure.
Contrasting the system of the superior and inferior vena cava (see Cavography), renal, adrenal and hepatic veins is also carried out by catheterization.
Phlebography of the extremities is performed by introducing a contrast agent through the blood flow through a puncture needle or through a catheter inserted into one of the peripheral veins by venosection. There is a distal (ascending) phlebography, retrograde femoral phlebography, pelvic phlebography, retrograde phlebography of the leg veins, retrograde orocavography. All studies are carried out by intravenous administration of radiopaque preparations (see Phlebography).
Usually for contrasting of veins of the lower extremities puncture or expose a back vein of a thumb or one of back metatarsal veins, enter a catheter into to-ruyu. To prevent the flow of a contrast agent into the superficial veins of the leg, the legs are bandaged. The patient is transferred to a vertical position and injected with a contrast agent. If a contrast agent is injected against the background of the Valsalva maneuver, then with moderate valvular insufficiency, reflux of the contrast agent into the femoral vein may occur, and with severe valvular insufficiency, reflux of the contrast agent may reach the veins of the leg. The X-ray image of the veins is fixed using a series of radiographs and the X-ray cinematography method.
Many changes in K. page. are inherently compensatory-adaptive. These include, in particular, atrophy of arteries and veins, manifested by a decrease in the number of contractile elements in their walls (mainly in the middle shell). Such atrophy can develop both on a physiological (involution of the arterial duct, umbilical vessels, venous duct in the postembryonic period), and on a pathological (desolation of arteries and veins when they are compressed by a tumor, after ligation) basis. Quite often adaptive processes are shown by a hypertrophy and a hyperplasia of smooth muscle cells and elastic fibers of walls To. page. Elastosis and myoelastosis of arterioles and small arterial vessels of the systemic circulation can serve as an illustration of such changes. hypertension and in many respects a similar restructuring of the structure of the arteries of the lungs with hypervolemia of the pulmonary circulation, which occurs with some congenital heart defects. Of exceptionally great importance in the restoration of hemodynamic disturbances in organs and tissues is increased collateral circulation, accompanied by recalibration and neoplasm To. in a zone patol, obstacles to a blood-groove. The “arterialization” of veins also belongs to adaptive manifestations, for example, in arteriovenous aneurysms, when in the place of an anastomosis the veins acquire a gistol, a structure approaching the structure of the arteries. The adaptive essence is carried also by changes in arteries and veins after creation of artificial vascular anastomoses (arterial, venous, arteriovenous) with to lay down. purpose (see Shunting of blood vessels). In the hemomicrocirculation system, adaptive processes are morphologically characterized by neoplasm and restructuring of terminal vessels (precapillaries into arterioles, capillaries and postcapillaries into venules), increased blood flow from the arteriolar to the venular section with an increase in the number of arteriovenular shunts, hypertrophy and hyperplasia of smooth muscle cells in precapillary sphincters, the closure of which prevents the flow of excess amounts of blood into the capillary networks, an increase in the degree of tortuosity of arterioles and precapillaries with the formation of loops, curls and glomerular structures along their course (Fig. 19), contributing to the weakening of the force of the pulse impulse in the arteriolar link of the microvasculature.
Extremely various morfol. changes occur during autotransplantation, allotransplantation and xenotransplantation To. using autologous, allogeneic and xenogenic vascular grafts, respectively. Thus, in venous autografts transplanted into arterial defects, the processes of organizing graft structures that lose their viability with their replacement by connective tissue and the phenomena of reparative regeneration with the formation of elastic fibers and smooth muscle cells, culminating in the “arterialization” of the autovein, develop. In the case of replacement of an arterial vessel defect with a lyophilized allogeneic artery, a “sluggish” rejection reaction occurs, accompanied by a gradual destruction of the graft, the organization of a dead tissue substrate, and regenerative processes leading to the formation of a new vessel, characterized by the predominance of collagen fibrils in its walls. With plastic K. s. with the help of synthetic prostheses (explantation), the walls of the latter are covered with a fibrinous film, germinate with granulation tissue and undergo encapsulation with endothelization in their subsequent inner surface (Fig. 20).
Changes To. with age reflect processes of their fiziol, postembryonic growth, adaptation to the conditions of a hemodynamics changing during a life and senile involution. Senile vascular changes in general view are shown by an atrophy in walls of arteries and veins of contractile elements and reactive growth of connective tissue, hl. arr. in the inner shell. In the arteries of the elderly, involutive sclerotic processes are combined with atherosclerotic changes.
Pathology
Malformations of blood vessels
Malformations of blood vessels, or angiodysplasia, are congenital diseases that manifest themselves as anatomical and functional disorders of the vascular system. In the literature, these defects are described under various names: branched angioma (see Hemangioma), phlebectasia (see Angiectasia), angiomatosis (see), phlebarteriectasia, Parks Weber syndrome (see Parks Weber syndrome), Klippel-Trenaunay syndrome, arteriovenous angioma etc.
Malformations To. occur in 7% of cases of patients with other congenital vascular diseases. The vessels of the extremities, neck, face, and scalp are most often affected.
Proceeding from anatomic and morfol. signs of malformations To. can be divided into the following groups: 1) vein malformations (superficial, deep); 2) malformations of arteries; 3) arteriovenous defects (arteriovenous fistulas, arteriovenous aneurysms, arteriovenous vascular plexuses).
Each of the above types of angiodysplasia can be single or multiple, limited or widespread, combined with other malformations.
The etiology has not been completely elucidated. Consider that for formation of defect To. a number of factors matter: hormonal, tempera
round, fetal injury, inflammation, infection, toxicosis. According to Malan and Puglionisi (E. Malan, A. Puglionisi), the occurrence of angiodysplasia is the result of a complex violation of the embryogenesis of the vascular system.
Malformations of the superficial veins are the most frequent and account for 40.8% of all angiodysplasias. Either only the saphenous veins are involved in the process, or it spreads to deeper tissues and affects the veins of the muscles, intermuscular spaces, and fascia. There is a shortening of the bones, an increase in the volume of soft tissues. Localization of the defect - upper and lower limbs.
Morphologically, the defect is manifested by a number of structural features that are pathognomonic for this species. Some of them include angiomatous complexes with smooth muscle fibers in the walls of blood vessels; others are represented by ectatic, thin-walled veins with an uneven lumen; the third are sharply dilated muscle-type veins, in the walls of which a chaotic orientation of smooth muscles is found.
Rice. Fig. 22. The lower limbs of a 2.5-year-old child with a malformation of the deep veins of the limbs (Klippel-Trenaunay syndrome): the limbs are enlarged, edematous, there are extensive vascular spots on the skin, the subcutaneous veins are dilated.
Rice. 23. Bottom part face and neck of a 6-year-old child with phlebectasia of the internal jugular veins: spindle-shaped formations on the front surface of the neck, more on the left (the picture was taken at the moment of the patient's tension).
Rice. Fig. 24. The lower limbs of a 7-year-old child with right-sided congenital arteriovenous defects: the right limb is enlarged in size, the saphenous veins are dilated, there are pigment spots in some parts of the limb (the limb is in a forced position due to contracture).
Clinically, the defect is manifested by varicose veins. The expansion of the veins is different - stem, nodal, in the form of conglomerates. Often there are combinations of these forms. The skin over the dilated veins is thinned, bluish in color. The affected limb is enlarged in volume, deformed, which is associated with blood overflow of dilated venous vessels (Fig. 21). The characteristic signs are the symptoms of emptying and sponges, the essence of which is to reduce the volume of the affected limb at the time of its lifting up or when pressing on the dilated venous plexuses as a result of emptying the vicious vessels.
On palpation, tissue turgor is sharply reduced, movements in the joints are often limited due to bone deformation, dislocations. There are constant severe pain, trophic disorders.
Phlebograms show dilated, deformed veins, accumulation of a contrast agent in the form of shapeless spots.
Treatment is possibly complete removal damaged tissues and blood vessels. In particular severe cases when radical treatment is impossible, patol, formations are partially excised and multiple stitching of the remaining altered areas is performed with silk or nylon sutures. With a widespread lesion, surgical treatment should be carried out in several stages.
Deep vein malformations appear congenital disorder blood flow through the main veins. They occur in 25.8% of all angiodysplasia cases. The defeat of the deep veins of the extremities is described in the literature as the Klippel-Trenaunay syndrome, which for the first time in 1900 gave a characteristic wedge, a picture of this defect.
Morfol, the study of the defect allows us to distinguish two variants of the anatomical "block": the dysplastic process of the main vein and its external compression due to the disorganization of the arterial trunks, muscles, as well as fibrous cords, tumors. The histoarchitectonics of the saphenous veins indicates the secondary, compensatory nature of ectasias.
Klippel-Trenaunay syndrome is observed only on the lower extremities and is characterized by a triad of symptoms: varicose saphenous veins, an increase in the volume and length of the affected limb, pigment or vascular spots (Fig. 22). Patients complain of heaviness in the limbs, pain, fatigue. Constant signs are hyperhidrosis, hyperkeratosis, ulcerative processes. To accompanying symptoms include bleeding from the intestines and urinary tract, deformities of the spine and pelvis, joint contractures.
In the diagnosis of defect, the leading role belongs to phlebography, which reveals the level of the block of the main vein, its length, the condition of the saphenous veins, for which the identification of embryonic trunks along the outer surface of the limb and along the sciatic nerve is considered a characteristic sign of the defect.
Treatment is associated with certain difficulties. Radical treatment with normalization of blood flow is possible with external compression of the vein and consists in eliminating the blocking factor. In cases of aplasia or hypoplasia, restoration of blood flow by plasty of the main vein is indicated, however, such operations are associated with the risk of graft thrombosis. It should be emphasized that attempts to remove dilated saphenous veins with unrestored blood flow through the main veins are fraught with the risk of severe venous insufficiency in the limb and its death.
Congenital phlebectasia of the jugular veins account for 21.6% of other vascular malformations.
Morfol, the picture is characterized by a pronounced underdevelopment of the muscular-elastic frame of the vein wall up to its complete absence.
Clinically defect is shown by emergence at the patient on a neck during shout, tension of tumorous education (fig. 23), a cut in a normal state disappears and is not defined. With phlebectasia of the internal jugular veins, the formation has a fusiform shape and is located in front of the sternocleidomastoid muscle. Phlebectasia of the saphenous veins of the neck have a rounded or stem shape and are well contoured under the skin. With phlebectasia of the internal jugular veins accompanying signs there is hoarseness of voice, shortness of breath. Complications of the defect include wall ruptures, thrombosis and thromboembolism.
Treatment of patients is only surgical. With phlebectasia of the saphenous veins, excision of the affected areas of the vessels is indicated. In phlebectasia of the internal jugular veins, the method of choice is to strengthen the vein wall with an implant.
Defects of arterial peripheral vessels are observed extremely rarely and are expressed in the form of narrowing or aneurysm-like expansions of the arteries. Wedge, a picture of these vices and surgical tactics do not differ from those in acquired lesions of the arteries.
Arteriovenous defects are manifested by congenital arteriovenous communications in the form of fistulas, aneurysms, and vascular plexuses. Compared with other angiodysplasias, arteriovenous defects are less common and occur in 11.6% of cases. They can be observed in all organs, however, the limbs are most often affected, have a local or widespread character.
Typical morfol. change from K. page. is their restructuring in the form of "arterialization" of the veins and "venization" of the arteries.
The wedge, the picture of congenital arteriovenous defects consists of local and general symptoms.
To local symptoms include: hypertrophy of the affected organ, osteomegaly, varicose veins and pulsation of the saphenous veins, pigmented or vascular spots (Fig. 24), increased pulsation of the main vessels, local hyperthermia, trophic skin disorders, systole-diastolic murmur with an epicenter over the patol area, shunt. Common symptoms are: tachycardia, arterial hypertension, pronounced changes in heart function. Constant ulcerative and necrotic processes, often accompanied by bleeding.
Examination of patients reveals a pronounced arterialization) of venous blood. At an arteriography it is possible to reveal an arrangement "patol, educations. Characteristic angiographic signs of defect are: simultaneous filling by a contrast agent of arteries and veins, impoverishment of a vascular drawing distal fistulas, accumulation of a contrast agent in places of their localization.
Treatment consists in elimination patol, communications between arteries and veins by bandaging and intersection of fistulas, removal of aneurisms, excision of arteriovenous textures within healthy fabrics. With diffuse lesions of the vessels of the extremities, the only radical method of treatment is amputation.
Damage
Injuries To. more common in wartime. So, during the Great Patriotic War (1941 -1945) damage to the main K. with. met in 1% of the wounded. Isolated injuries of arteries accounted for 32.9%, and veins - only 2.6%, combinations of damage to arteries and veins - 64.5%. Classification of gunshot wounds To. developed in the same period (Table 1). Quite often damages of vessels are combined with fractures of bones, an injury of nerves that burdens a wedge, a picture and the forecast.
In peacetime practice, injuries and damage to arteries and veins amount to approx. 15% of all emergency pathology To. The majority of damages To. occurs as a result of accidents in transport, knife and less often gunshot wounds.
Damage to the arteries is divided into closed and open. The closed damages To. pages, in turn, divide into contusions when there is damage only to an internal cover of a vessel, and gaps at which there is a damage of all three layers of a wall. With ruptures and injuries of the artery, blood is poured into the surrounding tissues and a cavity is formed that communicates with the lumen of the vessel (Fig. 25) pulsating hematoma (see). When the artery is injured, the pulsation distal to the injury site is weakened or completely absent. In addition, the phenomena of ischemia of the area are observed, to-ruyu this artery feeds (see Ischemia), and the degree of ischemia can be different, and therefore has a different effect on the fate of the limb (Table 2), up to the development of gangrene (see) .
Each wound To. it is followed by bleeding (see), the K-roe can be primary (at the moment of injury of a vessel or immediately after it), and secondary, a cut, in turn, is divided into early and later. Early secondary bleeding occurs during the first day after injury and may be the result of an increase in blood pressure, improved blood circulation, etc. Late secondary bleeding that develops after 7 or more days may occur as a result of infection of the wound passing to the wall of the K.s. The cause of secondary bleeding can also be foreign bodies that are close to the wall of the K.s.
Diagnosis of damage to the main To. in most cases it is put on the basis of the expressed wedge, pictures, especially at lateral wounds. It is more difficult to recognize complete ruptures of the vessel, since the screwing of the inner lining of the artery contributes to the spontaneous arrest of bleeding, and due to the divergence of the ends of the artery, these injuries are often not recognized even during surgical treatment of the wound. The greatest number of diagnostic errors occurs with closed vascular injuries. With such injuries, only the inner and middle shells of the vessel are often damaged with impaired blood flow, which is not always easy to recognize even when the vessel is inspected during surgery. In some cases, especially when closed injury, there is a need for arteriography, edges allows you to identify the nature, prevalence and localization of damage, as well as choose the method of surgical treatment and its volume. The diagnosis of spasm or compression of the artery should also be substantiated by arteriography or revision of the vessel during surgery. wound treatment.
The first action at treatment of wounds To. is a temporary stop of bleeding. For this purpose use a pressure bandage (see), pressing To. throughout with the help of a finger, closing the hole in the wound with fingers inserted into the wound according to N. I. Pirogov, applying a demeure clamp and tamponade of the wound with gauze swabs (see Tamponade). In addition, general hemostatic agents (10% chloride solution calcium, vitamin K, fibrinogen, etc.).
After applying one of the temporary methods of stopping bleeding, in most cases there is a need for a final stop of bleeding. The methods of the final stop of bleeding include: ligation of the artery in the wound or throughout and the imposition of a vascular suture (see) or a patch on a defect in the artery wall. Two facts established by domestic surgeons during the Second World War should be taken into account: ligation of the main arteries of the extremities in 50% of cases led to their gangrene, and reconstructive operations, in particular, vascular suture, were possible only in 1% of operations on vessels.
In peacetime, surgical treatment should be aimed at restoring the main blood flow. An effective restorative operation can be performed in case of trauma To. at different times: from several hours to several days. The possibility of surgical intervention should be judged by the state and changes in tissues in the area of ischemia and damage. Recovery operations for trauma To. can be extremely varied. The main type of surgical intervention in case of damage to the arterial trunks is a manual lateral or circular suture; At complication of an injury To. widespread thrombosis, it is necessary to pre-produce thrombectomy (see) from the central and distal ends of the damaged artery. With combined damage to large arterial and venous trunks, one should strive to restore the patency of both K. s. This is especially important in severe limb ischemia. Ligation of the main vein under such conditions, even with the restoration of full arterial blood flow, significantly contributes to the regression of ischemia and, causing venous blood stasis, can lead to thrombosis in the arterial suture. In case of arterial injuries accompanied by a large tissue defect, the replacement of the artery defect with a synthetic corrugated prosthesis or autovein is used (Fig. 26 and 27).
Staged treatment
In military field conditions, the first medical aid on the battlefield (in the lesion) in cases of external bleeding is reduced to its temporary stop. Stopping bleeding begins with finger pressing of the vessels in typical places, then a pressure bandage is applied. If bleeding continues, a tourniquet is applied (see Hemostatic tourniquet). In the absence of fractures, forced flexion of the limb can be used, the edges should be bandaged to the body.
First aid includes control and change of tourniquets from improvised means to standard ones.
At the first medical care(PMP) the wounded with continued bleeding, with bandages soaked in blood, and with tourniquets are sent to the dressing room. Apply the following ways to temporarily stop bleeding: applying a pressure bandage; tamponade of wide wounds, if possible, stitching the edges of the skin over the tampon, followed by the application of a pressure bandage; clamping the vessel visible in the wound, and its subsequent ligation; if it is impossible to stop the bleeding by the listed methods, a tourniquet is applied. Under the tourniquet on the limb on the side opposite to the location of the vascular bundle, a plywood tire wrapped with cotton should be placed. Above the level of the tourniquet, local anesthesia is performed (conduction or case blockade). Enter analgesics. After a temporary stop of bleeding, immobilization is used. Upon admission of the wounded with tourniquets, the validity and correctness of their application are monitored: novocaine blockade is performed above the tourniquet, the vessel above the tourniquet is pressed with fingers, the tourniquet is slowly relaxed. With the resumption of bleeding, you should try to stop it by the listed methods without the use of a tourniquet; if this fails, then the tourniquet is applied again. All harnesses from improvised means are replaced with service ones. If, after removing the tourniquet, the bleeding does not resume, then a pressure bandage is applied to the wound, and the tourniquet is left on the limbs untightened (provisional tourniquet). With rigor mortis of the muscles of the limb, removal of the tourniquet is contraindicated.
All wounded with temporarily stopped bleeding are subject to evacuation in the first place.
With qualified assistance (MSB), in the process of medical sorting, the following groups of the wounded are identified: with applied tourniquets; with severe blood loss; with uncompensated ischemia; with compensated ischemia.
With a minimum and reduced amount of assistance, the wounded are sent to the dressing room with tourniquets, massive blood loss and uncompensated limb ischemia. Antishock measures in this group are usually carried out in parallel with surgical treatment.
With full assistance, all those admitted with vascular injuries are sent to the dressing room, except for the wounded with compensated ischemia without a history of bleeding, who are expedient to be sent to hospital facilities in the first place for assistance.
If the limb is in a state of rigor mortis due to the imposition of a tourniquet, it is subject to amputation at the level of the tourniquet.
When providing qualified assistance, the final stop of bleeding is shown with the restoration of the patency of the vessel by suturing (under appropriate conditions).
In the conditions of a difficult medical and tactical situation, as well as in the absence of surgeons who own the technique of a vascular suture, it is necessary to ligate the vessel with a number of precautions to avoid gangrene of the limb (see Vascular collaterals, Ligation of blood vessels). The ligation of the vessel is also allowed in case of its large defects, requiring long labor-intensive plastic surgeries.
In hospitals in the process of honey. sorting reveal the following categories of the wounded: 1) wounded with restored vessels, the Crimea continues treatment, and at indications make repeated recovery operations; 2) the wounded with dead limbs, the Crimea determine the level of necrosis and truncate the limb; 3) wounded with temporarily stopped or self-stopped bleeding, in which the vessels, when providing qualified assistance, were not restored due to the conditions of the situation; they are undergoing remedial operations.
Restorative operations are contraindicated in the general serious condition of the wounded, with the development of a wound infection, in the midst of radiation sickness.
In hospitals, the wounded are also operated on for secondary bleeding, festering hematomas and aneurysms (mainly the vessel is ligated throughout).
Operations for traumatic aneurysms (hematomas), as well as the restoration of ligated vessels, should be performed as soon as possible. early dates, because in the future due to the development of collaterals distal of the damaged vessel narrows sharply, as a result of which the restoration of the main blood flow often becomes impossible, while the collaterals are destroyed during excision of the aneurysm and the blood circulation of the limb deteriorates sharply.
During surgery for vascular injuries different localization it is necessary to remember a number of anatomical and a wedge, features which knowledge will allow to avoid occurrence of serious complications.
Damage to the subclavian vessels is often combined with trauma to the brachial plexus, which often leads to diagnostic errors, since movement and sensitivity disorders due to ischemia are regarded as an injury to the nerve trunks. In order to avoid massive bleeding that is difficult to stop, in order to create a good operative access, it is necessary to cross or resect a part of the clavicle for the duration of the operation, followed by its implantation.
At wounds of axillary vessels it is necessary to examine carefully all veins, and the damaged venous trunks in order to avoid an air embolism (see) or a thromboembolism (see) to bandage.
The brachial artery has an increased propensity for prolonged spasm compared to other arteries, which can sometimes cause no less serious circulatory disorders of the limb than with a complete interruption of the artery. During operations on this vessel, mandatory local application of novocaine and papaverine is necessary.
If one of the arteries of the forearm is injured, there is no need for a reconstructive operation, the ligation of the vessel is safe.
Extensive damage to the iliac arteries most often requires alloplasty. It is advisable, unlike operations on other segments, to strive to restore the iliac veins, since in this anatomical region there are not always sufficient detours of blood outflow.
Damage to the femoral artery is most dangerous in the zone of the adductor (Hunter's) canal and often leads to gangrene of the limb. With simultaneous damage to the femoral and great saphenous veins, it is necessary to restore one of the venous outflow collectors.
Damage to the popliteal artery in 90% of patients is accompanied by gangrene of the lower leg. Along with the emergency restoration of the artery, it is advisable to restore the damaged vein, since venous stasis contributes to the development of severe ischemic tissue edema, which can cause re-ischemia after the restoration of arterial patency. To avoid this complication, the restoration of the popliteal vessels in uncompensated ischemia should end with the dissection of the fascial sheaths of the leg muscles.
Damage to the arteries of the lower leg is usually accompanied by a spasm that extends to the entire arterial network of the segment. In such cases, the use of antispasmodics is indicated, and with an unremovable spasm - fasciotomy.
The literature discusses the technique of temporary vascular prosthetics, which, according to some authors, can allow the restoration of blood vessels in two stages: at the stage of qualified assistance, the restoration of blood flow with the help of temporary prosthesis and at the stage of rendering specialized care final restoration of the vessel. It is difficult to count on the successful implementation of this method, since the exposure of the damaged ends of the vessel and their processing for effective prosthetics require such a degree of skill from the surgeon, which also allows restoration of the vessel. In addition, temporary prosthetics during a long evacuation may be complicated by thrombosis of the prosthesis, prolapse of the end of the prosthesis from the vessel and resumption of bleeding. However, temporary prosthetics is undoubtedly an appropriate measure during a reconstructive operation, since it allows to reduce the duration of ischemia, restore normal color tissues and provide a more radical treatment of the wound.
(see), post-thrombotic disease, varicose veins (see). In surgical practice, most often there are patients suffering from atherosclerotic lesions of the aorta and large main arteries of the extremities, as well as organ vessels (renal, mesenteric and celiac arteries). The defeat of the main arteries of the extremities is accompanied by ischemia of the corresponding area, characterized by pallor of the skin, pain, limited mobility and trophic disorders, which in some cases turn into gangrene (see).
constriction carotid arteries leads to cerebral ischemia. The severity of the manifestation of the disease and its prognosis depend on which artery is switched off from the bloodstream, as well as on the degree of development of collateral circulation.
The narrowing of the renal artery due to atherosclerosis, arteritis or fibromuscular dysplasia is accompanied by persistent arterial hypertension (see Arterial hypertension), which is sometimes malignant in nature (renovascular hypertension) and not amenable to conservative treatment.
Narrowing of the vessels of the mesentery is accompanied by a clinic of abdominal angina with sharp pains in the stomach and dyspeptic disorders(see. Abdominal toad).
Acute thrombosis or embolism of the arterial trunks of the extremities or the terminal aorta is accompanied by signs of acute ischemia of the extremities. Embolism is more often observed in women, acute thrombosis - in men due to their greater susceptibility to atherosclerotic lesions of the arteries. Acute thromboses and embolisms often affect the bifurcation of the aorta and the vessels of the lower extremities; vessels of the upper extremities are much less often affected.
Post-thrombotic disease is a disease that develops as a result of a deep vein thrombosis. Morfol, its basis is structural lesions of deep veins in the form of re-canalization or their occlusion. In the pathogenesis of post-thrombotic disease, disturbances in venous blood return due to perverted blood flow through deep, perforating and superficial veins, microcirculatory shifts and insufficient lymph circulation play a role. According to the wedge, the picture distinguishes edematous, edematous-varicose, varicose-trophic and trophic forms. There are stages of compensation, sub-compensation and decompensation. The diagnosis is made on the basis of anamnestic data, a wedge, symptoms and phlebographic studies. The course is chronic. Indications for surgical treatment are trophic changes in the skin and secondary varicose veins of the superficial veins, subject to recanalization of the deep veins of the leg. It consists in total or subtotal ligation of the perforating veins of the lower leg, supplemented by the removal of only varicose veins. Segmental lesions of the iliac and femoral veins may be an indication for bypass shunting and replacement surgery for the edematous form of the disease. Regardless of the operation performed, it is necessary to continue conservative treatment; physiotherapeutic procedures, elastic compression, drug therapy, dignity. treatment.
Tumors
Tumors (angiomas) repeat the structure of vessels - arteries, veins, capillaries, or are derived cells that form special structures in the vascular walls.
Vascular tumors occur at any age regardless of gender. Their localization is different: skin, soft tissues, internal organs, etc. In the development of vascular tumors, great importance is attached to dysembryoplasia in the form of splitting off of angioblastic elements, which in the embryonic period or after birth begin to proliferate, forming malformed vessels of different structures. Tumors develop on the basis of these dysembryoplasias or without connection with them.
There are benign tumors: hemangioma (see), endothelioma (see), differentiated hemangiopericytoma (see), glomus tumors (see), angiofibroma (see) and malignant: malignant angioendothelioma (see), malignant (undifferentiated) Hemangiopericytoma .
A wedge, displays depend on the sizes and localization of a tumor. Malignant tumors give hematogenous metastases.
Treatment is surgical, cryotherapy, radiation.
Operations
In the 20th century vascular surgery achieves significant success, which is associated with the introduction of special instruments into practice, the improvement of the vascular suture (see), the development of radiopaque research methods, and the creation of specialized institutions. Common to all operations on K. s., in addition to normal conditions necessary for any intervention are measures that prevent bleeding and other dangerous consequences - thrombosis K. s., ischemic changes in the tissues of a limb, organ or area of the body that are supplied with blood through this vascular highway. In this regard, the method of preparing the patient for surgery and the features of postoperative management. Dangerous consequences of blood loss are prevented by blood transfusion (see) into a vein or artery. Therefore during each operation on To. it is necessary to have a supply of preserved blood and blood-substituting fluids (see).
Since, along with the dangers of bleeding and the consequences of blood loss (see) during operations on K. s. possible occurrence of a thrombus in the lumen of the vessel and embolism, it is necessary to determine the parameters of blood coagulation before and after surgery. In case of increased blood clotting, anticoagulants should be prescribed in the preoperative period.
At operations on To. apply various methods of anesthesia, but most often inhalation anesthesia (see). For special indications, use
Rice. Fig. 28. Schematic representation of operations to restore the main blood flow in case of segmental occlusion of the arteries: a - bypass shunting; b - endarterectomy; c - resection of the blocked segment of the artery with its prosthesis (1 - section of the artery clogged with a thrombus, 2 - graft, 3 - dissected section of the artery, 4 - removed section of the artery).
Indications for operations on K. s. are diverse, but segmental occlusions of the arteries with the patency of the vessel above and below the site of blockage are most often indications for operations on the arteries. Other indications are injuries to K. with., their tumors, varicose veins, pulmonary embolism, etc. Restoration of the main blood flow is achieved by resection of the clogged segment of the artery with its prosthesis, bypass shunting and endarterectomy (Fig. 28).
For prosthetics To. autovein and synthetic prostheses are widely used. The disadvantage of an autovein is its low suitability for prosthetics of large-caliber arteries due to the lack of veins of the appropriate diameter that could be resected without great damage to the body. Besides, gistol, researches in the remote postoperative period showed that the autovein sometimes undergoes connective tissue degeneration, which can cause thrombosis of the vessel or the formation of an aneurysm.
The use of synthetic prostheses has fully justified itself in prosthetics of the aorta and arteries of large diameter. When prosthetics of arterial vessels of smaller diameter (femoral and popliteal arteries), the results were much worse, because in these areas there are more favorable conditions for the occurrence of thrombosis. In addition, the lack of proper elasticity and extensibility of the prosthesis leads to frequent thrombosis, especially if the graft crosses the joint line.
Another type of intervention aimed at restoring the main blood flow is endarterectomy. The first endarterectomy was made by R. Dos Santos (1947). Endarterectomy methods can be conditionally divided into closed, semi-open and open. The method of closed endarterectomy is that the operation is performed with a special tool from a transverse section of the artery. A semi-open endarterectomy is the removal of the inner lining from several transverse incisions in an artery. Open endarterectomy involves the removal of the modified inner membrane through a longitudinal arteriotomy over the site of occlusion.
Endarterectomy by the eversion method has been introduced into practice, the essence of which is that after the artery is isolated and the site of occlusion is crossed distally, atherosclerotic plaques are exfoliated with a special tool along with the changed inner membrane, the outer and middle membranes are turned inside out to the end of the plaque. After that, the artery is screwed back again and anastomosed with a circular manual or mechanical suture. The indication for this method of endarterectomy is segmental atherosclerotic occlusion of insignificant extent.
In case of widespread atherosclerotic occlusions without pronounced destruction of the vessel walls, endarterectomy is performed using the eversion method, followed by reimplantation of the vessel. In this case, the entire affected area of the arterial trunk is resected. Next, endarterectomy is performed using the eversion method. After reverse screwing of the artery, the formed autograft is checked for tightness and end-to-end is sutured back to its original place by two anastomoses.
Significant extent of occlusion with wall destruction (calcification, ulcerative atheromatosis), arteritis or vessel hypoplasia are indications for autotransplantation with explantation. With this method, a transplant is used, consisting of a synthetic prosthesis, and in places of fiziol, folds, for example, under the inguinal ligament, an autoartery is located. The main advantage of this method is that in the place of the greatest traumatization of the vessel (hip, knee, shoulder joints) does not pass through the alloprosthesis, but through the autoartery.
The issues of surgical treatment of arterial hypertension associated with occlusive lesions of the renal arteries are being widely developed. The choice of surgical intervention for this disease depends on the cause and nature of the lesion. The method of transortal endarterectomy is applicable only for atherosclerosis, when there is a segmental lesion of the mouth of the renal arteries. Since atherosclerosis is the most common cause of renovascular hypertension, this method finds the most wide application. With fibromuscular dysplasia, since patol, the process can be of a diverse nature (tubular, multifocal, etc.), range surgical interventions much wider and includes auto-arterial replacement of the renal artery, its resection with end-to-end anastomosis, and reimplantation of the renal artery orifice. With a widespread lesion of the renal artery on the basis of arteritis, the most expedient operations remain resection of the renal artery with its prosthesis and aortorenal bypass surgery. An autoarterial graft from the deep femoral artery is used as a plastic material.
Reconstructive operations on the branches of the aortic arch are one of the new and unique types of vascular surgery. Segmental occlusions located in the proximal parts of the arterial bed are the most accessible for surgical correction. The main type of reconstruction for both stenosis and complete blockage of the brachiocephalic branches is endarterectomy.
Resection of the affected area of the artery with its plasty is permissible only in the initial sections of the innominate, common carotid and subclavian arteries (before branches depart from them). For the success of surgical treatment of this pathology, it is of great importance right choice operational access to the branches of the aortic arch.
Methods of operations on the veins and their features are given in special articles (see Varicose veins, Ligation of blood vessels, Thrombophlebitis, Phlebothrombosis).
In the postoperative period, the most important measures are the prevention of inflammatory complications, thrombosis and embolism. Anticoagulants (most often heparin) are used 24 hours after surgery. Heparin is administered intravenously at a dose of 2500-3000 IU every 4-6 hours. within 3-5 days. It is desirable to maintain the blood coagulation time according to Burker within 7-8 minutes.
Results of surgical treatment of wounds and diseases To. generally favorable.
In the treatment of congenital anomalies To. (aneurysms, arteriovenous anastomoses) almost no lethality and ischemic complications occur, which is associated with adequate development of collateral circulation in these cases and good development of surgical intervention methods.
The results of surgical treatment of benign tumors To. depend on the location and extent of the lesion. Complete cure of extensive skin hemangiomas in some cases can not be achieved. Surgical treatment malignant angiomas cannot be considered satisfactory due to rapid growth, recurrence and metastasis. The results of treatment of endarteritis depend on the severity of the process. Treatment of thrombophlebitis in connection with the introduction of active anticoagulants and improvement surgical methods improved significantly.
Further progress vascular surgery largely depends on the introduction of new methods into practice early diagnosis diseases To. and improvement operational methods treatment, and first of all microsurgery (see).
tables
Table 1. CLASSIFICATION OF GUN SHOT WOUNDS OF THE VESSELS BY THE TYPE OF THE DAMAGED VESSEL AND THE CLINICAL NATURE OF THE WOUND (from the book "The experience of Soviet medicine in the Great Patriotic War 1941 - 1945")
|
1. Wounded artery |
a) without primary bleeding and pulsating hematoma (vascular thrombosis) b) accompanied by primary arterial bleeding c) with the formation of a pulsating arterial hematoma (aneurysm) |
|
2. Wounded vein |
a) without primary bleeding and hematoma (vascular thrombosis) b) accompanied by primary venous bleeding c) with the formation of a venous hematoma |
|
3. Injury to an artery along with a vein |
a) without primary bleeding and pulsating hematoma (vascular thrombosis) b) accompanied by primary arteriovenous bleeding c) with the formation of a pulsating arteriovenous hematoma (aneurysm) |
|
4. Separation or crushing of the limb with damage to the neurovascular bundle |
Table 2. CLASSIFICATION, DIAGNOSIS, PROGNOSIS AND TREATMENT OF ISCHEMIA IN LIMB VESSEL INJURIES (according to V. A. Kornilov)
|
Degree of ischemia |
Main clinical signs |
||
|
Compensated (due to roundabout blood flow) |
Active movements, tactile and pain sensitivity are preserved |
There is no threat of gangrene of the limb |
There are no indications for urgent restoration of the vessel. Vessel ligation is safe |
|
Uncompensated (roundabout blood flow is insufficient) |
Loss of active movements, tactile and pain sensitivity occurs 72 - 1 hour after injury |
The limb dies within the next 6-10 hours. |
Emergency vascular repair indicated |
|
irreversible |
Rigor mortis develops in the limb muscles |
Gangrene of the limb. Impossible to save a limb |
Amputation shown. Restoration of the vessel is contraindicated - death from toxemia is possible |
Bibliography:
Anatomy- Vishnevsky A. S. and Maksimenkov A. N. Atlas of the peripheral nervous and venous systems, L., 1949; Grigoryeva T. A. Innervation of blood vessels, M., 1954, bibliogr.; Dogel I. M. Comparative anatomy, Physiology and Pharmacology of Blood and Lymphatic Vessels, vol. 1-2, Kazan, 1903 -1904; D about l-go-Saburov B. A. Essays on the functional anatomy of the vascular system, L., 1961, bibliogr.; Kupriyanov V. V. Ways of microcirculation, Chisinau, 1969, bibliogr.; Chernukh A. M., Aleksandrov P. N. and Alekseev O. V. Microcirculations, M., 1975, bibliogr.; Angiology, hrsg. v. M. Ratschow, Stuttgart, 1959; Blood vessels and lymphatics, ed. by D. I. Abramson, N. Y.-L., 1962; Cliff W. J. Blood vessels, Cambridge, 1976, bibliogr.; The peripheral blood vessels, ed. by J. L. Orbison a. D. E. Smith, Baltimore, 1963.
Pathology- Askerkhanov R.P. Surgery of peripheral veins, Makhachkala, 1973; Vishnevsky A. A. and Shraiber M. I. Military field surgery, M., 1975; Zaretsky V. V. and V y x about in with to and I am A. G. Clinical thermography, M., 1976, bibliogr.; Zorin A. B., Kolesov E. V. and Silin V. A. Instrumental methods for diagnosing heart defects and blood vessels, L., 1972, bibliogr.; And with and to about in Yu. F. and T and-x about N about in Yu. A. Inborn defects of peripheral vessels at children, M., 1974, bibliogr.; Clement A. A. and Vedensky A. N. Surgical treatment of diseases of the veins of the extremities, L., 1976; Knyazev M. D. and B e l about r at with about in O. S. Acute thromboses and embolisms of bifurcation of an aorta and arteries of extremities, Minsk, 1977, bibliogr.; Kornilov V. A. and Kostyuk G. A * Long-term results of treatment of injuries of the main arteries of the extremities, Vestn, hir., t. 116, No. 2, p. 127, 1976; Krakovsky N. I. and Taran about vich V. A. Hemangiomas, M., 1974, bibliogr.; Lytkin M.I. and K o l about m and e c V.P. Acute trauma of the main blood vessels, L., 1973, bibliogr.; Milov anov A. P. Pathomorphology of angiodysplasia of the extremities, M., 1978; The experience of Soviet medicine in the Great Patriotic War of 1941 - 1945, v. 19, p. 26, M., 1955; Petrovsky BV Surgical treatment of vascular wounds, M., 1949, bibliogr.; about N e, Our experience in emergency vascular surgery, Khirurgiya, No. 4, p. 9, 1975; Petrovsky B.V., Belichenko I.A. and Krylov V.S. Surgery of the branches of the aortic arch, M., 1970, bibliogr.; Petrovsky B. V., To N I z e in M. D. and With to at and-n I am M. A. Operations at chronic occlusions of an aortofemoral zone, Khirurgiya, No. 1, p. 12, 1971; Reconstructive surgery, ed. B. V. Petrovsky, p. 107, M., 1971; Guidelines for the pathoanatomical diagnosis of human tumors, ed. N. A. Kraevsky and A. V. Smolyannikov, p. 57, M., 1976, bibliography; Savelyev V. S., D at m-p e E. P. and I b l about to about in E. G. Diseases of the main veins, M., 1972; Lehrbuch der Rontgendiagnostik, hrsg. v. H. R. Schinz u. a., Bd 4, Vol. 1, Stuttgart, 1968; Lou Gibson H. Photography by infrared, N. Y., 1978; L u z s a G. X-ray anatomy of the vascular system, Budapest, 1974; Vascular surgery, ed. by R. B. Rutherford, Philadelphia, 1977.
B. V. Petrovsky, M. D. Knyazev, V. S. Saveliev; I. I. Deryabin, V. A. Kornilov (military), Yu. F. Isakov, Yu. A. Tikhonov (det. hir.), V. V. Kupriyanov (an.), I. G. Olkhovskaya ( onc.), H. E. Yarygin (stalemate. An.).
- the most important physiological mechanism responsible for nourishing body cells and removing harmful substances from the body. The main structural component is the vessels. There are several types of vessels that differ in structure and function. Vascular disease leads to serious consequences negatively affecting the entire body.
General information
A blood vessel is a hollow, tube-shaped formation that permeates body tissues. Blood is transported through the vessels. In humans, the circulatory system is closed, as a result of which the movement of blood in the vessels occurs under high pressure. Transportation through the vessels is carried out due to the work of the heart, which performs a pumping function.
Blood vessels can change under the influence of certain factors. Depending on the external influence, they expand or narrow. The process is regulated by the nervous system. The ability to expand and contract provides a specific structure of human blood vessels.
Vessels are made up of three layers:
- External. The outer surface of the vessel is covered with connective tissue. Its function is to protect against mechanical stress. Also, the task of the outer layer is to separate the vessel from nearby tissues.
- Average. Contains muscle fibers characterized by mobility and elasticity. They provide the ability of the vessel to expand or contract. In addition, the function of the muscle fibers of the middle layer is to maintain the shape of the vessel, due to which there is a full-fledged unhindered blood flow.
- Interior. The layer is represented by flat single-layer cells - endothelium. The tissue makes the vessels smooth inside, thereby reducing the resistance to blood flow.
It should be noted that the walls of venous vessels are much thinner than arteries. This is due to a small amount of muscle fibers. The movement of venous blood occurs under the action of skeletal blood, while arterial blood moves due to the work of the heart.
In general, the blood vessel is the main structural component of cardio-vascular system through which blood moves to tissues and organs.
Types of vessels
Previously, the classification of human blood vessels included only 2 types - arteries and veins. AT this moment There are 5 types of vessels that differ in structure, size, and functional tasks.
Types of blood vessels:
- . Vessels provide the movement of blood from the heart to the tissues. Characterized by thick walls high content muscle fibres. Arteries are constantly narrowing and expanding, depending on the level of pressure, preventing excess blood flow to some organs and deficiency in others.
- Arterioles. Small vessels that are the terminal branches of arteries. Composed primarily of muscle tissue. They are a transitional link between arteries and capillaries.
- capillaries. smallest vessels penetrating organs and tissues. A feature is very thin walls through which blood is able to penetrate outside the vessels. The capillaries supply the cells with oxygen. At the same time, the blood is saturated with carbon dioxide, which is subsequently excreted from the body through the venous pathways.
- Venules. They are small vessels that connect capillaries and veins. They transport oxygen used by cells, residual waste products, and dying blood particles.
- Vienna. They ensure the movement of blood from the organs to the heart. Contain fewer muscle fibers, which is associated with low resistance. Because of this, the veins are less thick and more likely to be damaged.
Thus, several types of vessels are distinguished, the totality of which forms the circulatory system.
Functional groups
Depending on the location, the vessels perform different functions. In accordance with the functional load, the structure of the vessels differs. Currently, there are 6 main functional groups.
The functional groups of vessels include:
- Shock-absorbing. Vessels belonging to this group have the largest number muscle fibres. They are the largest in the human body and are located in close proximity to the heart (aorta, pulmonary artery). These vessels are the most elastic and resilient, which is necessary to smooth out the systolic waves that form during heart contraction. The amount of muscle tissue in the walls of blood vessels decreases depending on the degree of remoteness from the heart.
- Resistive. These include the final, thinnest blood vessels. Due to the smallest lumen, these vessels provide the greatest resistance to blood flow. The resistive vessels contain many muscle fibers that control the lumen. Due to this, the volume of blood entering the body is regulated.
- Capacitive. They perform a reservoir function, keeping large volumes of blood. AT this group includes large venous vessels that can hold up to 1 liter of blood. Capacitive vessels regulate the movement of blood to, controlling its volume in order to reduce the workload on the hearts.
- Sphincters. They are located in the terminal branches of small capillaries. By constriction and expansion, the sphincter vessels control the amount of incoming blood. With the narrowing of the sphincters, the blood does not flow, as a result of which the trophic process is disturbed.
- Exchange. Represented by the terminal branches of capillaries. The exchange of substances takes place in the vessels, providing nutrition to the tissues and removal of harmful substances. Similar functional tasks are performed by venules.
- Shunting. Vessels provide communication between veins and arteries. This does not affect the capillaries. These include atrial, main and organ vessels.
In general, there are several functional groups of vessels that provide a full flow of blood and nutrition of all body cells.
Regulation of vascular activity
The cardiovascular system instantly reacts to external changes or influences negative factors inside the body. For example, when stressful situations occur, heart palpitations are noted. The vessels narrow, due to which it increases, and the muscle tissues are supplied with a large amount of blood. Being at rest, more blood flows to the brain tissues and digestive organs.
The nerve centers located in the cerebral cortex and hypothalamus are responsible for the regulation of the cardiovascular system. The signal arising from the reaction to the stimulus affects the center that controls vascular tone. In the future, through the nerve fibers, the impulse moves to the vascular walls.
In the walls of blood vessels there are receptors that perceive pressure surges or changes in the composition of the blood. Vessels are also able to transmit nerve signals to the appropriate centers, notifying of a possible danger. This makes it possible to adapt to changing environmental conditions, such as changes in temperature.
The work of the heart and blood vessels is affected. This process called humoral regulation. Adrenaline, vasopressin, acetylcholine have the greatest effect on the vessels.
Thus, the activity of the cardiovascular system is regulated by the nerve centers of the brain and endocrine glands responsible for the production of hormones.
Diseases
Like any organ, the vessel can be affected by diseases. The causes of the development of vascular pathologies are often associated with in the wrong way human life. Less often, diseases develop due to congenital abnormalities, acquired infections, or against the background of concomitant pathologies.
Common vascular diseases:
- . It is considered one of the most dangerous pathologies of the cardiovascular system. With this pathology, blood flow through the vessels that feed the myocardium, the heart muscle, is disrupted. Gradually, due to atrophy, the muscle weakens. As a complication are a heart attack, as well as heart failure, in which sudden cardiac arrest is possible.
- Cardiopsychoneurosis. A disease in which the arteries are affected due to malfunctions nerve centers. Spasm develops in the vessels due to excessive sympathetic influence on muscle fibers. Pathology often manifests itself in the vessels of the brain, also affects the arteries located in other organs. The patient has intense pain, interruptions in the work of the heart, dizziness, changes in pressure.
- Atherosclerosis. A disease in which the walls of blood vessels narrow. This leads to a number of negative consequences, including atrophy of the supply tissues, as well as a decrease in the elasticity and strength of the vessels located behind the constriction. is a provoking factor in many cardiovascular diseases, and leads to the formation of blood clots, heart attack, stroke.
- aortic aneurysm. With such a pathology, saccular bulges form on the walls of the aorta. In the future, scar tissue is formed, and the tissues gradually atrophy. As a rule, pathology develops against the background chronic form hypertension, infectious lesions, including syphilis, as well as anomalies in the development of the vessel. If left untreated, the disease provokes rupture of the vessel and death of the patient.
- . Pathology in which the veins of the lower extremities are affected. They expand greatly due to increased load, while the outflow of blood to the heart is greatly slowed down. This leads to swelling and pain. Pathological changes in the affected veins of the legs are irreversible, the disease in the later stages is treated only surgically.
- . A disease in which varicose veins develop in the hemorrhoidal veins that feed lower divisions intestines. Late stages of the disease are accompanied by prolapse of hemorrhoids, heavy bleeding, violation of the chair. Infectious lesions, including blood poisoning, act as a complication.
- Thrombophlebitis. Pathology affects the venous vessels. The danger of the disease is explained by the potential for a blood clot to break off, which blocks the lumen of the pulmonary arteries. However, large veins are rarely affected. Thrombophlebitis affects small veins, the defeat of which does not pose a significant danger to life.
There is a wide range of vascular pathologies that have a negative impact on the functioning of the whole organism.
While watching the video, you will learn about the cardiovascular system.
Blood vessels are an important element of the human body responsible for the movement of blood. There are several types of vessels that differ in structure, functionality, size, location.
Blood vessels are the most important part of the body, which is part of the circulatory system and permeates almost the entire human body. They are absent only in the skin, hair, nails, cartilage and cornea of the eyes. And if they are assembled and stretched into one straight line, then the total length will be about 100 thousand km.
These tubular elastic formations function continuously, transferring blood from the constantly contracting heart to all corners of the human body, saturating them with oxygen and nourishing them, and then returning it back. By the way, the heart pushes more than 150 million liters of blood through the vessels in a lifetime.
The main types of blood vessels are: capillaries, arteries, and veins. Each type performs its specific functions. It is necessary to dwell on each of them in more detail.
Division into types and their characteristics
The classification of blood vessels is different. One of them involves division:
- on arteries and arterioles;
- precapillaries, capillaries, postcapillaries;
- veins and venules;
- arteriovenous anastomoses.
They represent a complex network, differing from each other in structure, size and their specific function, and form two closed systems connected to the heart - circulatory circles.
The following can be distinguished in the device: the walls of both arteries and veins have a three-layer structure:
- an inner layer that provides smoothness, built from the endothelium;
- medium, which is a guarantee of strength, consisting of muscle fibers, elastin and collagen;
- top layer of connective tissue.
Differences in the structure of their walls are only in the width of the middle layer and the predominance of either muscle fibers or elastic ones. And also in the fact that venous - contain valves.
arteries
They deliver blood saturated with useful substances and oxygen from the heart to all cells of the body. By structure, human arterial vessels are more durable than veins. Such a device (more dense and durable middle layer) allows them to withstand the stress of high internal blood pressure.
The names of arteries, as well as veins, depend on:
Once upon a time it was believed that the arteries carry air and therefore the name is translated from Latin as “containing air”.
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There are such types:
Arteries, leaving the heart, become thinner to small arterioles. This is the name of the thin branches of the arteries, passing into the precapillaries, which form the capillaries.
These are the thinnest vessels, with a diameter much thinner than a human hair. This is the longest part of the circulatory system, and their total number in the human body ranges from 100 to 160 billion.
The density of their accumulation is different everywhere, but the highest in the brain and myocardium. They consist only of endothelial cells. They carry out a very important activity: the chemical exchange between the bloodstream and tissues.
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The capillaries are further connected to the post-capillaries, which become venules - small and thin venous vessels that flow into the veins.
Vienna
These are the blood vessels that carry oxygen-depleted blood back to the heart.
The walls of the veins are thinner than the walls of the arteries, because there is no strong pressure. The most developed layer of smooth muscles in middle wall vessels of the legs, because moving up is not an easy job for the blood under the action of gravity.
Venous vessels (all but the superior and inferior vena cava, pulmonary, collar, renal veins and veins of the head) contain special valves that ensure the movement of blood to the heart. The valves block the return flow. Without them, the blood would drain to the feet.
Arteriovenous anastomoses are branches of arteries and veins connected by fistulas.
Separation by functional load
There is another classification that blood vessels undergo. It is based on the difference in the functions they perform.
There are six groups:
There is another very interesting fact relating to this unique system of the human body. In the presence of excess weight in the body, more than 10 km (per 1 kg of fat) of additional blood vessels are created. It all creates a very heavy load to the heart muscle.
Heart disease and overweight, and even worse, obesity, are always very tightly linked. But the good thing is that the human body is also capable of the reverse process - the removal of unnecessary vessels when getting rid of excess fat(precisely from him, and not just from extra pounds).
What role do blood vessels play in human life? In general, they perform a very serious and important work. They are a transport that ensures the delivery of essential substances and oxygen to every cell of the human body. They also remove carbon dioxide and waste from organs and tissues. Their importance cannot be overestimated.
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