Blood vessels elastic tubular education of different diameters that comprise a closed cardiovascular system (Fig. 1 and 2) and perform the function of conveying blood to all organs and tissues, regulates their circulation and participating in metabolism and the gas exchange.
Blood vessels are divided into arteries, veins and capillaries. Artery (see) carry the blood from the heart to all the tissues and organs, forming blood system; Vienna (see) take blood from the organs and tissues to the heart, forming venous system. Capillaries are the most thin the blood vessels connecting tissues end of branching arteries (arterioles) with the beginning of the veins (venules); they close on the periphery blood stream. Capillary walls are deprived of the muscle layer and consist of one layer of flat cells. Due to this structure of the walls of oxygen and carbon dioxide, as well as products of metabolism easily pass from the blood into tissue and in the tissues into the blood. In certain organs of the capillaries are the arteries, for example in the glomeruli of the kidney, or between two veins, for example in the lobules of the liver, and are called "wonderful" networks. Except relations of the arterial and venous systems through capillary, there is a direct link to the smallest arteries and veins through arterio-venous anastomoses, when blood passes, bypassing the capillary channel.
In some anatomical formations (for example, in the cornea, lens, hyaline cartilage, epithelial tissue) blood vessels are not available.
There are two closed system blood vessels (see the blood Circulation). The vessels of large circulation include the aorta (see) and the radiating arteries, upper and lower hollow vein, portal vein with forming their branches;
To the system of lesser circulation belongs pulmonary trunk with its branches - the right and left pulmonary arteries and the same name veins.
Along with blood vessels in the human body there are lymphatic vessels involved lymph from tissues in venous bed. There are lymphatic capillaries, small lymphatic vessels inside the organs, lymphatic vessels on the surface of bodies, draining lymph from the organs, lymphatic shafts and ducts - breast and the right lymphatic duct, which flows into the upper branches Vena cava (see Lymphatic system).
Blood vessels are expressed age peculiarities. Morphological changes are closely linked with the growth of the body, with the structurally-functional change of organs and tissues at different age levels. Age-related changes relate to the diameter of the blood vessels, wall thickness, the macro-microscopic and histological their structure.
Women subcutaneous veins have thinner walls, lesser caliber less clearly speak at the elevation of the skin.
The circulation of the blood vessels is due to its own vessels. In some cases it is carried out by the branches of a nearby arteries. The lining of blood vessels is not. Of the capillary bed in the artery walls formed a vein, usually in the number two accompanying arterial branch. In the walls of the large blood vessels are the lymphatic capillaries and vessels.
Innervation of the blood vessels is vegetative and sensitive somatic nerve fibers, which are suitable to blood vessels in the structure of branches of mixed nerves. The impulses, coming from Innervate the vessels, nerves, or cause expansion or narrowing of the lumen of the vessel. Autonomic nerve fibers, ending motor endings in the cells smooth muscles of blood vessels that carry vasomotor innervation - is the reduction of smooth muscles of blood vessels and the gleam of their tapering. Sensitive nerve fibers in all layers of the wall have a variety of sensitive end - receptors. The presence in the blood vessel walls vasomotor and sensitive nerve fibers provides a reflex reaction vessels in response to various stimuli, from domestic and external environment. In some large blood vessels there are areas with high sensitivity, the so-called reflex zones (area carotid sinus, lung and mouth hollow vein, portal vein, and others).
Congenital arteriovenous aneurysm (see Aneurysm) result from violations of the development of parts of a capillary plexus and vessels of the embryo (malformation). As a consequence, formation of arteriovenous fistula (single large or multiple - small), through which the arterial blood gets in Vienna, bypassing the capillaries, which leads to serious changes of blood circulation. Artery in the field of fistula expands, becomes convoluted, its walls are thin - "venezzia" of the arteries. Venous wall, on the contrary, thickens, expand its muscle and elastic fibers - the so-called arterialization of the veins.
Congenital arteriovenous aneurysm can be localized (the finger) and common throughout the limbs, to meet in all areas and organs of the body; defeat is usually unilateral. For them is characterized by recurrent bleeding, sometimes fatal. Common symptoms of disorders of cardiac activity, unpleasant feelings in the heart, palpitation, shortness of breath, increased heart size, edema, congestive the liver. All these changes come as the result of what the heart has to distill an excessively large amount of blood, as part of blood arrives in the venous system, bypassing the capillaries, through the arteriovenous fistula. Local symptoms are varicose veins, voltage and their ripple, no spadenia veins when lifting legs up. Auscultation of the aneurysm is determined by continuous systolediastole2 noise. It is also noted a significant increase in the limbs, increased skin temperature by 2-3° on the side of destruction, disruption of trophic in the form of hyperhidrosis, ulceration and necrosis, discoloration of the skin with stains of red-purple or brown color. Treatment of congenital arteriovenous aneurysm only surgical ligation fistula and fistula, which connects the artery and vein. When multiple souljah excised all advanced vessels with arterio-venous anastomoses. Surgical treatment of the subject and other vascular anomalies - the double arch of the aorta coarctation of the aorta (narrowing of the isthmus), cleft blood (botallowa) flow and other
With traumatic lesions of the soft tissues, wounds, traumatic amputations of limbs arise primary and secondary bleeding (see Bleeding), pulsating and traumatic hematoma aneurysm. Terrible manifestations injury vessels - bleeding, embolism (see), anemia of the brain, gangrene (see) and others - require emergency active measures: 1) prior to stop the bleeding; 2) the operation of the vessel; 3) prevention of the consequences of blood loss; 4) prevention and treatment of shock (see); 5) prevention and treatment of local ischemic events associated with the trauma of vessels; 6) prevention and treatment of wound infections (see the Wound, injury); 7) the functional treatment of trauma blood vessels, nerves, bones, soft tissues. Consistent and systematic implementation of these measures is particularly needed when the wounds of the blood vessels. The imposition of vascular suture (see) is possible only under appropriate conditions (risk of infection and bleeding). Prolonged compression of blood vessels into the tissues come deep irreversible changes.
With operations in great vessels, accompanied by prolonged cessation of blood flow, the necessity of prevention of ischemic complications.
Among all the methods of prevention of ischaemic complications in these interventions is the most common method bypass blood vessels. The principle bypass surgery is to create a workaround around off from the circulation section of the vessel. For this purpose use of rubber, plastic or metal cannula.