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Formation of ATP in the body. ☢ Energy processes in cells: storage and use of energy

The branch of anatomy that studies blood vessels is called angiology. Angiology is the study of the vascular system that transports fluids in closed tubular systems: circulatory and lymphatic.

The circulatory system includes the heart and blood vessels. Blood vessels are divided into arteries, veins, and capillaries. They circulate blood. The lungs are connected to the circulatory system, providing oxygenation of the blood and removing carbon dioxide; the liver, which neutralizes toxic metabolic products contained in the blood and processes some of them; endocrine glands that secrete hormones into the blood; kidneys, which remove non-volatile substances from the blood; and hematopoietic organs, which replenish dead blood elements.

Thus, the circulatory system ensures the metabolism in the body, transports oxygen and nutrients, hormones and mediators to all organs and tissues; removes excretion products: carbon dioxide - through the lungs and aqueous solutions of nitrogenous slags - through the kidneys.

The central organ of the circulatory system is the heart. Knowledge of the anatomy of the heart is very important. Among the causes of death, cardiovascular diseases are in the first place.

The heart is a hollow muscular four-chambered organ. It has two atria and two ventricles. The right atrium and right ventricle are called the right venous heart, containing venous blood. The left atrium and left ventricle are the arterial heart containing arterial blood. Normally, the right half of the heart does not communicate with the left. Between the atria is the atrial septum, and between the ventricles is the interventricular septum. The heart acts as a pump that transports blood throughout the body.

Vessels that go from the heart are called arteries, and those that go to the heart are called veins. The veins flow into the atrium, that is, the atria receive blood. Blood is expelled from the ventricles by the circulation circles.

Development of the heart.

The human heart in ontogenesis repeats phylogenesis. Protozoa and invertebrates (mollusks) have an open circulatory system. In vertebrates, the main evolutionary changes in the heart and blood vessels are associated with the transition from gill-type respiration to pulmonary respiration. The heart of fish is two-chambered, in amphibians it is three-chambered, in reptiles, birds, and mammals it is four-chambered.

The human heart is laid down at the stage of the germinal shield, in the form of paired large vessels and represents two epithelial rudiments that have arisen from the mesenchyme. They form in the region of the cardiogenic plate located under the cranial end of the body of the embryo. In the thickened mesoderm of the splanchnopleura, two longitudinally located endodermal tubes appear on the sides of the head intestine. They bulge into the anlage of the pericardial cavity. As the embryonic shield turns into a cylindrical body, both anlages approach each other and they merge with each other, the wall between them disappears, and a single straight heart tube is formed. This stage is called the simple tubular heart stage. Such a heart is formed by the 22nd day of intrauterine development, when the tube begins to pulsate. In a simple tubular heart, three sections are distinguished, separated by small grooves:

1. The cranial part is called the bulb of the heart and turns into an arterial trunk, which forms two ventral aorta. They curve in an arcuate fashion and continue into the two dorsal descending aorta.

2) The caudal part is called the venous section and continues into

3) Venous sinus.

The next stage is the sigmoid heart. It is formed as a result of uneven growth of the heart tube. At this stage, 4 sections are distinguished in the heart:

venous sinus - where the umbilical and yolk veins flow;

venous department;

arterial department;

arterial trunk.

Stage of a two-chambered heart.

The venous and arterial sections grow strongly, a constriction (deep) appears between them, at the same time from the venous section, which is the common atrium, two outgrowths are formed - the future heart ears, which cover the arterial trunk from both sides. Both knees of the arterial section grow together, the wall separating them disappears and a common ventricle is formed. Both chambers are interconnected by a narrow and short ear duct. In this stage, in addition to the umbilical and yolk veins, two pairs of cardiac veins flow into the venous sinus, that is, a big circle circulation. At the 4th week of embryonic development, a fold appears on the inner surface of the common atrium, growing downwards, a primary interatrial septum is formed.

At 6 weeks, an oval hole forms on this septum. At this stage of development, each atrium communicates with a separate opening with a common ventricle - the stage of a three-chambered heart.

At week 8, a secondary septum grows to the right of the primary interatrial septum, in which there is a secondary foramen ovale. It does not match the original. This allows blood to flow in one direction, from the right atrium to the left. After birth, both septa fuse with each other, and an oval fossa remains in place of the holes. The common ventricular cavity at the 5th week of embryonic development is divided into two halves with the help of a septum growing from below, towards the atria. It does not reach the atrium completely. The final function of the interventricular septum is formed after the arterial trunk is divided by the frontal septum into 2 sections: the pulmonary trunk and the aorta. After that, the continuation of the interatrial septum connects downward with the interventricular septum, and the heart becomes four-chambered.

With a violation of the embryonic development of the heart, the occurrence of congenital heart defects and large vessels is associated. Congenital heart defects account for 1-2% of all defects. According to statistics, they are found from 4 to 8 per 1000 children. In children, congenital heart defects account for 30% of all congenital malformations. The vices are varied. They can be isolated or in various combinations.

There is an anatomical classification of congenital malformations:

anomaly in the location of the heart;

malformations of the anatomical structure of the heart (VSD, VSD)

defects of the main vessels of the heart (open Batal duct, coartation of the aorta);

anomalies of the coronary arteries;

combined vices (triads, pentads).

The heart of a newborn is rounded. The heart grows especially intensively during the first year of life (more in length), the atria grow faster. Up to 6 years, the atria and ventricles grow in the same way, after 10 years, the ventricles increase faster. By the end of the first year, the mass doubles, at 4-5 years old - three times, at 9-10 years old - five times, at 16 years old - 10 times.

The myocardium of the left ventricle grows faster, at the end of the second year it is twice as thick. In children of the first year of life, the heart is located high and transverse, and then an oblique-longitudinal position.

Lecture #5

Anatomy of blood vessels

The existence of blood vessels, such "blood receivers" as arteries and veins, was known even by Aristotle, who gave the name to the largest blood vessel - the aorta.

Attempts to search for regularities in the distribution of blood vessels were made already at the dawn of the development of anatomy. In ancient Chinese anatomical tables, images of canals that permeate the entire body and connect various organs have been preserved. In the medical papyri of ancient Egypt, vessels are mentioned that diverge from the heart to all organs of the body. In ancient Greece, arteries and veins were distinguished, but the main role was assigned to veins. According to the ideas of that time, according to their name, the arteries should contain only air, which was confirmed by the fact that they usually turned out to be bloodless in corpses.

(air- air, terine- save or tereo- I carry). According to ancient scientists, all blood is in the veins.

In the 3rd century BC, Erisostratus conjectured the existence of anastomoses between the small branches of arteries and veins. famous doctor ancient rome Claudius Galen, was convinced that blood is formed in the liver from food gruel coming from the intestines through the portal vein. From the liver, blood is carried by veins throughout the body. In his opinion, "raw blood" enters the right ventricle, then through the opening of the septum into the left ventricle. Here the blood is spiritualized through pneuma and in the form "animal spirit"spiritusanimalis) passes into the arteries to feed the "noble organs". His teaching was canonized by the church.

Later, Avicenna said that the arteries were created to blow through the heart, drive smoky vapor (chad) out of it and, by God's will, distribute pneuma to parts of the body. This view was considered infallible for 15 centuries, until in 1628 the English physician William Harvey introduced the concept of systemic and pulmonary circulation. He wrote “theoretical research and experiments confirmed the following: blood passes through the heart to the lungs, thanks to the contractions of the ventricles, from which it is sent to the whole body, penetrating into the veins and pores of the tissue, and through the veins, first through thin ones, and then through larger ones, returns from the periphery to the center and, finally, through the vena cava passes into the right atrium. Thus, blood flows through the arteries from the center to the periphery, and through the veins from the periphery to the center, in enormous quantities. In animals, the blood is in a circular and constant movement.

Arteries are vessels that carry blood away from the heart. Anatomically, arteries of large, medium and small calibers and arterioles are distinguished. The arterial wall consists of 3 layers:

Internal - intima, consists of endothelium (flat cells) located on the subendothelial plate, in which there is an internal elastic membrane.

Medium - media

The outer layer is adventitia.

Depending on the structure of the middle layer, the arteries are divided into 3 types:

Elastic type arteries (aorta and pulmonary trunk) - the media consists of elastic fibers, which gives these vessels the elasticity necessary for the high pressure that develops when blood is ejected.

Mixed type arteries - the media consists of different quantity elastic fibers and smooth myocytes.

Arteries of the muscular type - the media consists of circularly arranged individual myocytes.

By topography, the arteries are divided into main, organ and intraorgan arteries.

The main arteries - enrich the individual parts of the body with blood.

Organ - enrich individual organs with blood.

Intraorganic - branches inside the organs.

Arteries extending from the main, organ vessels are called branches. There are two types of arterial branching.

main

loose

It depends on the structure of the body. The topography of the arteries is not random, but regular. The laws of arterial topography were formulated by Lesgaft in 1881 under the title "General Laws of Angiology". These were added later:

Arteries are sent to the organs along the shortest path.

The arteries on the limbs run on the flexor surface.

Arteries approach the organs from their inner side, that is, from the side facing the source of blood supply. They enter the organs through the gate.

There is a correspondence between the plan of the structure of the skeleton and the structure of the vessels. In the area of the joints, the arteries form arterial networks.

The number of arteries supplying blood to one organ does not depend on the size of the organ, but on its function.

Within the organs, the division of the arteries corresponds to the plan for the division of the organ. In lobular - interlobar arteries.

Vienna- Vessels that carry blood to the heart. In most veins, blood flows against gravity. The blood flow is slower. The balance of the venous blood of the heart with the arterial one is achieved in general by the fact that the venous bed is wider than the arterial one due to the following factors:

more veins

more caliber

high density of the venous network

formation of venous plexuses and anastomoses.

Venous blood flows to the heart through the superior and inferior vena cava and the coronary sinus. And it flows in one vessel - the pulmonary trunk. In accordance with the division of organs into vegetative and somatic, veins in the cavities are parietal and visceral.

On the extremities, the veins are deep and superficial. The patterns of location of deep veins are the same as arteries. They go in the same bundle along with the arterial trunks, nerves and lymphatic vessels. Superficial veins are accompanied by cutaneous nerves.

The veins of the body walls have a segmental structure

The veins follow the skeleton.

Superficial veins contact saphenous nerves

Veins in internal organs that change their volume form venous plexuses.

Differences between veins and arteries .

in shape - the arteries have a more or less regular cylindrical shape, and the veins either narrow or expand in accordance with the valves located in them, that is, they have a tortuous shape. The arteries are round in diameter, and the veins are flattened due to compression by neighboring organs.

According to the structure of the wall - in the wall of the arteries, the smooth muscles are well developed, there are more elastic fibers, the wall is thicker. Veins are thinner-walled because they have less blood pressure.

There are more veins than arteries. Most arteries of medium caliber are accompanied by two veins of the same name.

The veins form numerous anastomoses and plexuses among themselves, the significance of which is that they fill the space vacated in the body under certain conditions (emptying hollow organs, changing the position of the body)

The total volume of veins is approximately twice that of arteries.

Availability of valves. Most veins have valves, which are a semilunar duplication of the inner lining of the veins (intima). Smooth muscle bundles penetrate into the base of each valve. The valves are arranged in pairs opposite each other, especially where some veins flow into others. The value of the valves is that they prevent the backflow of blood.

There are no valves in the following veins:

Vena cava

portal veins

Shoulder veins

iliac veins

Cerebral veins

Veins of the heart, parenchymal organs, red bone marrow

In the arteries, the blood moves under the pressure of the ejected force of the heart, at the beginning the speed is greater, about 40 m / s, and then slows down.

The movement of blood in the veins is provided the following factors: this is the force of constant pressure, which depends on the push of the blood column from the heart and arteries, etc.

Auxiliary factors include:

the suction force of the heart during diastole - expansion of the atria due to which negative pressure is created in the veins.

suction action of the respiratory movements of the chest on the veins of the chest

muscle contraction, especially in the limbs.

Blood not only flows in the veins, but is also stored in the venous depots of the body. 1/3 of the blood is in the venous depots (spleen up to 200 ml, in the veins of the portal system up to 500 ml), in the walls of the stomach, intestines and in the skin. Blood is expelled from the venous depots as needed - to increase blood flow during increased physical activity or a large amount of blood loss.

Blood vessels

Blood vessels are elastic tubular formations in the body of animals and humans, through which the force of a rhythmically contracting heart or pulsating vessel moves blood through the body: to organs and tissues through arteries, arterioles, arterial capillaries, and from them to the heart - through venous capillaries, venules and veins.

Vessel classification

Among the vessels of the circulatory system, arteries, arterioles, capillaries, venules, veins and arteriolovenous anastomoses are distinguished; vessels of the microcirculatory system carry out the relationship between arteries and veins. Vessels of different types differ not only in their thickness, but also in tissue composition and functional features.

Vessels of the microcirculatory bed include vessels of 4 types:

Arterioles, capillaries, venules, arteriolo-venular anastomoses (AVA)

Arteries are the vessels that carry blood from the heart to the organs. The largest of them is the aorta. It originates from the left ventricle and branches into arteries. The arteries are distributed in accordance with the bilateral symmetry of the body: in each half there is a carotid artery, subclavian, iliac, femoral, etc. Smaller arteries depart from them to individual organs (bones, muscles, joints, internal organs). In the organs, the arteries branch into vessels of even smaller diameter. The smallest of the arteries are called arterioles. The walls of the arteries are quite thick and elastic and consist of three layers:

1) external connective tissue (performs protective and trophic functions),
2) medium, combining complexes of smooth muscle cells with collagen and elastic fibers (the composition of this layer determines the functional properties of the wall of this vessel) and
3) internal, formed by one layer of epithelial cells

According to their functional properties, arteries can be divided into shock-absorbing and resistive. The shock-absorbing vessels include the aorta, pulmonary artery, and areas of large vessels adjacent to them. Elastic elements predominate in their middle shell. Thanks to this device, the rises in blood pressure that occur during regular systoles are smoothed out. Resistive vessels - terminal arteries and arterioles - are characterized by thick smooth muscle walls that can change the size of the lumen when stained, which is the main mechanism for regulating the blood supply to various organs. The walls of the arterioles in front of the capillaries may have local reinforcements of the muscle layer, which turns them into sphincter vessels. They are able to change their inner diameter, up to the complete blocking of the flow of blood through this vessel into the capillary network.

According to the structure of the walls of the artery are divided into 3 types: elastic, muscular-elastic, muscular type.
Elastic type arteries	1. These are the largest arteries - the aorta and the pulmonary trunk. 2. a) Due to the proximity to the heart, pressure drops are especially great here. b) Therefore, high elasticity is required - the ability to stretch during systole of the heart and return to its original state during diastole. c) Accordingly, all membranes contain many elastic elements.
Arteries of the muscular-elastic type	1. This includes large vessels extending from the aorta: -carotid, subclavian, iliac arteries 2. Their middle shell contains approximately equal parts of elastic and muscular elements.
Muscular type arteries	1. These are all other arteries, i.e. arteries of medium and small caliber. 2. a). In their middle shell, smooth myocytes predominate. b). The contraction of these myocytes "supplements" cardiac activity: it maintains blood pressure and gives it additional energy of movement.

Capillaries are the thinnest blood vessels in the human body. Their diameter is 4-20 microns. Skeletal muscles have the densest network of capillaries, where there are more than 2000 of them in 1 mm3 of tissue. The blood flow rate in them is very slow. Capillaries are metabolic vessels in which the exchange of substances and gases between blood and tissue fluid occurs. The capillary walls are composed of a single layer of epithelial cells and stellate cells. Capillaries lack the ability to contract: the size of their lumen depends on the pressure in the resistive vessels.

Moving through the capillaries of the systemic circulation, arterial blood gradually turns into venous blood, which enters the larger vessels that make up the venous system.

In the blood capillaries, instead of three shells, there are three layers,

and in the lymphatic capillary - generally only one layer.

Veins are vessels that carry blood from organs and tissues to the heart. The wall of the veins, like the arteries, is three-layered, but the middle layer is much thinner and contains much less muscle and elastic fibers. The inner layer of the venous wall can form (especially in the veins of the lower body) pocket-like valves that prevent backflow of blood. Veins can hold and eject large quantities blood, thereby contributing to its redistribution in the body. Large and small veins make up the capacitive link of the cardiovascular system. The most capacious are the veins of the liver, abdominal cavity, vascular bed of the skin. The distribution of veins also corresponds to the bilateral symmetry of the body: each side has one large vein. From the lower extremities, venous blood is collected in the femoral veins, which are combined into larger iliac veins, giving rise to the inferior vena cava. Venous blood flows from the head and neck through two pairs of jugular veins, a pair (external and internal) on each side, and from the upper limbs through the subclavian veins. The subclavian and jugular veins eventually form the superior vena cava.

Venules are small blood vessels that provide in a large circle the outflow of oxygen-depleted and saturated blood from the capillaries into the veins.

Blood vessels are elastic elastic tubes through which blood moves. The total length of all human vessels is more than 100 thousand kilometers long, which is enough for 2.5 turns around the earth's equator. During sleep and wakefulness, work and rest - every moment of life, blood moves through the vessels with the force of a rhythmically contracting heart.

Human circulatory system

The circulatory system of the human body divided into lymphatic and circulatory. The main function of the vascular (vascular) system is to deliver blood to all parts of the body. Constant blood circulation is essential for gas exchange in the lungs, protection from harmful bacteria and viruses, and metabolism. Thanks to blood circulation, heat exchange processes are carried out, as well as humoral regulation of internal organs. Large and small vessels connect all parts of the body into a single harmonious mechanism.

Vessels are present in all tissues of the human body with one exception. They do not occur in the transparent tissue of the iris.

Vessels for transporting blood

Blood circulation is carried out through a system of vessels, which are divided into 2 types: human arteries and veins. The layout of which can be represented as two interconnected circles.

arteries- These are rather thick vessels with a three-layer structure. From above they are covered with a fibrous membrane, in the middle there is a layer of muscle tissue, and from the inside they are lined with scales of the epithelium. Through them, oxygenated blood under high pressure is distributed throughout the body. The main and thickest artery in the body is called the aorta. As they move away from the heart, the arteries become thinner and pass into arterioles, which, depending on the need, can contract or be in a relaxed state. Arterial blood is bright red.

Veins are similar in structure to arteries, they also have a three-layer structure, but these vessels have thinner walls and a larger internal lumen. Through them, the blood returns back to the heart, for which the venous vessels are equipped with a system of valves that pass only in one direction. The pressure in the veins is always lower than in the arteries, and the liquid has a dark shade - this is their peculiarity.

Capillaries are a branched network of small vessels covering all corners of the body. The structure of the capillaries is very thin, they are permeable, due to which there is an exchange of substances between the blood and cells.

Device and principle of operation

The vital activity of the body is ensured by the constant coordinated work of all elements of the human circulatory system. The structure and functions of the heart, blood cells, veins and arteries, as well as human capillaries ensure its health and the normal functioning of the whole organism.

Blood refers to fluid connective tissue. It consists of plasma, in which three types of cells move, as well as nutrients and minerals.

With the help of the heart, blood moves through two interconnected circles of blood circulation:

large (corporeal), which carries oxygen-enriched blood throughout the body;
small (pulmonary), it passes through the lungs, which enrich the blood with oxygen.

The heart is the main engine of the circulatory system, which works throughout human life. During the year, this body makes about 36.5 million contractions and passes through itself more than 2 million liters.

The heart is a muscular organ with four chambers:

right atrium and ventricle;
left atrium and ventricle.

The right side of the heart receives less oxygenated blood, which travels through the veins, is pushed out by the right ventricle into the pulmonary artery, and sent to the lungs to be oxygenated. From the capillary system of the lungs, it enters the left atrium and is pushed out by the left ventricle into the aorta and further throughout the body.

Arterial blood fills a system of small capillaries, where it gives oxygen and nutrients to the cells and is saturated with carbon dioxide, after which it becomes venous and goes to the right atrium, from where it is again sent to the lungs. Thus, the anatomy of the network of blood vessels is a closed system.

Atherosclerosis is a dangerous pathology

There are a lot of diseases and pathological changes in the structure of the human circulatory system, for example, narrowing of the lumen of blood vessels. Due to violations of protein-fat metabolism, such a serious disease as atherosclerosis often develops - a narrowing in the form of plaques caused by the deposition of cholesterol on the walls of arterial vessels.

Progressive atherosclerosis can significantly reduce the internal diameter of the arteries up to complete blockage and can lead to coronary heart disease. In severe cases, surgical intervention is inevitable - clogged vessels have to be bypassed. Over the years, the risk of getting sick increases significantly.

An indispensable condition for the existence of the body is the circulation of fluids through the blood vessels that carry blood and the lymphatic vessels through which the lymph moves.

Carries out the transport of liquids and substances dissolved in them (nutrient, waste products of cells, hormones, oxygen, etc.). The cardiovascular system is the most important integrating system of the body. The heart in this system acts as a pump, and the vessels serve as a kind of pipeline through which everything necessary is delivered to every cell of the body.

Blood vessels

Among the blood vessels, larger ones are distinguished - arteries and smaller ones arterioles that carry blood from the heart to the organs venules and veins through which blood returns to the heart, and capillaries, through which blood passes from arterial to venous vessels (Fig. 1). The most important metabolic processes between blood and organs take place in the capillaries, where the blood gives off the oxygen and nutrients contained in it to the surrounding tissues, and takes metabolic products from them. Due to the constant blood circulation, the optimal concentration of substances in the tissues is maintained, which is necessary for the normal functioning of the body.

Blood vessels form a large and small circles of blood circulation, which begin and end in the heart. The volume of blood in a person weighing 70 kg is 5-5.5 liters (approximately 7% of body weight). The blood consists of a liquid part - plasma and cells - erythrocytes, leukocytes and platelets. Due to the high speed of the circulation, 8000-9000 liters of blood flows through the blood vessels daily.

Blood moves at different speeds in different vessels. In the aorta emerging from the left ventricle of the heart, the blood velocity is the highest - 0.5 m / s, in the capillaries - the smallest - about 0.5 mm / s, and in the veins - 0.25 m / s. Differences in the speed of blood flow are due to the unequal width of the total cross section of the bloodstream in different areas. The total lumen of the capillaries is 600-800 times greater than the lumen of the aorta, and the width of the lumen of the venous vessels is approximately 2 times greater than that of the arterial ones. According to the laws of physics, in a system of communicating vessels, the fluid flow rate is higher in narrower places.

The wall of arteries is thicker than that of veins and consists of three sheath layers (Fig. 2). The middle shell is built from bundles of smooth muscle tissue, between which elastic fibers are located. In the inner shell, lined from the side of the lumen of the vessel with endothelium, and on the border between the middle and outer shells, there are elastic membranes. Elastic membranes and fibers form a kind of skeleton of the vessel, giving its walls strength and elasticity.

There are relatively more elastic elements in the wall of the large arteries closest to the heart (the aorta and its branches). This is due to the need to counteract the stretching of the mass of blood that is ejected from the heart during its contraction. As they move away from the heart, the arteries divide into branches and become smaller. In 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, muscle tissue is well developed. Under the influence of nerve stimuli, such arteries are able to change their lumen.

The walls of the veins are thinner, but consist of the same three shells. Since they have much less elastic and muscle tissue, the walls of the veins can collapse. A feature of the veins is the presence in many of them of valves that prevent the reverse flow of blood. Vein valves are pocket-like outgrowths of the inner lining.

Lymphatic vessels

have a relatively thin wall and lymphatic vessels. They also have many valves that allow lymph to move in only one direction - towards the heart.

Lymphatic vessels and flowing through them lymph are also related to the cardiovascular system. Lymphatic vessels, together with veins, provide absorption from the tissues of water with substances dissolved in it: protein molecules, fat droplets, cell decay products, foreign bacteria and others. The smallest lymphatic vessels lymph capillaries- closed at one end and located in the organs next to the blood capillaries. The permeability of the walls of the lymphatic capillaries is higher than that of the blood capillaries, and their diameter is larger, therefore, those substances that, due to their large size, cannot get from the tissues into the blood capillaries, enter the lymphatic capillaries. Lymph in its composition resembles blood plasma; of the cells it contains only leukocytes (lymphocytes).

The lymph formed in the tissues through the lymphatic capillaries, and then through the larger lymphatic vessels, constantly flows into the circulatory system, into the veins of the systemic circulation. During the day, 1200-1500 ml of lymph enters the blood. It is important that before the lymph flowing from the organs enters the circulatory system and mixes with the blood, it passes through the cascade lymph nodes, which are located along the lymphatic vessels. In the lymph nodes, substances foreign to the body and pathogens are retained and neutralized, and the lymph is enriched with lymphocytes.

The location of the vessels

Rice. 3. Venous system
Rice. 3a. Arterial system

The distribution of blood vessels in the human body obeys certain patterns. Arteries and veins usually go together, with small and medium-sized arteries accompanied by two veins. Lymphatic vessels also pass through these vascular bundles. The course of the vessels corresponds general plan structure of the human body (Fig. 3 and 3a). The aorta and large veins run along the spinal column, branches extending from them are located in the intercostal spaces. On the limbs, in those departments where the skeleton consists of one bone (shoulder, thigh), there is one main artery, accompanied by veins. Where there are two bones in the skeleton (forearm, lower leg), there are also two main arteries, and with a radial structure of the skeleton (hand, foot), the arteries are located corresponding to each digital ray. Vessels are directed to organs shortest distance. Vascular bundles pass in hidden places, in channels formed by bones and muscles, and only on the flexion surfaces of the body.

In some places, the arteries are located superficially, and their pulsation can be felt (Fig. 4). So, the pulse can be examined on the radial artery in the lower part of the forearm or on the carotid artery in the lateral region of the neck. In addition, superficial arteries can be pressed against adjacent bone to stop bleeding.

Both the branches of the arteries and the tributaries of the veins are widely interconnected, forming the so-called anastomoses. In case of violations of blood inflow or its outflow through the main vessels, anastomoses contribute to the movement of blood in various directions and its movement from one area to another, which leads to the restoration of blood supply. This is especially important in case of a sharp violation of the patency of the main vessel in atherosclerosis, trauma, injury.

The most numerous and thinnest vessels are blood capillaries. Their diameter is 7-8 microns, and the thickness of the wall formed by one layer of endothelial cells lying on the basement membrane is about 1 micron. The exchange of substances between blood and tissues takes place through the wall of capillaries. Blood capillaries are found in almost all organs and tissues (they are absent only in the outermost layer of the skin - the epidermis, cornea and lens of the eye, hair, nails, tooth enamel). Length of all capillaries human body is approximately 100,000 km. If they are stretched in one line, then you can encircle Earth along the equator 2.5 times. Inside the body, the blood capillaries are interconnected, forming capillary networks. Blood enters the capillary networks of organs through the arterioles, and flows out through the venules.

microcirculation

The movement of blood through the capillaries, arterioles and venules, and lymph through the lymphatic capillaries is called microcirculation, and the smallest vessels themselves (their diameter, as a rule, does not exceed 100 microns) - microvasculature. The structure of the last channel has its own characteristics in different bodies, and the subtle mechanisms of microcirculation allow you to regulate the activity of the organ and adapt it to the specific conditions of the functioning of the body. At every moment it works, that is, it is open and lets blood through, only part of the capillaries, while others remain in reserve (closed). So, at rest, more than 75% of the capillaries of skeletal muscles can be closed. During exercise, most of them open, as a working muscle requires an intensive supply of nutrients and oxygen.

The function of blood distribution in the microvasculature is performed by arterioles, which have a well-developed muscular membrane. This allows them to narrow or expand, changing the amount of blood entering the capillary networks. This feature of the arterioles allowed the Russian physiologist I.M. Sechenov to call them "faucets of the circulatory system."

The study of the microvasculature is possible only with the help of a microscope. That is why an active study of microcirculation and the dependence of its intensity on the state and needs of surrounding tissues became possible only in the 20th century. Capillary researcher August Krogh was awarded in 1920 Nobel Prize. In Russia, a significant contribution to the development of ideas about microcirculation in the 70-90s was made by scientific schools academicians V.V. Kupriyanov and A.M. Chernukha. At present, thanks to modern technical advances, microcirculation research methods (including those using computer and laser technologies) are widely used in clinical practice and experimental work.

Arterial pressure

An important characteristic of the activity of the cardiovascular system is the value of arterial pressure (BP). In connection with the rhythmic work of the heart, it fluctuates, rising during systole (contraction) of the ventricles of the heart and decreasing during diastole (relaxation). The highest blood pressure observed during systole is called the maximum, or systolic. The lowest blood pressure is called the minimum, or diastolic. BP is usually measured in the brachial artery. In healthy adults, the maximum blood pressure is normally 110-120 mm Hg, and the minimum is 70-80 mm Hg. In children, due to the greater elasticity of the arterial wall, blood pressure is lower than in adults. With age, when the elasticity of the vascular walls decreases due to sclerotic changes, the level of blood pressure rises. During muscle work, systolic blood pressure increases, while diastolic blood pressure does not change or decreases. The latter is explained by the expansion of blood vessels in the working muscles. Reducing the maximum blood pressure below 100 mm Hg. called hypotension, and an increase above 130 mm Hg. - hypertension.

The level of blood pressure is maintained by a complex mechanism in which nervous system and various substances carried by the blood itself. So, there are vasoconstrictor and vasodilator nerves, the centers of which are located in the medulla oblongata and spinal cord. There is a significant amount chemical substances, under the influence of which the lumen of blood vessels changes. Some of these substances are formed in the body itself (hormones, mediators, carbon dioxide), others come from the external environment (drugs and food substances). During emotional stress (anger, fear, pain, joy), the hormone adrenaline enters the blood from the adrenal glands. It enhances the activity of the heart and constricts blood vessels, while increasing blood pressure. The thyroid hormone thyroxine works in the same way.

Each person should know that his body has powerful mechanisms of self-regulation, with the help of which the normal state of the vessels and the level of blood pressure are maintained. This provides the necessary blood supply to all tissues and organs. However, it is necessary to pay attention to failures in the activity of these mechanisms and, with the help of specialists, to identify and eliminate their cause.

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The walls of large arteries and small arterioles consist of three layers. outer layer consists of loose connective tissue containing elastic and collagen fibers. The middle layer is represented by smooth muscle fibers that can provide narrowing and expansion of the lumen of the vessel. Internal - formed by a single layer of epithelium (endothelium) and lines the cavity of the vessels.

The diameter of the aorta is 25 mm, arteries - 4 mm, arterioles - 0.03 mm. The speed of blood movement in large arteries is up to 50 cm/s.

The blood pressure in the arterial system is pulsating. Normally, in the human aorta, it is greatest at the time of systole of the heart and is equal to 120 mm Hg. Art., the smallest - at the time of diastole of the heart - 70-80 mm Hg. Art.

Despite the fact that the heart ejects blood into the arteries in portions, the elasticity of the walls of the arteries ensures a continuous flow of blood through the vessels.

The main resistance to blood flow occurs in arterioles due to contraction of the annular muscles and narrowing of the lumen of the vessels. Arterioles are a kind of "faucets" of the cardiovascular system. The expansion of their lumen increases the flow of blood into the capillaries of the corresponding area, improving local blood circulation, and the narrowing sharply impairs blood circulation.

Blood flow in the capillaries

Capillaries are the thinnest (diameter 0.005-0.007 mm) vessels, consisting of a single-layer epithelium. They are located in the intercellular spaces, closely adjacent to the cells of tissues and organs. Such contact with the cells of organs and tissues provides the possibility of a rapid exchange between the blood in the capillaries and the intercellular fluid. This is facilitated by the low speed of blood movement in the capillaries, equal to 0.5-1.0 mm/s. The capillary wall has pores through which water and low molecular weight substances dissolved in it - inorganic salts, glucose, oxygen, etc. - can easily pass from the blood plasma into the tissue fluid at the arterial end of the capillary.

Blood flow in veins

Blood, having passed the capillaries and enriched with carbon dioxide and other metabolic products, enters the venules, which, merging, form larger venous vessels. They carry blood to the heart due to the action of several factors:

pressure difference in the veins and in the right atrium;
contraction of skeletal muscles, leading to rhythmic compression of the veins;
negative pressure in the chest cavity during inspiration, which contributes to the outflow of blood from large veins to the heart;
the presence of valves in the veins that prevent the movement of blood in the opposite direction.

The diameter of the hollow veins is 30 mm, veins - 5 mm, venules - 0.02 mm. The walls of the veins are thin, easily extensible, as they have a poorly developed muscle layer. Under the influence of gravity, the blood in the veins of the lower extremities tends to stagnate, which causes varicose veins. The speed of blood movement through the veins is 20 cm / s or less.

In maintaining a normal outflow of blood from the veins to the heart, muscle activity plays an important role.

The structure of the vascular wall: endothelium, muscle and connective tissue

Vascular wall consists of three main structural components: endothelium, muscle and connective tissue, including elastic elements.

On the content and arrangement of these fabrics in the system of blood vessels, mechanical factors, primarily represented by blood pressure, as well as metabolic factors, which reflect the local needs of tissues, influence. All these fabrics different ratios are present in the vascular wall, with the exception of the wall of capillaries and postcapillary venules, in which the only available building blocks are the endothelium, its basal lamina and pericytes.

Vascular endothelium

Endothelium represents special type epithelium that forms a semi-permeable barrier between two compartments internal environment- blood plasma and interstitial fluid. The endothelium is a highly differentiated tissue capable of actively mediating and controlling extensive bilateral exchange of small molecules and limiting the transport of some macromolecules.

In addition to their roles in the exchange between the blood and surrounding tissues, endothelial cells perform a number of other functions.
1. The transformation of angiotensin I (Greek angeion- vessel + tendere - strain) into angiotensin II.
2. The transformation of bradykinin, serotonin, prostaglandins, norepinephrine, thrombin, and other substances into biologically inert compounds.
3. Lipolysis of lipoproteins by enzymes located on the surface of endothelial cells, with the formation of triglycerides and cholesterol (substrates for the synthesis of steroid hormones and membrane structures).

Angiology is the study of blood vessels.

Muscular artery (left) stained with hematoxylin and eosin and elastic artery (right) stained with Weigert (figures). The media of the muscular artery contains predominantly smooth muscle tissue, while the media of the elastic artery is formed by layers of smooth muscle cells alternating with elastic membranes. In the adventitia and the outer part of the middle shell there are small blood vessels (vasa vasorum), as well as elastic and collagen fibers.

4. Production of vasoactive factors affecting vascular tone, such as endothelins, vasoconstrictors and nitric oxide - a relaxation factor.
Factors growth, such as vascular endothelial growth factors (VEGF), play a leading role in the formation of the vascular system during embryonic development, in the regulation of capillary growth in normal and pathological conditions in adults, and in maintaining the normal state of the vascular bed.

It should be noted that endothelial cells are functionally different depending on the vessel they line.

The endothelium also has antithrombogenic properties and prevents blood clotting. When endothelial cells are damaged, for example, in vessels affected by atherosclerosis, subendothelial connective tissue not covered by endothelium induces aggregation of blood platelets. This aggregation triggers a cascade of phenomena, as a result of which fibrin is formed from blood fibrinogen. This forms an intravascular blood clot, or thrombus, which can grow until a complete disruption of local blood flow occurs.

Dense pieces can be separated from such a thrombus - emboli, - which are carried away with the blood stream and can disrupt the patency of far located blood vessels. In both cases, blood flow can stop, resulting in a potential threat to life. Thus, the integrity of the endothelial layer, which prevents contact between platelets and subendothelial connective tissue, is the most important antithrombogenic mechanism.

Vascular smooth muscle tissue

smooth muscle tissue present in all vessels except capillaries and pericytic venules. Smooth muscle cells are numerous and arranged in helical layers in the media of blood vessels. Each muscle cell is surrounded by a basal lamina and a variable amount of connective tissue; both components are formed by the cell itself. Vascular smooth muscle cells, mainly in arterioles and small arteries, are often interconnected by communicative (gap) junctions.

Vascular connective tissue

Connective tissue is present in the walls of blood vessels, and the number and proportions of its components vary significantly depending on local functional needs. Collagen fibers, an element ubiquitous in the wall of the vascular system, are found between the muscle cells of the middle membrane, in the adventitia, and also in some subendothelial layers. Types IV, III, and I collagens are present in the basement membranes, tunica media, and adventitia, respectively.

Elastic fibers provide elasticity during compression and stretching of the vascular wall. These fibers predominate in large arteries, where they are collected in parallel membranes that are evenly distributed between muscle cells throughout the media. The main substance forms a heterogeneous gel in the intercellular spaces of the vascular wall. It makes a certain contribution to the physical properties of vessel walls and probably affects their permeability and the diffusion of substances through them. The concentration of glycosaminoglycans is higher in arterial wall tissue than in veins.

During aging, the intercellular substance undergoes disorganization due to increased production of collagen types I and III and some glycosaminoglycans. There are also changes in the molecular conformation of elastin and other glycoproteins, as a result of which lipoproteins and calcium ions are deposited in the tissue, followed by calcification. Changes in the components of the intercellular substance, associated with other more complex factors, can lead to the formation of an atherosclerotic plaque.

Skeletal muscle innervation. Mechanisms
Muscle spindles and Golgi tendon organs. Histology
Cardiac muscle: structure, histology
Smooth muscle tissue: structure, histology
Regeneration of muscle tissue. Muscle healing mechanisms
The structure of the cardiovascular system. Vessels of the microvasculature
The structure of the vascular wall: endothelium, muscle and connective tissue
Sheaths of blood vessels: intima, middle sheath, adventitia
Innervation of blood vessels
Elastic arteries: structure, histology

Human cardiovascular system

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Types of blood vessels

All blood vessels in the human body are divided into two categories: vessels through which blood flows from the heart to organs and tissues ( arteries), and vessels through which blood returns from organs and tissues to the heart ( veins). The largest blood vessel in the human body is the aorta, which emerges from the left ventricle of the heart muscle. This is not surprising, since this is the “main pipe” through which the blood flow is pumped, supplying the entire body with oxygen and nutrients. The largest veins, which "collect" all the blood from organs and tissues before sending it back to the heart, form the superior and inferior vena cava, which enter the right atrium.

Between the veins and arteries are smaller blood vessels: arterioles, precapillaries, capillaries, postcapillaries, venules. Actually, the exchange of substances between blood and tissues occurs in the so-called zone of the microcirculatory bed, which is formed by the small blood vessels listed earlier. As mentioned earlier, the transfer of substances from the blood to the tissues and vice versa occurs due to the fact that the walls of the capillaries have micro-holes through which the exchange takes place.

The farther from the heart, and closer to any organ, large blood vessels are divided into smaller ones: large arteries are divided into medium ones, which, in turn, into small ones. This division can be compared to the trunk of a tree. At the same time, the arterial walls have complex structure, they have several shells that provide the elasticity of the vessels and the continuous movement of blood through them. From the inside, the arteries resemble rifled firearms - they are lined from the inside with spiral muscle fibers that form a swirling blood flow, allowing the walls of the arteries to withstand the blood pressure created by the heart muscle at the time of systole.

All arteries are classified into muscular(arteries of the limbs), elastic(aorta), mixed(carotid arteries). The greater the need for a particular organ in the blood supply, the larger the artery approaches it. The most “gluttonous” organs in the human body are the brain (consuming the most oxygen) and the kidneys (pumping large volumes of blood).

As mentioned above, large arteries are divided into medium ones, which are divided into small ones, etc., until the blood enters the smallest blood vessels - capillaries, where, in fact, exchange processes take place - oxygen is given to tissues that are given into the blood carbon dioxide, after which the capillaries gradually gather into veins, which deliver oxygen-poor blood to the heart.

Veins have a fundamentally different structure, unlike arteries, which, in general, is logical, since veins perform a completely different function. The walls of the veins are more fragile, the number of muscle and elastic fibers in them is much less, they are devoid of elasticity, but they stretch much better. The only exception is the portal vein, which has its own muscular membrane, which led to its second name - the arterial vein. The speed and pressure of blood flow in veins is much lower than in arteries.

Unlike arteries, the variety of veins in the human body is much higher: the main veins are called main; veins extending from the brain - villous; from the stomach - plexus; from the adrenal gland - throttle; from the intestines - arcade, etc. All veins, except for the main ones, form plexuses that envelop "their" organ from the outside or inside, thereby creating the most effective opportunities for blood redistribution.

Another distinguishing feature of the structure of veins from arteries is the presence in some veins of internal valves which allow blood to flow in only one direction - towards the heart. Also, if the movement of blood through the arteries is provided only by contraction of the heart muscle, then the movement of venous blood is provided as a result of the suction action of the chest, contractions of the femoral muscles, muscles of the lower leg and heart.

Most a large number of valves are located in the veins of the lower extremities, which are divided into superficial (large and small saphenous veins) and deep (paired veins that unite arteries and nerve trunks). Between themselves, the superficial and deep veins interact with the help of communicating veins, which have valves that ensure the movement of blood from the superficial veins to the deep ones. It is the failure of the communicating veins, in the vast majority of cases, that is the cause of the development of varicose veins.

The great saphenous vein is the longest vein in the human body - its internal diameter reaches 5 mm, with 6-10 pairs of valves. The blood flow from the surfaces of the legs passes through the small saphenous vein.

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ANATOMY OF THE VASCULAR SYSTEM.

The branch of anatomy that studies blood vessels is called angiology. Angiology is the study of the vascular system that transports fluids in closed tubular systems: circulatory and lymphatic.

The circulatory system includes the heart and blood vessels. Blood vessels are divided into arteries, veins, and capillaries. They circulate blood. The lungs are connected to the circulatory system, providing oxygenation of the blood and removing carbon dioxide; the liver neutralizes toxic metabolic products contained in the blood and the processing of some of them; endocrine glands that secrete hormones into the blood; kidneys, which remove non-volatile substances from the blood; and hematopoietic organs, which replenish dead blood elements.

The central organ of the circulatory system is the heart. Knowledge of the anatomy of the heart is very important. Among the causes of death, cardiovascular diseases are in the first place.

Development of the heart.

The human heart is laid down at the stage of the germinal shield, in the form of paired large vessels and represents two epithelial rudiments that have arisen from the mesenchyme. They form in the region of the cardiogenic plate located under the cranial end of the body of the embryo. In the thickened mesoderm of the splanchnopleura, two longitudinally located endodermal tubes appear on the sides of the head intestine. They bulge into the anlage of the pericardial cavity. As the embryonic shield turns into a cylindrical body, both anlages approach each other and they merge with each other, the wall between them disappears, a single straight heart tube is formed. This stage is called the simple tubular heart stage. Such a heart is formed by the 22nd day of intrauterine development, when the tube begins to pulsate. In a simple tubular heart, three sections are distinguished, separated by small grooves:

2) The caudal part is called the venous section and continues into

3) Venous sinus.

The next stage is the sigmoid heart. It is formed as a result of uneven growth of the heart tube. At this stage, 4 sections are distinguished in the heart:

1) venous sinus - where the umbilical and yolk veins flow;

2) venous department;

3) arterial department;

4) arterial trunk.

Stage of a two-chambered heart.

The venous and arterial sections grow strongly, a constriction (deep) appears between them, at the same time from the venous section, which is the common atrium, two outgrowths are formed - the future heart ears, which cover the arterial trunk from both sides. Both knees of the arterial section grow together, the wall separating them disappears and a common ventricle is formed. Both chambers are interconnected by a narrow and short ear duct. In this stage, in addition to the umbilical and yolk veins, two pairs of cardiac veins flow into the venous sinus, that is, a large circle of blood circulation is formed. At the 4th week of embryonic development, a fold appears on the inner surface of the common atrium, growing downward and the primary interatrial septum is formed.

At 6 weeks, an oval hole forms on this septum. At this stage of development, each atrium communicates with a separate opening with a common ventricle - the stage of a three-chambered heart.

At week 8, a secondary septum grows to the right of the primary interatrial septum, in which there is a secondary foramen ovale. It does not match the original. This allows blood to flow in one direction, from the right atrium to the left. After birth, both septa fuse with each other and an oval fossa remains in place of the holes. The common ventricular cavity at the 5th week of embryonic development is divided into two halves with the help of a septum growing from below, towards the atria. It does not reach the atrium completely. The final function of the interventricular septum occurs after the arterial trunk is divided by the frontal septum into 2 sections: the pulmonary trunk and the aorta. After that, the continuation of the interatrial septum connects downward with the interventricular septum and the heart becomes four-chambered.

With a violation of the embryonic development of the heart, the occurrence of congenital heart defects and large vessels is associated. Congenital malformations account for 1-2% of all malformations. According to statistics, they are found from 4 to 8 per 1000 children. In children, congenital malformations account for 30% of all congenital malformations. The vices are varied. They can be isolated or in various combinations.

There is an anatomical classification of congenital malformations:

1) anomaly in the location of the heart;

2) malformations of the anatomical structure of the heart (VSD, VSD)

3) defects of the main vessels of the heart (open Batal duct, coartation of the aorta);

4) anomalies of the coronary arteries;

5) combined defects (triads, pentads).

Aristotle knew about the existence of vessels of such “blood receivers” as atreria and veins. According to the ideas of this time. according to their name, the arteries were supposed to contain only air, which was confirmed by the fact that the arteries in corpses were usually bloodless.

Arteries are vessels that carry blood away from the heart. Anatomically, arteries of large, medium and small calibers and arterioles are distinguished. The arterial wall consists of 3 layers:

1) Internal - intima, consists of endothelium (flat cells) located on the subendothelial plate, in which there is an internal elastic membrane.

2) Medium - media

3) The outer layer is adventitia.

Depending on the structure of the middle layer, the arteries are divided into 3 types:

The elastic type arteries (aorta and pulmonary trunk) media are composed of elastic fibers, which gives these vessels the elasticity necessary for the high pressure that develops when blood is ejected.

2. Arteries of mixed type - the media consists of a different number of elastic fibers and smooth myocytes.

3. Arteries of the muscular type - the media consists of circularly arranged individual myocytes.

By topography, the arteries are divided into main, organ and intraorgan arteries.

The main arteries - enrich the individual parts of the body with blood.

Organ - enrich individual organs with blood.

Intraorganic - branches inside the organs.

Arteries extending from the main, organ vessels are called branches. There are two types of arterial branching.

1) trunk

2) loose

1. Arteries are sent to the organs along the shortest path.

2. Arteries on the limbs go on the flexor surface.

3. Arteries approach the organs from their inner side, that is, from the side facing the source of blood supply. They enter the organs through the gate.

4. There is a correspondence between the plan of the structure of the skeleton and the structure of the vessels. In the area of the joints, the arteries form arterial networks.

5. The number of arteries supplying blood to one organ does not depend on the size of the organ, but on its function.

6. Inside the organs, the division of the arteries corresponds to the plan for the division of the organ. In lobular - interlobar arteries.

Vienna- Vessels that carry blood to the heart. In most veins, blood flows against gravity. The blood flow is slower.

The human circulatory system

The balance of the venous blood of the heart with the arterial one is achieved in general by the fact that the venous bed is wider than the arterial one due to the following factors:

1) more veins

2) more caliber

3) high density of the venous network

4) the formation of venous plexuses and anastomoses.

The veins of the body walls have a segmental structure

The veins follow the skeleton.

Superficial veins contact saphenous nerves

Veins in internal organs that change their volume form venous plexuses.

Differences between veins and arteries.

1) in shape - the arteries have a more or less regular cylindrical shape, and the veins either narrow or expand in accordance with the valves located in them, that is, they have a tortuous shape. The arteries are round in diameter, and the veins are flattened due to compression by neighboring organs.

2) According to the structure of the wall - in the wall of the arteries, the smooth muscles are well developed, there are more elastic fibers, the wall is thicker. Veins are thinner-walled because they have less blood pressure.

3) By number - there are more veins than arteries. Most arteries of medium caliber are accompanied by two veins of the same name.

4) The veins form numerous anastomoses and plexuses among themselves, the significance of which is that they fill the space vacated in the body under certain conditions (emptying hollow organs, changing the position of the body)

5) The total volume of veins is approximately twice as large as that of arteries.

6) Availability of valves. Most veins have valves, which are a semilunar duplication of the inner lining of the veins (intima). Smooth muscle bundles penetrate into the base of each valve. The valves are arranged in pairs opposite each other, especially where some veins flow into others. The value of the valves is that they prevent the backflow of blood.

There are no valves in the following veins:

Vena cava

Portal veins

brachiocephalic veins

The iliac veins

The veins of the brain

Veins of the heart, parenchymal organs, red bone marrow

In the arteries, the blood moves under the pressure of the ejected force of the heart, at the beginning the speed is greater, about 40 m / s, and then slows down.

The movement of blood in the veins is provided by the following factors: this is the force of constant pressure, which depends on the push of the blood column from the heart and arteries, etc.

Auxiliary factors include:

1) the suction force of the heart during diastole - expansion of the atria due to which negative pressure is created in the veins.

2) the suction effect of the respiratory movements of the chest on the veins of the chest

3) muscle contraction, especially on the limbs.

The structure of capillaries.

Their total number is about 40 billion. The total area is about 11 thousand cm 2. capillaries have a wall, represented only by the endothelium. The number of capillaries is not the same in different parts of the body. Not all capillaries are equally in working order, some of them are closed and will be filled with blood as needed. The sizes and diameter of capillaries are from 3-7 microns and more. The narrowest capillaries are in the muscles, and the widest ones are in the skin and mucous membranes of the internal organs (in the organs of the immune and circulatory systems). The widest capillaries are called sinusoids.

Types of blood vessels, features of their structure and function.

Rice. 1. Human blood vessels (front view):
1 - dorsal artery of the foot; 2 - anterior tibial artery (with accompanying veins); 3 - femoral artery; 4 - femoral vein; 5 - superficial palmar arch; 6 - right external iliac artery and right external iliac vein; 7-right internal iliac artery and right internal iliac vein; 8 - anterior interosseous artery; 9 - radial artery (with accompanying veins); 10 - ulnar artery (with accompanying veins); 11 - inferior vena cava; 12 - superior mesenteric vein; 13 - right renal artery and right renal vein; 14 - portal vein; 15 and 16 - saphenous veins of the forearm; 17- brachial artery (with accompanying veins); 18 - superior mesenteric artery; 19 - right pulmonary veins; 20 - right axillary artery and right axillary vein; 21 - right pulmonary artery; 22 - superior vena cava; 23 - right brachiocephalic vein; 24 - right subclavian vein and right subclavian artery; 25 - right common carotid artery; 26 - right internal jugular vein; 27 - external carotid artery; 28 - internal carotid artery; 29 - brachiocephalic trunk; 30 - external jugular vein; 31 - left common carotid artery; 32 - left internal jugular vein; 33 - left brachiocephalic vein; 34 - left subclavian artery; 35 - aortic arch; 36 - left pulmonary artery; 37 - pulmonary trunk; 38 - left pulmonary veins; 39 - ascending aorta; 40 - hepatic veins; 41 - splenic artery and vein; 42 - celiac trunk; 43 - left renal artery and left renal vein; 44 - inferior mesenteric vein; 45 - right and left testicular arteries (with accompanying veins); 46 - inferior mesenteric artery; 47 - median vein of the forearm; 48 - abdominal aorta; 49 - left common iliac artery; 50 - left common iliac vein; 51 - left internal iliac artery and left internal iliac vein; 52 - left external iliac artery and left external iliac vein; 53 - left femoral artery and left femoral vein; 54 - venous palmar network; 55 - a large saphenous (hidden) vein; 56 - small saphenous (hidden) vein; 57 - venous network of the rear of the foot.

Rice. 2. Human blood vessels (back view):
1 - venous network of the rear of the foot; 2 - small saphenous (hidden) vein; 3 - femoral-popliteal vein; 4-6 - venous network of the rear of the Hand; 7 and 8 - saphenous veins of the forearm; 9 - posterior ear artery; 10 - occipital artery; 11- superficial cervical artery; 12 - transverse artery of the neck; 13 - suprascapular artery; 14 - posterior circumflex artery; 15 - artery, enveloping the scapula; 16 - deep artery of the shoulder (with accompanying veins); 17 - posterior intercostal arteries; 18 - superior gluteal artery; 19 - lower gluteal artery; 20 - posterior interosseous artery; 21 - radial artery; 22 - dorsal carpal branch; 23 - perforating arteries; 24 - external upper artery of the knee joint; 25 - popliteal artery; 26-popliteal vein; 27-external lower artery of the knee joint; 28 - posterior tibial artery (with accompanying veins); 29 - peroneal, artery.

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Development of the heart.

Blood vessels

Vessel classification

Human circulatory system

Vessels for transporting blood

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Blood vessels

Lymphatic vessels

The location of the vessels

microcirculation

Arterial pressure

Blood flow in the capillaries

Blood flow in veins

The structure of the vascular wall: endothelium, muscle and connective tissue

Vascular endothelium

Angiology is the study of blood vessels.

Vascular smooth muscle tissue

Vascular connective tissue

Human cardiovascular system

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Types of blood vessels

ANATOMY OF THE VASCULAR SYSTEM.

The human circulatory system

Types of blood vessels, features of their structure and function.

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