Arteries ligaments. Arteries of the brain.

Arteries ligaments. Arteries of the brain.

The content of the body includes its vascular system, which is part of the body as a whole. Therefore, the nature of the intraorgan arterial bed and the architectonics of the intraorgan arteries correspond to the structure, function, and development of the organ in which these vessels branch out (M. G. Prives). This explains that in different organs the arterial bed is constructed differently, and in similar organs it is approximately the same.

Brain arteries also go from the periphery to the center, and:
a) in the cerebral cortex (screen centers) they have the form of straight and short arteries,
b) in the white matter – direct and long, running along the nerve bundles, and c) vascular networks form in the subcortical nuclei (nuclear centers). In the nerve roots and nerves, the arteries run in endoneurium layers in parallel to the bundles of nerve fibers, to which, like in muscles, they are delivered perpendicular branches, forming longitudinal loops extending along the nerve bundles.

Thus, in organs built from a system of fibers (muscles, ligaments, nerves), the arteries are about the same: they enter in several places along the length of the organ and are located along the fibers. For the nutrition of this organ, not only the arteries that enter directly into it, but also the neighboring ones that give blood through the anastomosis are important. All the arteries of a given organ and its surrounding formations constitute the “organ system of vessels”.

Intraosseous arteries.

Intraosseous arteries.

According to the structure, function and development of the long tubular bones, the latter are obtained: the diaphyseal arteries are the main one (a. Nutritia, or rather a. Diaphyseos princeps), enters the middle part of the diaphysis and is divided into r. proximalis and r. distalis, of which the proximal branch supplies blood to the proximal part of the diaphysis, and the distal branch – to the distal one. At the same time, in the long tubular bones, the main diaphyseal arteries enter not strictly in the middle of the bone and not perpendicular to its long axis, but obliquely. Additional (aa. Diaphyseos accessoriae) penetrate the bone at the ends of the diaphysis. Diaphyseal arteries feed the diaphysis from the inside, and the cortical artery receives the cortical arteries from the periosteum. The presence of two systems of the arteries of the diaphysis explains the possibility of a purulent process affecting one layer of the diaphysis while maintaining the other.

In addition to the diaphyseal arteries, the long tubular bone is also supplied by the arteries that are included in the metaphysis (metaphyseal arteries), the epiphyses (epiphyseal arteries), and the apophyses (apophyseal arteries). Epiphyseal cartilage first separates the vessels of the epiphysis from the vessels of the metaphysis; as sostostirovaniya all vessels are interconnected, forming a single system for a given bone. In the short tubular bones with one epiphysis (metacarpus and tarsus), there is one system of epiphyseal arteries. In the short spongy bones (vertebrae, wrist, tarsus, sternum), the vessels enter from different sides, heading towards the points of origin of ossification.

The arteries of the ligaments run along the bundles of connective tissue and along with them are located perpendicular to the corresponding axis of rotation. Muscle arteries go first along the functional axis of the muscle, then penetrate into the perimysium internum and follow it in parallel with the bundles of muscle fibers, giving them perpendicular branches, forming loops stretched along the muscle bundles.

The organs of the lobed structure (lungs, liver, kidneys) of the arteries enter the center of the organ and diverge (three-dimensional) to the periphery of the organ lobes and lobes, respectively.

Patterns of the course of the arteries from the maternal trunk to the organ.

Patterns of the course of the arteries from the maternal trunk to the organ.

With the development of the arterial system, a primary vascular network first appears. In the extreme part of this network, more difficult conditions are created for blood circulation than in those parts that connect the organ and the maternal trunk in the shortest possible way. Therefore, one vessel lying on a straight line between the maternal trunk and the organ is preserved, while the others empty and it turns out that:

1. Arteries travel along the shortest distance, i.e. approximately in a straight line connecting the mother’s trunk with the organ. Therefore, each artery gives branches to nearby organs. This explains that the first branches of the aorta upon its exit from the heart are the arteries to the heart itself. This also explains the order of branching branches, determined by the tab and the location of organs. For example, the branches from the abdominal aorta first go to the stomach (from truncus celiacus), then to the small intestine (a. Mesenterica superior) and, finally, to the large intestine (a. Mesenterica inferior). Or, first, the arteries to the adrenal gland (a. Suprarenalis media), and then to the kidney (a. Renalis). In this case, it is the place of the laying of the organ that matters, and not its final position, which explains that a. testicula-fig does not depart from a. femoralis, and from the aorta, near which the testicle has developed. On the contrary, the scrotum, which originated in the area of ​​the external genital organs, receives the arteries at the site of aa. pudendae externae, originating from the nearest large trunk, a. lemoralis. Knowing the law of the shortest distance and the history of development, one can always determine those organs and those branches to them that depart from a given artery.

2. Arteries are located on the flexion surfaces of the body, because when unbending the vascular tube stretches and collapses. This explains, for example, the location of the common carotid artery on the front surface of the neck, the large arteries of the hand on the palm side. In the lower limb, where the flexion side is located in the hip joint in the front, and in the knee – in the back, the femoral artery passes from the front surface of the thigh to the rear, acquiring a spiral stroke.

3. Arteries are located in sheltered places in the gutters and channels formed by bones, muscles and fascia that protect blood vessels from compression. Since the four-legged open and unprotected is the dorsal side of the body, the vessels are located on the ventral side, which is preserved in humans. This explains the location of the aorta and its branches in front of the spinal column, and the arteries in the neck and extremities – mainly on the front surface. There are no large arteries on the back.

4. Arteries enter the organ on a concave medial or internal surface facing the power source. Therefore, all the gates of the viscera are on a concave surface directed toward the midline, where the aorta lies, sending branches to them.

5. Arteries form adaptations according to the function of the organ:

a) vascular networks, rings, and arcuate anastomoses are observed in organs associated with movement. Thus, in the area of ​​the joints, the articular network, the rete articulare, is formed from the branches of large arteries passing by them, due to which blood flows to the joint, despite the fact that during its movements a part of the vessels is compressed or stretched. Moving entrails that change the size and shape, such as the stomach and intestines, have a large number of annular and arcuate anastomoses;

b) the caliber of the arteries is determined not only by the size of the organ, but also by its function. Thus, the renal artery is not inferior in its diameter to the mesenteric, supplying the long intestine, as it carries blood to the kidney, whose urinary function requires a large flow of blood. Thyroid arteries are also more laryngeal arteries, because a hormone-producing thyroid gland requires more blood than blood supply to the larynx;

c) in connection with this, all endocrine glands receive multiple sources of nutrition. For example, the same thyroid gland – from all nearby large arteries: carotid, subclavian and aorta; adrenal gland – from a. phrenica inferior (a. suprarenalis superior), from the aorta (a. suprarenalis media) and from the renal artery (a. suprarenalis inferior).

Patterns of distribution of arteries

Patterns of distribution of arteries

The arterial system reflects in its structure the general laws of the structure and development of the organism and its individual systems. By supplying blood to various organs, it corresponds to the structure, function, and development of these organs. Therefore, the distribution of arteries in the human body is subject to certain laws, which can be divided into the following groups.

Extraorganic arteries

1. Accordingly, the grouping “… the whole body around the nervous system” arteries are located along the nerve tube and nerves. So, parallel to the spinal cord is the main arterial trunk – the aorta and aa. spinales anterior et posterior. Each segment of the spinal cord corresponds to segmental rr. spinales of the corresponding arteries. In addition, arteries are initially laid in connection with the main nerves: for example, on the upper limb due to n. medianus, on the bottom – with n. ischiadicus. Therefore, in the future, they go along with the nerves, forming neurovascular bundles, which also include veins and lymphatic vessels. There is a relationship between nerves and vessels (“neurovascular connections”), which contributes to the implementation of a single neurohumoral regulation.
2. Accordingly, the division of the body into the organs of plant and animal life of the artery is divided into parietal – to the walls of the body cavities and visceral – to their contents, i.e., to the viscera. Example: parietal and visceral branches of the descending aorta.
3. Each limb receives one main trunk: for the upper limb – a. subclavia, for the bottom – a. ilica externa.
4. The arteries of the trunk maintain a segmental structure: aa. intercostales posteriores, lumbales, rr. spinales and others …
5. Most of the arteries are located on the principle of bilateral symmetry: the paired artery of the soma and the viscera. Departure from this principle is associated with the development of arteries within the primary mesenteries.
6. Arteries go along with other parts of the vascular system – with veins and lymphatic vessels, forming a common vascular complex. The structure of this complex should include thin and long additional arteries and veins parallel to the main and components of the so-called para-arterial and para-venous bed of the vessels.
7. Arteries go according to the skeleton, which forms the basis of the body. So, along the spinal column is the aorta, along the ribs – intercostal arteries. In the proximal parts of the extremities that have one bone (shoulder, hip), there is one main vessel (brachial, femoral artery); in the middle sections, with two bones (forearm, lower leg), there are two main arteries (radial and ulnar, major and minor shin); finally, in the distal regions, the hands and the foot, which have a ray structure, the arteries go according to each finger ray.

Formation of the inferior vena cava

Formation of the inferior vena cava

The formation of the inferior vena cava is associated with the appearance of anastomoses between the posterior cardinal veins. One anastomosis, located in the iliac region, drains blood from the left lower extremity to the right posterior cardinal vein; as a result, the segment of the left posterior cardinal vein, located above the anastomosis, is reduced, and the anastomosis itself is transformed into the left common iliac vein. The right posterior cardinal vein at the site before the confluence of the anastomosis (which has become the left common iliac vein) is converted into the right common iliac vein, and from the site of the junction of both iliac veins to the confluence of the renal veins develops into the secondary inferior vena cava.

The rest of the secondary inferior vena cava is formed from the unpaired primary inferior vena cava flowing into the heart, which connects to the right inferior cardinal vein at the confluence of the renal veins (there is a 2nd anastomosis between the cardinal veins that drains blood from the left kidney). Thus, the finally formed inferior vena cava is composed of 2 parts: from the right posterior cardinal vein (before the confluence of the renal veins) and from the primary inferior vena cava (after its confluence). Since in the inferior vena cava the blood is drained from the entire caudal half of the body into the heart, the value of the posterior cardinal veins weakens, they lag behind in development and turn into v. azygos (right posterior cardinal vein) and in v. hemiazygos and v. hemiazygos accessoria (left posterior cardinal vein). V. hemiazygos falls into v. azygos through the 3rd anastomosis developing in the thoracic region between the former posterior cardinal veins. The portal vein is formed due to the transformation of the yolk veins, through which blood from the yolk sac enters the liver. Vv. omphalomesentericae in the space from the confluence of the mesenteric vein to the gate of the liver into the portal vein.

The development of veins.

The development of veins.

At the beginning of the placental circulation, when the heart is in the cervical region and not yet divided by partitions into the venous and arterial halves, the venous system has a relatively simple device. Large veins pass along the body of the embryo: in the region of the head and neck, the anterior cardinal veins (right and left) and in the rest of the body, the right and left posterior cardinal veins. Approaching the venous sinus of the heart, the anterior and posterior cardinal veins on each side merge to form common cardinal veins (right and left), which, having at first strictly transverse course, flow into the venous sinus of the heart. Along with the paired cardinal veins, there is another unpaired venous trunk – the primary vena cava inferior, which also flows into the venous sinus in the form of a small vessel. Thus, at this stage of development, three venous trunks flow into the heart: paired common cardinal veins and unpaired primary inferior vena cava.

Further changes in the location of the venous trunks are associated with the displacement of the heart from the cervical region downwards and the division of its venous part into the right and left atria. Due to the fact that after the separation of the heart, both common cardinal veins flow into the right atrium, the blood flow in the right common cardinal vein is in more favorable conditions. In this regard, an anastomosis appears between the right and left anterior cardinal veins, through which blood flows from the head into the right common cardinal vein. As a result, the left common cardinal vein ceases to function, its walls collapse and it is obliterated, with the exception of a small part, which becomes the coronary sinus of the heart, sinus coronarius cordis. The anastomosis between the anterior cardinal veins gradually increases, turning into a vena brachiocephalica sinistra, and the left anterior cardinal vein below the anastomosis is obliterated. Two vessels form from the right anterior cardinal vein: a part of the vein above the confluence of the anastomosis turns into a vena brachiocephalica dextra, and a part below it together with the right common cardinal vein is converted into the superior vena cava, collecting blood from the entire cranial half of the body. If an anastomosis is described as underdeveloped, an abnormal development is possible in the form of two superior vena cava.

Ventral aorta

Ventral aorta

Both ventral aorta in the area between the fourth and third aortic arcs are converted into common carotid arteries, aa. carotides communes, and due to the above transformations of the proximal ventral aorta, the right common carotid artery turns out to be extending from the brachiocephalic trunk, and the left one directly from the arcus aortae. In the future, the ventral aorta is transformed into the external carotid artery, aa. carotides externae.

The third pair of aortic arches and the dorsal aorta in the segment from the third to the first branchial arch develop into the internal carotid arteries, aa. carotides internae, bbm, and it is explained that the internal carotid arteries lie more laterally in the adult than the external. The second pair of aortic arches turns into aa. linguales et pharyngeae, and the first pair – in the maxillary, facial and temporal arteries. In violation of the normal course of development, various anomalies arise.

From the dorsal aorta, a series of small paired vessels arises, running in the dorsal direction on both sides of the neural tube. Since these vessels diverge at regular intervals into the loose mesenchymal tissue located between the somites, they are called the dorsal intersegmental arteries. In the neck, on both sides of the body, they are joined early by a series of anastomoses, forming longitudinal vessels – the vertebral arteries.

At the level of the 6th, 7th and 8th cervical intersegmental arteries, the kidneys of the upper extremities are laid. One of the arteries, usually the 7th, grows into the upper limb and increases with the development of the arm, forming the distal subclavian artery (its proximal part develops, as already indicated, on the right of the 4th aortic arch, on the left grows from the left dorsal aorta, which the 7th intersegmental arteries connect).

Subsequently, the cervical intersegmental arteries are obliterated, as a result of which the vertebral arteries are derived from the subclavian.

Thoracic and lumbar intersegmental arteries give rise to aa. intercostales posteriores and aa. lumbales.

The abdominal visceral arteries develop partly from aa. omphalomesentericae (yolk-mesenteric circulation) and part of the aorta.

Arteries of the limbs were originally laid along the nerve trunks in the form of loops.

Some of these loops (along the n. Femoralis) develop into the main arteries of the extremities, others (along the n. Medianus, n. Ischiadicus) remain companions of nerves.

The development of arteries.

The development of arteries.

Reflecting the transition in the process of phylogenesis from the gill circle of the blood circulation to the pulmonary, in a person during ontogenesis, aortic arches are first laid, which are then transformed into the arteries of the pulmonary and bodily circles of the blood circulation. At the 3-week-old embryo truncus arteriosus, leaving the heart, gives rise to two arterial trunks, called the ventral aorta (right and left). The ventral aorta travels upward, then back to the dorsal side of the embryo; here, passing along the sides of the notochord, they are already going in a downward direction and are called dorsal aorta. The dorsal aorta gradually converges with each other and in the middle part of the embryo merge into one unpaired descending aorta. As the embryo of the gill arches develops, the so-called aortic arch, or artery, forms in each of them; these arteries interconnect the ventral and dorsal aorta on each side. Thus, in the area of ​​the gill arches, the ventral (ascending) and dorsal (descending) aortae are interconnected by means of 6 pairs of aortic arches.

In the future, part of the aortic arches and part of the dorsal aorta, especially the right, is reduced, and large primary and main arteries develop from the remaining primary vessels, namely: truncus arteriosus, as noted above, is divided by the frontal septum into the ventral part, from which the pulmonary trunk is formed, and dorsal, turning into ascending aorta. This explains the location of the aorta behind the pulmonary trunk. It should be noted that the latter, due to the current of blood, a pair of aortic arcs, which in lungfish and amphibians gains connection with the lungs, is transformed in humans into two pulmonary arteries – right and left, branches of truncus pulmonalis. At the same time, if the right sixth aortic arch remains only on a small proximal segment, then the left remains all over, forming ductus arteriosus, which connects the pulmonary trunk with the end of the aortic arch, which is important for the circulation of the fetus (see below). The fourth pair of aortic arches remains on both sides all over, but gives rise to different vessels. The left 4th aortic arch together with the left ventral aorta and part of the left dorsal aorta form the aortic arch, arcus aortae.

The proximal segment of the right ventral aorta turns into the brachiocephalic trunk, truncus blachiocephalicus, the right 4th aortic arch – into the beginning of the right subclavian artery extending from the named trunk, a. subclavia dextra. The left subclavian artery grows from the left dorsal aorta caudal to the last aortic arch. Dorsal aorta in the area between the 3rd and 4th aortic arches are obliterated; in addition, the right dorsal aorta is also obliterated from the place of the right subclavian artery to the junction with the left dorsal aorta.

Heart development

Heart development

The heart develops from two symmetric primordia, which then merge into a single tube located in the neck. Due to the rapid growth of the tube in length, it forms an S-shaped loop). The first contractions of the heart begin at a very early stage of development, when the muscle tissue is barely distinguishable. The S-shaped heart loop distinguishes the anterior arterial, or ventricular, part, which continues into the truncus arteriosus, which is divided into two primary aorta, and the posterior venous, or atrial, into which the yolk-mesenteric veins flow, vv. omphalomesentericae.

In this stage, the heart is single-cavity, its division into the right and left halves begins with the formation of the atrial septum. By growing from top to bottom, the septum divides the primary atrium into two – the left and right, and in such a way that subsequently the confluence of the hollow veins are in the right, and the pulmonary veins – in the left.

The septum of the atria has a hole in the middle, foramen ovale, through which the fetal part of the blood from the right atrium enters directly into the left. The ventricle is also divided into two halves by a septum, which grows from the bottom towards the atrial septum, without completing, however, the complete separation of the ventricular cavities.

Sulci, sulci interventriculares appear on the outside according to the boundaries of the ventricular septum. Completion of the septum formation occurs after the truncus arteriosus, in turn, is divided by the frontal septum into two trunks: the aorta and the pulmonary trunk. The partition dividing the truncus arteriosus into two trunks, extending into the ventricular cavity towards the ventricular septum described above and forming the pars membranacea septi interventriculare, completes the separation of the ventricular cavities from each other.

The right atrium is adjacent to the original sinus venosus, which consists of three pairs of veins: the common cardinal vein, or the Cuvier duct (brings blood from the entire body of the embryo), the yolk vein (brings blood from the yolk sac) and the umbilical vein (from the placenta). During the 5th week, the hole leading from the sinus venosus to the atrium expands greatly, so that eventually the wall becomes the wall of the atrium itself. The left process of the sinus, together with the left duct duct that flows here, remains and remains as sinus coronarius cordis.

When flowing into the right atrium, sinus venosus has two venous valves, valvulae venosae dextra et sinistra. The left valve disappears, and valvula venae cavae inferioris and valvula sinus coronarii develop from the right valve. As a developmental abnormality, the 3rd atrium can be obtained, representing either the stretched coronary sinus into which all the pulmonary veins fall, or a separated part of the right atrium.

Microcirculatory bed

Microcirculatory bed

The microcirculatory bed is not a mechanical sum of various vessels, but a complex anatomical and physiological complex consisting of 7 links (5 blood vessels, lymphatic and interstitial) and providing the main vital process of the body – metabolism. Therefore, V. V. Kupriyanov regards it as a microcirculation system.

The structure of the microvasculature has its own characteristics in different organs, corresponding to their structure and function. Thus, in the liver there are wide capillaries – hepatic sinusoids, which receive arterial and venous (from the portal vein) blood. In the kidneys there are arterial capillary glomeruli. Special sinusoids are characteristic of the bone marrow, etc.

Microcirculation fluid is not limited to microscopic blood vessels. The human body is 70% composed of water, which is contained in cells and tissues and makes up the bulk of blood and lymph. Only xls of the whole fluid is in the vessels, and the remaining 4/5 of it is contained in the plasma of cells and in the extracellular medium. Microcirculation of the fluid is carried out, in addition to the circulatory system, also in the tissues, in the serous and other cavities, and in the path of transport of lymph.

From the microvasculature, blood flows through the veins, and lymph through the lymphatic vessels, which ultimately fall into the cardiac veins. Venous blood containing lymph that has joined it, flows into the heart, first into the right atrium, and from it into the right ventricle. From the latter, venous blood enters the lungs through the small (pulmonary) circulation.