Home Oral cavity Which arteries supply blood to the brain. Anatomy of the blood vessels of the head and neck

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Which arteries supply blood to the brain. Anatomy of the blood vessels of the head and neck

The blood supply to the brain is a separate functional system blood vessels, through which the receipt is carried out nutrients to the cells of the central nervous system and removal of the products of their metabolism. Due to the fact that neurons are extremely sensitive to a lack of microelements, even a minor disruption in the organization of this process negatively affects a person’s well-being and health.

Today, acute violation cerebral blood supply or stroke is the most common cause of human death, the origins of which are in damage to the blood vessels of the brain. The cause of the pathology can be clots, blood clots, aneurysms, looping, and kinks in blood vessels, so it is extremely important to conduct a timely examination and begin treatment.

As you know, for the brain to work and all its cells to function correctly, a continuous supply of a certain amount of oxygen and nutrients to its structures is required, regardless of physiological state person (sleep - wakefulness). Scientists have calculated that the needs of the central nervous system consume about 20% of the oxygen consumed, while its mass in relation to the rest of the body is only 2%.

The brain is nourished through the blood supply to the organs of the head and neck through the arteries that form the arteries of the circle of Willis on the brain and penetrate through it. Structurally, this organ has the most extensive network of arterioles in the body - its length in 1 mm3 of the cerebral cortex is approximately 100 cm, in a similar volume of white matter about 22 cm.

The largest amount is located in the gray matter of the hypothalamus. And this is not surprising, because he is responsible for maintaining consistency internal environment the body through coordinated reactions, or in other words, is the internal “steering wheel” of all vital systems.

Internal structure of the blood supply arterial vessels in the white and gray matter of the brain is also different. For example, the arterioles of the gray matter have thinner walls and are elongated compared to similar structures of the white matter. This allows for the most efficient gas exchange between blood components and brain cells; for this reason, insufficient blood supply primarily affects its performance.

Anatomically, the blood supply system of the large arteries of the head and neck is not closed, and its components are interconnected through anastomoses - special connections that allow blood vessels to communicate without forming a network of arterioles. In the human body, the largest number of anastomoses is formed by the main artery of the brain - the internal carotid. This organization of blood supply allows you to maintain constant movement of blood through the circulatory system of the brain.

Structurally, the arteries of the neck and head are different from the arteries in other parts of the body. First of all, they do not have an external elastic shell and longitudinal fibers. This feature increases their stability during jumps. blood pressure and reduces the force of blood pulsation impulses.

The human brain works in such a way that at the level of physiological processes it regulates the intensity of blood supply to structures nervous system. This is how it works defense mechanism body – protecting the brain from surges blood pressure And oxygen starvation. The main role in this is played by the sinocartoid zone, the aortic depressor and the cardiovascular center, which is associated with the hypothalamic-mesancephalic and vasomotor centers.

Anatomically, the largest vessels bringing blood to the brain are the following arteries of the head and neck:

Carotid artery. It is a paired blood vessel that originates in chest from the brachiocephalic trunk and aortic arch, respectively. At the level thyroid gland, it, in turn, is divided into internal and external arteries: the first delivers blood to the medulla, and the other leads to the facial organs. The main branches of the internal carotid artery form the carotid basin. Physiological significance The carotid artery is responsible for supplying microelements to the brain; about 70-85% of the total blood flow to the organ flows through it.
Vertebral arteries. IN cranium form the vertebrobasilar pool, which provides blood supply to the posterior sections. They begin in the chest and along the bone canal spinal region The central nervous system travels to the brain, where it unites into the basilar artery. According to estimates, the blood supply to the organ through the vertebral arteries supplies about 15-20% of the blood.

The supply of microelements to the nervous tissue is ensured by the blood vessels of the circle of Willis, which is formed from the branches of the main blood arteries at the bottom of the skull:

two forebrains;
two midbrain;
pairs of hindbrain;
anterior connecting;
pairs of rear connecting ones.

The main function of the circle of Willis is to ensure stable blood supply during blockage of the leading vessels of the brain.

Also in the circulatory system of the head, experts identify the Zakharchenko circle. Anatomically, it is located on the periphery of the medulla oblongata and is formed by the union of the collateral branches of the vertebral and spinal arteries.

The presence of separate closed systems of blood vessels, which include the Circle of Willis and the Zakharchenko Circle, makes it possible to maintain the supply of the optimal amount of microelements to the brain tissue when blood flow in the main channel is disrupted.

The intensity of blood supply to the brain of the head is controlled using reflex mechanisms, the functioning of which is controlled by nerve pressoreceptors located in the main nodes of the circulatory system. For example, at the site of the branching of the carotid artery, there are receptors that, when excited, can give a signal to the body that it needs to slow down. heartbeat, relax the walls of the arteries and lower blood pressure.

Venous system

Along with arteries, the veins of the head and neck participate in the blood supply to the brain. The task of these vessels is to remove metabolic products from nervous tissue and control blood pressure. The venous system of the brain is much longer than the arterial system, which is why its second name is capacitive.

In anatomy, all veins of the brain are divided into superficial and deep. It is assumed that the first type of vessels serves as a drainage of the decay products of the white and gray matter of the terminal section, and the second type removes metabolic products from the structures of the trunk.

A cluster of superficial veins is located not only in the meninges, but also extends into the thickness of the white matter up to the ventricles, where it unites with the deep veins of the basal ganglia. Moreover, the latter entangle not only ganglia trunk - they are also sent to the white matter of the brain, where they interact with external vessels through anastomoses. Thus, it turns out that the venous system of the brain is not closed.

The superficial ascending veins include the following blood vessels:

The frontal veins receive blood from the upper part of the terminal section and send it to the longitudinal sinus.
Veins of the central sulci. They are located on the periphery of the Rolandic gyri and run parallel to them. Their functional purpose is to collect blood from the middle and anterior cerebral arteries.
Veins of the parieto-occipital region. They differ in branching in relation to similar structures of the brain and are formed from a large number of branches. They supply the blood to the posterior part of the terminal section.

The veins draining blood in a descending direction will unite into the transverse sinus, the superior petrosal sinus and the vein of Galen. This group of vessels includes the temporal vein and the posterior temporal vein - they send blood from the same parts of the cortex.

In this case, blood from the lower occipital zones of the terminal section enters the inferior occipital vein, which then flows into the vein of Galen. From the lower part of the frontal lobe, the veins run to the inferior longitudinal or cavernous sinus.

Also, the middle cerebral vein, which is neither an ascending nor a descending blood vessel, plays an important role in collecting blood from brain structures. Physiologically, its course is parallel to the line of the Sylvian fissure. At the same time, it forms a large number of anastomoses with branches of the ascending and descending veins.

Internal connection through anastomosis of deep and external veins allows the removal of cell metabolic products in a roundabout way when one of the leading vessels is insufficiently functioning, that is, in a different way. For example, venous blood from the superior Rolandic fissures in healthy person departs into the superior longitudinal sinus, and from the lower part of the same convolutions into the middle cerebral vein.

The outflow of venous blood from the subcortical structures of the brain goes through large vein Galena, in addition, venous blood from corpus callosum and cerebellum. The blood vessels then carry it to the sinuses. They are peculiar collectors located between the structures of solid meninges. Through them it is directed to the internal jugular (jugular) veins and through the reserve venous outlets to the surface of the skull.

Despite the fact that sinuses are continuations of veins, they are different from them anatomical structure: their walls are formed from a thick layer connective tissue with a small amount of elastic fibers, which is why the lumen remains inelastic. This structural feature of the blood supply to the brain promotes the free movement of blood between the meninges.

Impaired blood supply

The arteries and veins of the head and neck have a special structure that allows the body to control blood supply and ensure its consistency in the structures of the brain. Anatomically, they are designed so that in a healthy person, with an increase in physical activity and accordingly, the movement of blood increases, the pressure inside the vessels of the brain remains unchanged.

The process of redistribution of blood supply between the structures of the central nervous system is carried out by the middle section. For example, with increased physical activity, blood supply to motor centers increases, while in others it decreases.

Due to the fact that neurons are sensitive to a lack of nutrients, and especially oxygen, disruption of blood flow to the brain leads to a malfunction of certain parts of the brain and, accordingly, a deterioration in a person’s well-being.

For most people, a decrease in the intensity of blood supply causes following signs and manifestations of hypoxia: headache, dizziness, cardiac arrhythmia, decreased mental and physical activity, drowsiness and sometimes even depression.

Disruption of cerebral blood supply can be chronic and acute:

A chronic condition is characterized by insufficient provision of brain cells with nutrients for a certain amount of time, with a smooth course of the underlying disease. For example, this pathology may be a consequence of hypertension or vascular atherosclerosis. This may subsequently cause gradual destruction of gray matter or ischemia.
An acute disruption of blood supply or stroke, unlike the previous type of pathology, occurs suddenly with sharp manifestations of symptoms of poor blood supply to the brain. Usually this condition lasts no more than a day. This pathology is a consequence of hemorrhagic or ischemic damage to the brain substance.

Diseases due to circulatory disorders

In a healthy person, the middle part of the brain regulates blood supply to the brain. It also controls human breathing and endocrine system. If he stops receiving nutrients, then the fact that a person’s blood circulation to the brain is impaired can be identified by the following symptoms:

frequent attacks of headache;
dizziness;
difficulty concentrating, memory impairment;
the appearance of pain when moving the eyes;
the appearance of tinnitus;
absence or delayed reaction of the body to external stimuli.

To avoid development acute condition experts recommend paying attention to the organization of the arteries of the head and neck of certain categories of people who, hypothetically, may suffer from a lack of blood supply to the brain:

Children born with the help caesarean section and those who experienced hypoxia during intrauterine development or during labor.
Teenagers are going through puberty, as their body undergoes some changes at this time.
People engaged in increased mental work.
Adults who have diseases accompanied by depletion of peripheral blood flow, for example, atherosclerosis, thrombophilia, cervical osteochondrosis.
The elderly, since their vessel walls are prone to accumulation of deposits in the form cholesterol plaques. Also due to age-related changes the structure of the circulatory system loses its elasticity.

To restore and reduce the risk of developing serious complications from subsequently impaired cerebral blood supply, experts prescribe medications aimed at improving blood flow, stabilizing blood pressure and increasing the flexibility of vascular walls.

Despite the positive effect drug therapy, these medications should not be taken on your own, but only with a prescription, since side effect and an overdose threatens to worsen the patient’s condition.

How to improve blood circulation in the brain at home

Poor blood circulation to the brain can significantly worsen a person’s quality of life and cause more serious illnesses. Therefore, you should not ignore the main symptoms of the pathology and at the first manifestations of a blood supply disorder, you should contact a specialist who will prescribe competent treatment.

Along with the use medications he can also offer additional measures to restore the organization of blood circulation throughout the body. These include:

daily morning exercises;
simple physical exercises aimed at restoring muscle tone, for example, when sitting for long periods of time and in a hunched position;
a diet aimed at cleansing the blood;
use medicinal plants in the form of infusions and decoctions.

Although the content useful substances in plants is negligible compared to medicines, they should not be underestimated. And if a sick person uses them independently as a preventive measure, then you should definitely tell the specialist about this at the appointment.

Folk remedies for improving cerebral blood supply and normalizing blood pressure

I. The most common plants that have a beneficial effect on the functioning of the circulatory system are the leaves of periwinkle and hawthorn. To prepare a decoction of them, 1 tsp is required. pour a glass of boiling water over the mixture and bring to a boil. Afterwards it is left to infuse for 2 hours, after which half a glass is consumed 30 minutes before meals.

II. A mixture of honey and citrus fruits is also used for the first symptoms of poor blood supply to the brain. To do this, grind them into a pasty state, add 2 tbsp. l. honey and leave in a cool place for 24 hours. For a good result, you need to take this drug 3 times a day, 2 tbsp. l.

III. A mixture of garlic, horseradish and lemon is no less effective for vascular atherosclerosis. In this case, the proportions of mixing the ingredients may change. Take it 0.5 tsp. an hour before meals.

IV. Another surefire remedy for improving poor blood supply is an infusion of mulberry leaves. It is prepared as follows: 10 leaves are poured into 500 ml. boiling water and let it brew in a dark place. The resulting infusion is consumed instead of tea every day for 2 weeks.

V. When cervical osteochondrosis as an addition to the prescribed therapy, rubbing can be done cervical spine spine and head. These measures increase blood flow in the vessels and accordingly increase blood supply to brain structures.

Gymnastics is also useful, including exercises for moving the head: bending to the side, circular movements and holding your breath.

Drugs to improve blood circulation

Poor blood supply to the brain of the head is a consequence of serious pathologies of the body. Typically, treatment tactics depend on the disease that causes difficulty in blood movement. Most often, blood clots, atherosclerosis, poisoning, infectious diseases, hypertonic disease, stress, osteochondrosis, vascular stenosis and their defect.

In some cases, to improve blood circulation in the brain, drugs are used that act to relieve the main manifestations of the pathology: headache, dizziness, excessive fatigue and forgetfulness. In this case, the drug is selected so that it has a comprehensive effect on brain cells, activates intracellular metabolism, and restores brain activity.

When treating poor blood supply, the following groups of drugs are used to normalize and improve the organization of activity: vascular system brain:

Vasodilators. Their action is aimed at eliminating spasm, which leads to an increase in the lumen of blood vessels and, accordingly, a rush of blood to the brain tissue.
Anticoagulants, antiplatelet agents. They have an anti-aggregation effect on blood cells, that is, they prevent the formation of blood clots and make it more fluid. This effect helps to increase the permeability of the walls of blood vessels and, accordingly, improves the quality of supply of nutrients to the nervous tissue.
Nootropics. They are aimed at activating the brain due to increased cellular metabolism, while the person taking such drugs experiences a rush vitality, the quality of functioning of the central nervous system improves, interneuronal connections are restored.

Taking oral medications in people with minor disorders of the organization of the circulatory system of the brain helps stabilize and even improve them physical state, while patients with severe circulatory disorders and pronounced changes in the organization of the brain can be brought to a stable state.

To choose from dosage form Medicines are influenced by a large number of factors. Thus, in patients with severe manifestations of brain pathology, to improve blood supply, preference is given to intramuscular and intravenous injections, that is, with the help of injections and droppers. At the same time, to consolidate the result, prevent and treat the borderline state medicines consumed orally.

On the modern pharmacological market, the bulk of drugs for improving cerebral circulation sold in tablet form. These are the following medications:

Vasodilators:

Vasodilators. Their effect is to relax the walls of blood vessels, that is, relieve spasm, which leads to an increase in their lumen.

Correctors of cerebral circulation. These substances block the absorption and removal of calcium and sodium ions from cells. This approach prevents the work of spasmodic vascular receptors, which subsequently relax. Drugs with this effect include: Vinpocetine, Cavinton, Telektol, Vinpoton.

Combined cerebral circulation correctors. They consist of a set of substances that normalize blood supply by enhancing blood microcirculation and activating intracellular metabolism. They are the following drugs: Vasobral, Pentoxifylline, Instenon.

Calcium channel blockers:

Verapamil, Nifedipine, Cinnarizine, Nimodipine. Focused on blocking the flow of calcium ions to the tissues of the heart muscle and their penetration into the walls of blood vessels. In practice, this helps to reduce the tone and relaxation of arterioles and capillaries in peripheral parts vascular system of the body and brain.

Nootropics:

Drugs that activate metabolism in nerve cells and improve thought processes. Piracetam, Phenotropil, Pramiracetam, Cortexin, Cerebrolysin, Epsilon, Pantocalcin, Glycine, Actebral, Inotropil, Thiocetam.

Anticoagulants and antiplatelet agents:

Medicines intended to thin the blood. Dipyridamole, Plavix, Aspirin, Heparin, Clexane, Urokinase, Streptokinase, Warfarin.

A frequent culprit of “hunger” of brain structures is atherosclerosis. This disease is characterized by the appearance of cholesterol plaques on the walls of blood vessels, which leads to a decrease in their diameter and permeability. Subsequently, they become weak and lose their elasticity.

statins prevent the body from producing cholesterol;
sequestrants fatty acids, blocking the absorption of fatty acids, while they force the liver to spend reserves on the absorption of food;
vitamin PP - dilates the vascular duct, improves blood supply to the brain.

Prevention

As a complement to the main treatment, preventing the underlying disease will help improve blood supply to the brain.

For example, if the pathology was caused by increased blood coagulation, then establishing drinking regime. To achieve a positive effect, an adult needs to consume 1.5 to 2 liters of fluid daily.

If poor blood supply to brain tissue was caused by stagnation in the head and neck area, then in this case, doing basic exercises will help improve your well-being physical exercise to improve blood circulation.

All the steps below must be done carefully, without unnecessary movements or jerks.

In a sitting position, place your hands on your knees and keep your back straight. Straightening your neck, tilt your head to both sides at an angle of 45%.
This is followed by rotation of the head to the left, and then in the opposite direction.
Tilt your head forward and back so that your chin first touches your chest and then looks up.

Gymnastics will allow the muscles of the head and neck to relax, while the blood in the brain stem begins to move more intensely through the vertebral arteries, which provokes an increase in its flow to the structures of the head.

You can also stabilize blood circulation by performing a head and neck massage with improvised means. So, you can use a comb as a handy “trainer”.

Eating rich foods organic acids can also improve blood circulation in the brain. Such products include:

Fish and seafood;
oats;
nuts;
garlic;
greenery;
grape;
bitter chocolate.

Quite a lot important role plays in recovery and improvement of well-being healthy image life. Therefore, you should not get carried away with eating fried, highly salted, smoked foods, and you should completely stop drinking alcohol and smoking. It is important to remember that only A complex approach will help improve blood circulation and improve brain activity.

Video: Wallisian circle and Zakharchenko circle

The delivery of oxygen to the brain through the blood is one of the most important processes in the body. Thanks to him nerve cells receive the necessary energy for their functioning. It is not surprising that this system is quite complex and extensive. So, let's consider the blood supply to the brain, the diagram of which will be discussed in the article below.

Structure (briefly)

If we briefly consider the blood supply to the brain, it is carried out with the participation of the carotid arteries, as well as the vertebral arteries. The former provide about 65% of all blood, and the latter - the remaining 35%. But in general, the blood supply scheme is much broader. It also includes the following structures:

vertebrobasilar system;
special circle of Willis;
carotid basin.

In total, about 50 ml of blood per 100 g of brain tissue enters the brain per minute. It is important that the volumes and speed of blood flow are constant.

Blood supply to the brain: diagram of the main vessels

So, as already mentioned, 4 arteries supply blood to the brain. It is then distributed to other vessels. Let's look at them in more detail.

Internal carotid arteries

These are branches of the large carotid arteries, which are located on the side of the neck. They can be easily felt as they pulsate quite well. In the area of the larynx, the carotid arteries diverge into external and internal branches. The latter passes through the cranial cavity and carries oxygen to different areas of the blood supply to the brain. As for the external arteries, they are needed to supply oxygen to the skin and muscles of the face, as well as the neck.

Vertebral arteries

They begin with the subclavian arteries and pass through various parts of the cervical vertebrae, then entering the cranial cavity through an opening in the back of the head.

These vessels are characterized by high pressure and significant blood flow speed. Therefore, they have characteristic curves in the area where they meet the skull to reduce both pressure and speed. Further, all these arteries connect in the cranial cavity and form the arterial circle of Willis. It is necessary in order to compensate for the disturbance in any part of the blood flow and prevent oxygen starvation of the brain.

Cerebral arteries

The branches of the internal carotid artery are divided into the middle and anterior branches. They go further into the cerebral hemispheres and nourish their outer and inner surfaces, including the deep parts of the brain.

The vertebral arteries, in turn, form other branches - the posterior cerebral arteries. They are responsible for feeding the occipital areas of the brain, the cerebellum, and the trunk.

Subsequently, all these arteries branch into many thin arteries, digging into the brain tissue. They may vary in diameter and length. The following arteries are distinguished:

short (used to feed the bark;
long (for white matter).

There are other sections in the cerebral blood flow system. Thus, the BBB, a mechanism for controlling transport between capillaries and nervous tissue cells, plays an important role. The blood-brain barrier prevents foreign substances, toxins, bacteria, iodine, salt, etc. from entering the brain.

Venous drainage

The removal of carbon dioxide from the brain is carried out through a system of cerebral and superficial veins, which then flow into venous formations - sinuses. The superficial cerebral veins (inferior and superior) transport blood from the cortical part of the cerebral hemispheres, as well as from the subcortical white matter.

Veins, which are located deep in the brain, collect blood from the ventricles of the brain and subcortical nuclei, capsule. Later they unite into the common cerebral vein.

Having collected in the sinuses, the blood flows into the vertebral and internal jugular veins. In addition, diploic and emissary cranial veins participate in the blood outflow system.

It should be noted that the cerebral veins do not have valves, but many anastomoses are present. Venous system The brain differs in that it allows for ideal blood flow in a confined space of the skull.

There are only 21 venous sinuses (5 unpaired and 8 pairs). The walls of these vascular formations are formed from processes of solid MO. If you cut through the sinuses, they form a characteristic triangular lumen.

So, circulatory system The brain is a complex structure with many different elements, which have no analogues in other human organs. All these elements are needed in order to quickly and in the right quantity deliver oxygen to the brain and remove waste products from it.

Under physiological conditions, every 100 g of brain tissue at rest receives 55–58 ml of blood in 1 min and consumes 3–5 ml of oxygen. That is, the brain, the mass of which in an adult is only 2% of body weight, receives 750 - 850 ml of blood, almost 20% of all oxygen and approximately the same amount of glucose in 1 minute. A constant supply of oxygen and glucose is necessary to preserve the energy substrate of the brain, the normal functioning of neurons, and maintain their integrative function.

The brain is supplied with blood by two paired main arteries of the head - the internal carotid and vertebral. Two-thirds of the blood is supplied to the brain by the internal carotid arteries and one-third by the vertebral arteries. The former form the carotid system, the latter the vertebral-basilar system. The internal carotid arteries are branches of the common carotid artery. They enter the cranial cavity through the internal opening sleepy channel temporal bone, enter the cavernous sinus (sinus cavernosus), where they form an S-shaped bend. This part of the internal carotid artery is called the siphon, or cavernous part. Then it “pierces” the dura mater, after which the first branch departs from it - the ophthalmic artery, which, together with the optic nerve, penetrates into the cavity of the orbit through the optic canal. The posterior communicating and anterior villous arteries also depart from the internal carotid artery. Lateral from the chiasm optic nerves internal carotid artery divides into two terminal branches: the anterior and middle cerebral arteries. The anterior cerebral artery supplies blood to the anterior part of the frontal lobe and the inner surface of the hemisphere, the middle cerebral artery supplies a significant part of the cortex of the frontal, parietal and temporal lobes, the subcortical nuclei and most of the internal capsule.

Diagram of blood supply to the brain:

1 - anterior communicating artery; 2 - posterior cerebral artery; 3 - superior cerebellar artery; 4 - right subclavian artery; 5 - brachiocephalic trunk; 6 - aorta; 7 - left subclavian artery; 8 - common carotid artery; 9 - externalcarotid artery; 10 - internal carotid artery; 11 - vertebral artery; 12 - posterior communicating artery; 13 - middle cerebral artery; 14 - anterior cerebral artery

System cerebral vessels with the most important anastomoses:

I - aorta; 2 - brachiocephalic trunk; 3 - subclavian artery; 4 - common carotid artery;

5 - internal carotid artery; 6 - external carotid artery; 7 - vertebral arteries; 8 - main artery; 9 - anterior cerebral artery; 10 - middle cerebral artery;

II - posterior cerebral artery; 12 - front
communicating artery; 13 - rear connection
body artery; 14 - ophthalmic artery;

15 - central retinal artery; 16 - external maxillary artery

The anterior communicating artery connects the anterior cerebral arteries, and the middle and posterior cerebral arteries are connected by the posterior communicating artery. As a result of the connection of the vessels of the carotid and vertebral-basilar basins, a closed system is formed on the lower surface of the cerebral hemispheres - the arterial (Willisian) circle of the cerebrum.

There are four levels of collateral arterial blood supply to the brain. This is the system of the arterial (Willisian) circle of the cerebrum, the system of anastomoses on the surface and inside the brain - through the capillary network between the branches of the anterior, middle and posterior cerebral arteries, the extracranial level of anastomoses - between the branches of the extra- and intracranial vessels of the head.

Collateral blood supply to the brain plays an important role in compensating for circulatory disorders in the event of blockage of one of the cerebral arteries. At the same time, numerous anastomoses between different vascular beds can also play a negative role in relation to the brain itself. An example of this would be cerebral steal syndrome.

It should also be noted that there are no anastomoses in the subcortical region, therefore, if one of the arteries is damaged, irreversible changes occur in the brain tissue in the area of its blood supply.

The vessels of the brain, depending on their functions, are divided into several groups.

The main, or regional, vessels are the internal carotid and vertebral arteries in the extracranial section, as well as the vessels of the arterial circle. Their main purpose is to regulate cerebral circulation in the presence of changes in systemic blood pressure (BP).

The arteries of the pia mater (stray) are vessels with a clearly expressed nutritional function. The size of their lumen depends on the metabolic needs of the brain tissue. The main regulator of the tone of these vessels are the metabolic products of brain tissue, especially carbon monoxide, under the influence of which brain vessels dilate.

Intracerebral arteries and capillaries, which directly provide one of the main functions of cardio-vascular system, exchange between blood and brain tissue are “exchange vessels”.

The venous system primarily performs drainage function. It is characterized by a significantly larger capacity compared to the arterial system. Therefore, the veins of the brain are also called “capacitive vessels”. They do not remain a passive element of the vascular system of the brain, but take part in the regulation of cerebral circulation.

Through superficial and deep veins the brain from the choroid plexuses and deep parts of the brain there is an outflow of venous blood into the direct (through the great cerebral vein) and other venous sinuses of the dura mater. From the sinuses, blood flows into the internal jugular veins, then into the brachiocephalic and superior vena cava.

The functioning of the brain is entirely dependent on its continuous supply of oxygenated blood. Control of blood delivery occurs due to the ability of the brain to detect pressure fluctuations in the main sources of its blood supply - the internal carotid and vertebral arteries. Oxygen tension control arterial blood provides a chemosensitive zone medulla oblongata, the receptors of which respond to changes in gas concentrations breathing mixture in the internal carotid artery and cerebrospinal fluid. The mechanisms regulating the blood supply to the brain are delicate and perfect, but if the arteries are damaged or occluded by an embolus, they become ineffective.

A) Blood supply to the anterior parts of the brain. The blood supply to the cerebral hemispheres is carried out by two internal carotid arteries and the main (basilar) artery.

The internal carotid arteries penetrate through the roof of the cavernous sinus into the subarachnoid space, where they give off three branches: the ophthalmic artery, the posterior communicating artery and the anterior choroid plexus artery, and then divide into the anterior and middle cerebral arteries.

Main artery on upper limit The pons divides into two posterior cerebral arteries. The arterial circle of the brain - the circle of Willis - is formed by anastomosis of the posterior cerebral and posterior communicating arteries on both sides and anastomosis of the two anterior cerebral arteries using the anterior communicating artery.

The blood supply to the choroid plexus of the lateral ventricle is provided by the anterior artery of the choroid plexus (a branch of the internal carotid artery) and the posterior artery of the choroid plexus (a branch of the posterior cerebral artery).

The brain is supplied with blood by two paired main arteries of the head - the internal carotid and vertebral. Two-thirds of the blood is supplied to the brain by the internal carotid arteries and one-third by the vertebral arteries. The former form the carotid system, the latter the vertebrobasilar system. The internal carotid arteries are branches of the common carotid artery. They enter the cranial cavity through the internal opening of the carotid canal of the temporal bone, enter the cavernous sinus (sinus cavemosus), where they form an S-shaped bend. This part of the internal carotid artery is called the siphon, or cavernous part. Then it “pierces” the dura mater, after which the first branch departs from it - the ophthalmic artery, which, together with the optic nerve, penetrates into the cavity of the orbit through the optic canal. The posterior communicating and anterior villous arteries also depart from the internal carotid artery. Lateral to the optic chiasm, the internal carotid artery divides into two terminal branches: the anterior and middle cerebral arteries. The anterior cerebral artery supplies blood to the anterior part of the frontal lobe and the inner surface of the hemisphere, the middle cerebral artery supplies a significant part of the cortex of the frontal, parietal and temporal lobes, the subcortical nuclei and most of the internal capsule.

Figure 26.

The cerebral vascular system with the most important anastomoses:

1- anterior communicating artery;
2 - posterior cerebral artery;
3 - superior cerebellar artery;
4 - right subclavian artery;
5- brachiocephalic trunk;
6 - aorta; 7 - left subclavian artery; 8 - common carotid artery;
9 - external carotid artery;
10 - internal carotid artery;
11 - vertebral artery;
12 - posterior communicating artery;
13 - middle cerebral artery;
14 - anterior cerebral artery

I - aorta; 2 - brachiocephalic trunk;

3 - subclavian artery; 4 - common carotid artery; 5 - internal carotid artery; 6 - external carotid artery;
7 - vertebral arteries; 8 - main artery; 9 - anterior cerebral artery; 10 - middle cerebral artery;

II - posterior cerebral artery;

12 - anterior communicating artery;
13 - posterior communicating artery;
14 - ophthalmic artery; 15 - central retinal artery; 16 - external maxillary artery

The vertebral arteries arise from the subclavian artery. They enter the skull through openings in the transverse processes of the CI-CVI vertebrae and enter its cavity through the foramen magnum. In the area of the brain stem (pons), both vertebral arteries merge into one spinal trunk - the basilar artery, which divides into two posterior cerebral arteries. They supply blood to the midbrain, pons, cerebellum and occipital lobes of the cerebral hemispheres. In addition, two spinal arteries (anterior and posterior), as well as the posterior inferior cerebellar artery, depart from the vertebral artery. The anterior communicating artery connects the anterior cerebral arteries, and the middle and posterior cerebral arteries are connected by the posterior communicating artery. As a result of the connection of the vessels of the carotid and vertebral-basilar basins, a closed system is formed on the lower surface of the cerebral hemispheres - the arterial (Williziev) circle of the cerebrum (Fig. 27).

Fig.27.

The vessels of the brain, depending on their functions, are divided into several groups.

Intracerebral arteries and capillaries, which directly provide one of the main functions of the cardiovascular system, the exchange between blood and brain tissue, are “exchange vessels”.

The venous system primarily performs a drainage function. It is characterized by a significantly larger capacity compared to the arterial system. Therefore, the veins of the brain are also called “capacitive vessels”. They do not remain a passive element of the vascular system of the brain, but take part in the regulation of cerebral circulation. Through the superficial and deep veins of the brain, from the choroid plexuses and deep parts of the brain, venous blood flows into the direct (through the great cerebral vein) and other venous sinuses of the dura mater. From the sinuses, blood flows into the internal jugular veins, then into the brachiocephalic and superior vena cava.