Arteries of the brain: types and functions. Anatomy of the brain
As is known, for the normal operation of the central nervous system, in particular the brain, the level of oxygen and the amount of glucose is extremely important. These substances are delivered to the nerve tissues along with blood. And the transport system in this case is the arteries of the brain. Today, many people are interested in more information about the system of blood supply to the brain. Which vessels carry blood to the central nervous system? How is the outflow of blood? What symptoms are accompanied by a violation of blood flow? What diagnostic measures are most effective? What is the difference between CT and MRI of the brain? How do you eliminate blood circulation problems and can you do it yourself? The answers to these questions will be interesting.
For the normal functioning of the human brain requires a sufficient amount of resources. In particular, the central nervous system is extremely sensitive to the level of oxygen and sugar in the blood. About 15% of all circu
There are four main arteries of the brain that fully meet the needs of this body: two vertebrates and two internal carotid. Of course, it is worth considering the anatomical features of the body. What areas of the brain's blood supply exist? What happens when blood flow is disturbed?
Internal carotid artery
These vessels are carotid artery branches( common).As is known, common carotid arteries( right and left) are located in the lateral sections of the neck. If you put your fingers to the skin, then through the tissues you can easily feel the characteristic pulsation of the vascular walls. Approximately at the level of the larynx, the common carotid artery branched into the outer and inner. The inner penetrates through the hole in the skull, supplies blood to the brain tissue and eyeballs. The external carotid artery is responsible for the blood supply to the skin of the head and neck.
Considering the arteries of the brain, it is impossible not to mention the vertebral arteries. They branch off from the subclavian arteries, after which they pass through the holes of the transverse processes of the cervical vertebrae, and then penetrate into the cranial cavity through the occipital opening. It is worth noting that after entering the cranial cavity, the vessels connect to each other, forming a very specific arterial circle.
The connecting artery of the Willis circle is a kind of "security system".If blood flow in one of the vessels is disturbed, then due to the presence of the arterial circle, the load is redirected to other, healthy arteries. This helps maintain blood circulation in the brain at the right level, even if one of the vessels is out of order.
Brain arteries branch from the internal carotid artery. The front and middle vessels provide nutrition to the deep brain areas, as well as the surfaces of the cerebral hemispheres( internal and external).There are also posterior vertebral arteries, which are formed by branching off vertebral arteries. These vessels carry blood to the cerebellum and brainstem. Large cerebral arteries diverge, forming a mass of small vessels that sink into the nerve tissues, providing their nourishment. According to statistics, cerebral hemorrhages in most cases are associated with a violation of the integrity of the above-described vessels. What is the blood-brain barrier?
In modern medical practice, a term such as the blood-brain barrier is often used. It is a kind of transport and filtration system that prevents certain compounds from entering the capillaries directly into the nerve tissue. For example, substances such as salt, iodine and antibiotics do not normally enter the brain tissue. That is why during the treatment of brain infections, antibacterial drugs are injected directly into the cerebrospinal fluid - so an antibiotic can penetrate into the brain tissue.
On the other hand, alcohol, chloroform, morphine and some other substances easily penetrate the blood-brain barrier, which explains their intense and almost instantaneous effect on the brain tissue.
Carotid basin: features of anatomy
This term refers to the complex of the main carotid arteries, which originate in the thoracic cavity( including branch off from the aorta).The carotid pool provides blood to most of the brain, skin and other structures of the head, as well as the visual organs. Violation of the functioning of the structures of this basin is dangerous not only for the nervous system, but for the whole organism. The cause of problems with blood circulation is most often atherosclerosis. This ailment is associated with the formation of a kind of plaques on the internal walls of the vessels. Against the backdrop of atherosclerosis, the lumen of the vessel narrows, the pressure in it increases. Development of the disease is associated with a number of dangerous consequences, including embolism, ischemia and thrombosis. These pathologies in the absence of timely treatment can result in the death of the patient.
In modern medical practice, a term such as the vertebro-basilar system, or Zakharchenko's circle, is often used. It is a complex of vertebral vessels. The structure of the structure includes the basilar artery. Vertebrate vessels, as already mentioned, originate in the thoracic cavity, and then pass through the channels of the cervical vertebrae and reach the cavity of the skull. The basilar artery is an unpaired vessel that is formed by connecting vertebral arteries. This part of the bloodstream provides nutrition to the posterior parts of the brain, including the cerebellum, the medulla oblongata, and part of the dorsal.
The lesions of the vessels described above( beginning with mechanical injuries and ending with atherosclerosis) often end with thromboses. Disruption of the blood supply of those brain structures that form this organ can lead to the appearance of various neurological symptoms and stroke.
Viena and the outflow of blood
Many people are interested in the question of how the arteries and veins of the brain work. We have already examined the ways in which blood flows to the brain. As for the outflow system, it is carried out through the veins. The upper and lower superficial veins collect blood from the subcortical layer of white matter and the cortical portion of the cerebral hemispheres. In the cerebral veins, blood is collected from the cerebral ventricles, inner capsule and subcortical nuclei. All the vessels described above subsequently flow into the venous sinuses of the hard shell of the brain. From the sinuses blood flows through the vertebral and jugular veins. With the external vessels, the sinuses are communicated via diplic and emissary veins. By the way, these vessels have some features. For example, veins that collect blood from brain structures are devoid of valves. There is also a large number of vascular anastomoses.
Blood flow in the structures of the spinal cord
The spinal cord receives blood from the anterior, two posterior and radicular-spinal arteries. The posterior spinal vessels give rise to the vertebral( spinal) artery - they are directed along the dorsal surface of the spinal cord. The anterior spinal artery is also an offshoot of the vertebral vessels - it lies on the anterior cerebrospinal surface.
The vessels described above feed only the first two or three cervical segments. The blood circulation of the rest of the spinal cord is due to the work of the radicular-spinal arteries. In turn, these vessels, which descend down and run along the entire spine, receive blood by communicating with the ascending cervical, intercostal and lumbar arteries. It should also be said that the spinal cord has a highly developed vein system. Small vessels take blood directly from the tissues of the spinal cord, and then flow into the main venous canals that run along the entire spine. From above they connect to the veins of the base of the skull.
Disorders of cerebral circulation
Considering the arteries of the brain, we can not fail to mention the pathologies that are associated with impaired blood circulation. As already mentioned, the human brain is extremely sensitive to oxygen and the level of sugar in the blood, so the deficit of these two components negatively affects the work of the whole organism. Prolonged hypoxia( oxygen starvation) leads to the death of neurons. The result of a sharp decline in glucose levels is loss of consciousness, coma, and sometimes death.
This is why the blood vessel of the brain is equipped with a kind of protective mechanisms. For example, the venous system is rich in anastomoses. If the outflow of blood is violated by one vessel, then it moves in a different way. The same applies to the Willis circle: if the current is broken on one artery, its functions are sorted by other vessels. It is proved that even if two components of the arterial circle do not work, the brain still gets enough oxygen and nutrients.
But even such a well-coordinated mechanism sometimes fails. The pathologies of cerebral vessels are dangerous, so it is important to diagnose them in time. Frequent headaches, periodic dizziness, chronic fatigue are the first symptoms of cerebral circulation disorders. If untreated, the disease can progress. In such cases, a chronic impairment of cerebral circulation, discirculatory encephalopathy develops. Over time, this ailment does not disappear - the situation is only aggravated. The lack of oxygen and nutrients leads to a slow death of neurons.
This, of course, affects the work of the whole organism. Many patients complain not only of migraine and fatigue, but also of noise in the ears, periodic pain in the eyes( for no apparent reason).Possible occurrence of mental disorders and memory impairment. Sometimes there is nausea, the appearance of tingling on the skin, numbness of the limbs. If we talk about acute disturbance of cerebral circulation, it usually ends in a stroke. This condition develops rarely - the heart rate increases, consciousness becomes confused. There are problems with coordination, there are problems with speech, divergent strabismus, paresis and paralysis develop( usually one-sided).
As for the causes, in most cases, the violation of blood flow is associated with atherosclerosis or chronic hypertension. Risk factors include spine diseases, in particular, osteochondrosis. Deformation of intervertebral discs often leads to displacement and compression of the vertebral artery, which nourishes the brain. Having noticed any of the above symptoms, immediately consult a doctor. If it is an acute circulatory failure, the patient needs immediate medical attention. Even a few minutes of delay can harm the brain and lead to a mass of complications.
CT and MRI of the brain
The price in Moscow( as in any other city) for such procedures is quite high. Therefore, many people are interested in additional information about similar diagnostic activities. These procedures are considered the most informative. So what is the difference between CT and MRI of the brain? In fact, the purpose of such procedures is the same - the scanning of the human body with the further construction of the image of the body "in a section."
Nevertheless, the operation scheme of the devices themselves is different. The work of ART equipment is based on the behavior of the hydrogen atom in a strong magnetic field. But with computer tomography, information about tissues and organs is obtained by special detectors that capture radio emission transmitted through the human body due to X-ray tubes. Both devices transmit all data to a computer that analyzes information, forming images.
How much will the MRI of the brain cost? Prices in Moscow fluctuate depending on the policy of the chosen clinic. The study of cerebral vessels will cost about 3500-4000 rubles. The cost of CT is slightly lower - from 2500 rubles.
By the way, these are not the only diagnostic measures that help to diagnose those or other disorders of blood flow. For example, a lot of useful information gives angiography of cerebral arteries. The procedure is carried out by introducing a special contrast agent into the vessels, the movement of which is then monitored with the help of X-ray equipment.
What medications are prescribed to improve the blood circulation of the brain? Drugs and the right diet
Unfortunately, many people face such a problem as a violation of the blood flow in the vessels of the brain. What to do in such cases? What medications are prescribed to improve the blood circulation of the brain? Drugs, of course, picks up the attending physician, and it is not recommended to experiment with such drugs on your own.
As a rule, therapies include drugs that prevent platelet aggregation and clotting. Positively on the state of nervous tissues, vasodilator drugs affect. Nootropics also help improve blood circulation and, accordingly, trophic tissue. If there is evidence, the doctor may prescribe a psychostimulant.
People at risk are encouraged to reconsider their lifestyle and, in the first place, food. Experts advise to include in the menu vegetable oils( linseed, pumpkin, olive), fish, seafood, berries( cranberries, cranberries), nuts, sunflower seeds and flax, bitter chocolate. It is proved that the regular use of tea affects the circulatory system positively.
It is important to avoid hypodynamia. The feasible and regular physical activity increases the flow of blood to the tissues, including the nervous ones. Positively on the circulatory system affects the sauna and sauna( in the absence of contraindications).Of course, in the presence of any violations and anxiety symptoms, it is worthwhile to see a doctor and undergo a medical examination.