about the project
Medical news
For authors
Licensed books on medicine
<< Previous Next >>

How vessels work

So what is vegetative-vascular dystonia? In plain language, this is a violation of the tone of the blood vessels - arteries, veins, capillaries - which occurred as a result of disturbances in the functioning of the autonomic nervous system. The human cardiovascular system is a clearly streamlined mechanism that is constantly in motion. The heart, contracting, jerks the blood into the aorta - the largest blood vessel, and then into the arteries. Arteries, in turn, also contract and relax in a certain rhythm, directing blood further throughout the body. This is due to the fact that the walls of the arteries have a muscular structure and thus compensate for the sharp shock of the heart so that the blood flows smoothly further.

Arteries branch as they move away from the heart, their diameter becomes smaller, and they pass into the so-called arterioles - the smallest vessels that are in front of the capillaries. They have a thick wall and a narrow clearance, and this structure allows them to resist the general blood flow - that is why arterioles are called resistance vessels, or resistive vessels.

And finally, the last link in the delivery of gases, nutrients and trace elements to tissues is capillaries, which are short tubes with very thin walls that can no longer contract. There are a huge number of them in the body, and they are responsible for the metabolism between blood and interstitial fluid. After all, blood passing through the capillary has time to exchange its contents up to 40 times with intercellular fluid. In the process, she gives away the substances necessary for the body and “collects” unnecessary ones. The better this metabolism proceeds, the more nutrition organs and tissues receive. Capillaries are called exchange vessels.

For normal nutrient delivery to tissues, maintaining a certain level of blood pressure is necessary. The amount of blood pressure depends on the force with which the blood presses on the walls of blood vessels or on the flow of blood from the center to the periphery. In different vessels, the pressure value will be different. So, the blood pressure in the capillaries (capillary pressure) should be significantly lower than in large arteries. The height of blood pressure depends on the strength of the heart contractions and the volume of blood that is ejected into the aorta, as well as on the degree of contraction of the small arteries and capillaries; It is also important how flexible the large vessels are.

The pressure drop in large and small vessels is very large (compare: 120-150 mm Hg for the arteries and 10-15 mm Hg for the capillaries), despite the fact that they are all directly connected - some go into others. This is due to the fact that in the cardiovascular system there is a mechanism due to which the walls of arteries (vessels of the so-called muscle type) are reduced. This mechanism impedes the movement of blood from large vessels into the capillaries, so the pressure in both parts of the connected and unified cardiovascular system varies so much.

To understand the mechanism of blood vessels, we are most interested in resistive vessels, or vessels of resistance. They contain only 3% of the total volume of our blood, but they, due to their structure, play the main role in the occurrence of pressure drops in the body. The walls of arterioles and capillaries are constantly in good shape, but they can change the diameter of the lumen under the influence of neurohumoral influences. How does this happen? What causes the vessels to expand and contract?

First of all, these are the laws of hydrodynamics (or hemodynamics, i.e. blood movements). The muscle fiber of the vessel responds to the amount of blood that has entered the vessel. If there is a lot of it, the vessel expands. But since the sheath of resistive vessels does not stretch well, blood pressure on the vessel wall increases.

The narrowing or expansion of blood vessels largely depends on the intake of minerals - calcium, magnesium and potassium. For example, a lack of potassium leads to an increase in blood pressure; Also, a high content of free calcium in the blood can increase the resistance of the walls of blood vessels and, as a consequence, increase pressure.

The narrowing and expansion of blood vessels depends on the influence of hormones. Some substances, such as adrenaline and norepinephrine, produced by the adrenal medulla, have the ability to affect vascular contraction. The walls of the vessels of resistance are expanded and contracted by the sympathetic nervous system. It regulates the release of more or less adrenaline and norepinephrine, which also transmit nerve impulses in the receptors of the sympathetic nerves. The latter send an impulse to the tissues, including the walls of the resistance vessels.

An essential role in the regulation of the activity of the heart and blood vessels is played by special protein formations on the cell membrane - receptors, which are many in the walls of blood vessels and in the heart muscle.
Receptors respond even to minor changes in tissue metabolism, and if tissues are not adequately supplied with nutrients, receptors quickly transmit information about this to the cerebral cortex. Further, the corresponding impulses are sent from the central nervous system, which cause vasodilation, which ensures enhanced heart function, and also increases the supply of food to organs and tissues.

So, we see how complex even in a healthy person is the regulation of the heart and blood vessels. But what is the picture if functional disturbances occur in the cerebral cortex and nervous system?

In the human nervous system, such departments as the somatic nervous system and the autonomic nervous system are distinguished.

In the somatic nervous system, the central (brain and spinal cord) part and the peripheral (nerves extending from them to various organs) are distinguished.

VVD is associated with impaired functioning of the autonomic part of the nervous system and arises due to an imbalance between its parts - the sympathetic and parasympathetic departments. The sympathetic nervous system is involved in the regulation of the activity of internal organs and activates the processes associated with the decay of energy. A parasympathetic, on the contrary, activates the processes of accumulation of energy and substances in the body. Changes due to failures in the management of the tone of these departments lead to the development of the IRR syndrome. Both increase and decrease in blood pressure (BP) are perhaps the most frequent manifestations of disorders of the physiological systems and internal organs, because pressure is always the result of accurately calculated joint activity of the heart and blood vessels.

In a healthy person, the cardiovascular system instantly responds to changing external conditions and provides all organs and systems with the nutrients necessary for them.

When they say that “all diseases are from the nerves”, then this directly relates to the IRR. Often, the control of the activity of the heart and blood vessels through the nervous and hormonal systems is disturbed as a result of neurosis. This violation just received a special designation in medicine: "neurocirculatory dystonia."

The connection between the nervous system and the vascular apparatus is very close, therefore, using special devices recording the expansion and narrowing of blood vessels, one can determine excitement, anxiety or other human experiences (the lie detector is based on this principle).

However, with painful changes, the activity of the cardiovascular system is disturbed. These changes and disorders resulting from a particular harmful effect on the nervous system can be very diverse. Moreover, one and the same reason can cause disturbances both in the work of the heart, and in the work of blood vessels or of individual sections of the vascular system. Most often, these disorders, as already mentioned, are manifested in the form of an increase or decrease in blood pressure.

Take, for example, such a destructive factor as stress. Strong negative emotions (anger, fear, despair) cause an increase or decrease in blood pressure. These short-term malfunctions in blood pressure are quickly compensated by auto-regulation of the body. But if no protective measures are taken, and stress for everyday reasons is aggravated and becomes constant, a person may wear out these regulatory systems, that is, depressor (relaxing) mechanisms that are not designed for frequent and prolonged use.

If the influence of stress factors continues, the safety depressor apparatus begins to perceive another malfunction in the functioning of blood vessels as a habitual, constant phenomenon. The body "gets used" to the new conditions and adapts to them. As a result of violation of blood pressure, failures in other systems are becoming more significant and prolonged.

However, the nerve center, which is subjected to constant loads, can react in another way - not to stop resisting stress, but to increase resistance and create a “guard ring” around itself. This, of course, will well protect the "defending" nerve center, but it will deprive it of the ability to properly regulate the activities of the "organs" entrusted to it.

These are two options for the development of primary IRR. Both in the first and in the second case, the vascular tone is reduced, but in the first it is simply the lack of tone, and in the second - blocks and spasms. Accordingly, drug treatment of these two options should be carried out in different ways. In addition, there is a third mechanism of VVD associated with a violation of the neurohumoral regulation of cardiac activity. Often these three mechanisms can be combined.
<< Previous Next >>
= Skip to textbook content =

How vessels work

  1. How to keep a table and how to work in each case?
    1. With farsightedness (if you wear glasses for near), keep it in front of your eyes at a distance of 15-20 cm. 2. If you have myopia (that is, you wear glasses for distance) - at arm's length. In case of weak myopia, when at this distance you see the last line in the table well, fix the table on the wall and find your working line. And how to do this, read below. 3. Who is bad
  2. How the program works
    Today, everywhere you look, interest in purification is growing. Thanks to an active exchange of information between individuals on the Internet and numerous articles and recommendations on detoxification, the situation was more confusing than ever. Descriptions of extreme methods can scare away many. In addition, a few days after the start of their chosen program, people
  3. How does our fairy tale work?
    Here's an example of a continuation of a fairy tale written by Medunitsa: Okay, said Serenade Marzipanovna. You can always make lemonade from lemon! Not in the sense that she decided to take up the production of soft drinks and compete with Pinocchio, which has been flourishing in this field for decades. And in the sense that she was not going to give up. Serenade took her
  4. What is a table for vision and how to work with it?
    A training chart for correcting vision is an indicator of the correctness of your work with emotions, that is, it is needed for control. The table itself will not give you anything - it's just a piece of paper. Do not expect a miracle from her, create it yourself! Your task is to direct 90% of your efforts to “muscle corset” and mood. All! Hold the “muscle corset” and raise your mood until
  5. How to be a wife who does not work and is completely dependent on her husband?
    From your question, I realized that you are no longer accepting the fact that you are dependent on your husband. Are you interested in how the spouse himself relates to this state of affairs? Do you understand what is really going on in the depths of your soul? Have you tried to share your feelings with your husband about this situation? You need to realize that in this world, everyone helps someone, but
    On palpation of the common carotid, humeral, ulnar, temporal, femoral, popliteal, and rear art stops, the tasks are narrowed down to an approximate assessment of the pulsatory movements by voltage and filling. The carotid artery is palpated on the left and right in a delicate way, removing the sternoclavicular-nipple muscle outwards at the level of the thyroid cartilage, palpating the facts of the common carotid artery on the left and right.
  7. At work, I have a big burden of responsibility. I head the department, which employs 30 employees. And specific tasks are set for me. I must constantly monitor the implementation of these tasks. How can I be responsible for such a number of employees without experiencing stress and not considering it a heavy burden?
    First, you need to check if you have a clear commitment to your boss. Have you made a clear commitment to complete one or more tasks on a specific date? Are these tasks realistic? And if you do not fulfill the tasks set for you, what will be the consequences? Are you ready to take responsibility for them? Having a clear from the start
    Forms of organization of medical assistance for workers in industrial enterprises, in construction and in transport. Workers can receive medical assistance: In special medical institutions organized directly at enterprises: medical centers, factory (workshop) clinics, medical and feldsher health centers); In the "workshop therapeutic areas" of clinics of the general network; In total
  9. Clinical examination of workers
    The main purpose of the clinical examination is the prevention and reduction of the incidence of disease, the active implementation of wide health-improving measures to improve health, increase active creative longevity, eliminate the causes of diseases, as well as various preventive examinations aimed at identifying common diseases - oncological, cardiovascular, tuberculosis, and
  10. What works must eat
    The reserve reserves intended for use during fasting are assimilated with greater ease and less load on the body compared to the consumption of food undergoing a difficult process of assimilation. Dr. Jennings explained: “The moment concerning the vessels of the lymphatic system deserves special attention and reminder. For some health problems when the digestive apparatus is removed
    Mothers always work and breastfeed. Women at the pioneers on the prairie did a lot of things, in addition to feeding their children, and even modern mothers, who are at home during the day, doing housework, often replenish the family budget, despite the fact that they take care of their babies. Martha fed our first child, Jim, and at the same time worked as a nanny for part of the day. In 1967
  12. Psychologist working with bank staff
    Almost all of us have been to a state or commercial savings bank and came across its employees. We have seen how much different work they perform, and this work cannot be called easy and entertaining, so a person must have certain personal qualities in order to occupy this post. Indeed, in addition to the endless operation with documents, they have to communicate
  13. Fairy tales. Working with parallel space
    One of the methods of working with parallel space is fairy tales. Any problem in a fairy tale can easily be described and solved - and you will be surprised how quickly, solved in parallel space, it solves itself both in RMB and in reality. Compose your own fairy tale, or pick our magic one, and lose, live it, as if you yourself composed everything, or change the plot to the desired
  14. Why do some pictures work, while others do not?
    Over the years, helping people solve problems with pictures, I was often surprised that some types of pictures helped clarify the situation, while others only worsened understanding. This is not related to picture quality. For example, the people in diagram A were drawn much more accurately than the outlines of the figures in diagram B, but this did not help make diagram A easier to understand. It didn’t have
  15. Preliminary and periodic medical examinations of employees
    Preliminary and periodic metro-USSR (No. 555 of September 29, 89). According to this, medical examinations are regulated by an order approved: by order of the Ministry of Health 1) a list of dangerous, harmful substances and adverse production factors, when working with which inspections are required to prevent occupational diseases; 2) a list of works for which inspections are required
    Mapping thinking does not eliminate thinking itself, but facilitates it. Practice organizing your thoughts with colors and
  17. Hygienic characteristics of working conditions and the health status of workers in the production of antibiotics
    Working conditions in the production of antibiotics are characterized by the possible entry into the air of fine dust of antibiotics, vapors and gases used in the technological process of chemicals and the release of excess heat. At the fermentation stages, workers may be exposed to phenol and formaldehyde vapors used to sterilize rooms and equipment, as well as dust
Medical portal "MedguideBook" © 2014-2019