IN last years vascular diseases are becoming more common. Due to blockage of the veins, death or disability is not uncommon. Correctly chosen method of treatment with the help of effective medications will help to get rid of these problems. Vascular drugs to improve blood circulation in the legs should be prescribed only by a specialist. This is how you can achieve a good result without harm to health. We will talk about the types of such drugs and their effect on the human body in this article.

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Funds classification

Due to vasoconstriction, various pathologies can develop in the cardiovascular system, in the limbs and other organs. Vasodilator drugs not only prevent destructive changes, but also help to quickly restore blood circulation and damaged tissues that have been subjected to hypoxia.

The most convenient and informative is the classification of drugs according to their mode of action. The most rapid vasodilating properties have the following medicines:

• Nitric oxide. Once in the bloodstream, the free radical instantly relaxes the muscles. The effect of this substance is short-lived, but very effective. It allows you to relieve vasospasm in a short time, for example, with angina pectoris, restore blood circulation and avoid a heart attack. Medicines that contain this substance: isosorbide dinitrate, nitroglycerin, nitrong-forte.
• Magnesium sulfate. Reduces the mobile activity of calcium ions, which are conductors of antispasmodic signals. Pushes them out of the space between cells. Reduces the excitability of adrenergic receptors, which also stimulate the contractile activity of the muscles. When injected into a vein, they quickly create a relaxing effect. The action is about half an hour.
• Antispasmodics. These include drugs that act simultaneously on the circulatory system and smooth muscle tissues throughout the body. The time of their therapeutic effect is approximately from 2 to 6 hours. It is based on the inactivation of an enzyme that stimulates smooth muscle contraction. The means of this type include: apressin, no-shpa and papaverine hydrochloride.

Medicines from the third group stabilize blood circulation, prevent spasm of veins and arteries. The scope of their influence extends to the blocking of enzymes or receptors that enhance muscle contraction.

Substances acting on the PNS

To drugs that eliminate circulatory disorders lower extremities, include ganglioblockers, sympatholytics and α-blockers. The first means act on the sympathetic nodes: the solar or deep plexus of the heart.

The list of effective drugs to improve blood circulation in the limbs:

• Benzohexonium;
• Pentamine;
• Quateron;
• Pyrilene.

The active ingredients contained in these drugs work well for circulatory disorders caused by pathologies of the nervous system (Raynaud's disease, endarteritis, acrocyanosis).

Adrenoblockers are substances that, when combined with adrenaline and norepinephrine, block their vasoconstrictive action. This improves blood circulation in the body. This group includes such drugs:

• Phentolamine, Prazosin, Terazosin;
• Vasobral, Nicergoline, Anavenol.

The last three drugs are used for varicose veins and for complications of diabetes mellitus (angiopathy). These substances are not exactly vasodilators, as they act in different directions - they increase the tone of the veins and dilate the arteries. The remaining drugs are effective in nervous pathologies with circulatory disorders, as well as in the treatment of legs affected by atherosclerosis.

Vasodilators

Vasodilation is a medical term used to describe a decrease in smooth muscle tone in the walls of blood vessels. Substances that are used for this are called vasodilators. This group includes many vasodilators with different mechanisms of action on the circulatory system.

calcium antagonists

For the normal operation of calcium channels (CC), in addition to Ca, catecholamines (adrenaline and norepinephrine) are needed, which activate them. There are several types of CK, but calcium ion antagonists only act on slow CK (L-type) that are found in smooth muscle tissues. Calcium channel antagonists are available in various chemical compounds. In addition to reducing the level of pressure, they also have the following effect:

1. Regulate the heart rate.
2. Good effect on blood circulation in the veins, arteries and capillaries.
3. Reduce mechanical stress in the myocardium, thereby improving blood circulation. It also increases the supply of tissues with oxygen and nutrients.
4. Reduce the likelihood of blood clots in the arteries and veins.

The most popular calcium antagonists are such drugs: Nifedipine, Amlodipine, Felodipine. They help reduce the tone of the walls of the circulatory organs and prevent their sharp contraction (spasm).

Alpha blockers

α-blockers block the adrenaline and norepinephrine receptors in the vessels, preventing them from interacting with these hormones that can cause significant vasospasm. This group includes:

• Nicergoline - improves blood circulation, prevents platelet adhesion and thrombosis. It has a dual effect: it promotes the expansion of the arteries and increases the tension of the veins (healthy and affected by varicose veins). The drug is indicated for use in vascular diseases associated with diabetes.
• Phentolamine - dilates blood vessels, relaxes muscles, increases blood supply to tissues. For the treatment of venous and arterial circulation disorders, the treatment of poorly healing wounds, frostbite, bedsores, and in the initial stage of atherosclerotic gangrene, doctors recommend this drug in the form of injections and tablets.

If there is a blockage of the vessel with an atherosclerotic plaque, then it is useless to use vasodilator drugs, surgical treatment is required.

RAS inhibitors

These substances affect the arteries and veins. They have a positive effect on the endothelium, reduce platelet aggregation, and inhibit the development of atherosclerosis. These drugs include: Enalapril, Lisinopril, Ramipril, Losartan. They showed nice results in the treatment of atherosclerotic pathologies of the legs and with intermittent claudication caused by the same cause.

Biogenic stimulants

Medicines belonging to the group of vasodilators for the treatment of the lower extremities. Their action is based on substances of animal origin. These medicines dilate the arteries of the legs, speed up blood circulation and improve tissue metabolism.

Solcoseryl

A medicine was made on a natural basis (an extract from the blood of calves freed from protein). The drug is able to increase metabolism in tissues, accelerate the supply of oxygen to the muscles of the limbs, dilates blood vessels and thereby improves blood circulation. It is prescribed by doctors in the form of injections.

Actovegin

Its basis is the same as that of the previous drug. Thanks to the substances that it contains, blood circulation improves, the vessels of the lower extremities expand, and ulcers and wounds quickly heal.

Comparative review of vasodilators

The sphere of influence of vasodilating elements is extensive. They are used in the treatment various pathologies peripheral circulation:

• varicose disease;
• with atherosclerosis;
• angiodystonia.

Below we consider the most commonly prescribed drugs by doctors.

halidor

Myotropic antispasmodic with pronounced vasodilating action. Available in tablets and solutions for intramuscular and intravenous administration. The active substance is bencyclane fumarate. It is prescribed for the treatment of diseases of the peripheral circulatory organs, chronic pathologies arteries and to relieve spasms in systems and tissues.

There are a number of contraindications, so you need to use the remedy only after the recommendation of a specialist.

Vinpocetine

This synthetic drug restores impaired blood circulation. Active substance- vinpocetine. It has antioxidant, antiepileptic and neuroprotective effects, and also dilates blood vessels and relieves inflammation. It is prescribed for the treatment of many vascular diseases, including in violation of motor activity associated with cerebrovascular insufficiency.

Vinpotropil

A nootropic combination drug that also has vasodilating properties. It is used for cerebrovascular insufficiency, prevention of migraines, Parkinson's disease of vascular etiology and other pathologies of the blood supply to the brain, and as a vasodilator for the legs, it is used only as part of complex therapy prescribed by a doctor.

Drug Warfarin-OBL

The active substance is warfarin. This drug is indicated in the treatment and prevention of thrombosis and thromboembolism. Is an anticoagulant indirect action. The decrease in coagulation is not due to the influence of the drug itself, but due to its pharmacological effects in the body, that is, in a secondary way.

The doctor may prescribe this drug to prevent or treat blood clots in the circulatory system and congenital thrombophilia (blood clots).

Vasoket

This medication is recommended by doctors for the treatment of veins. The therapeutic effect of the components extends mainly to the limbs. The main effect is aimed at improving the tone and elasticity of venous vessels and removing foci of blood stasis. Ancillary activities are:

• improvement of lymphatic drainage;
• regulation of general circulation;
• decrease in vascular permeability;
• regulation of the quality of leukocytes.

At the right doses, the drug has a directed and complex effect on the circulatory system. It has minor contraindications, which the doctor will take into account when prescribing.

Vasobral

A complex preparation, which includes caffeine and ergot alkaloids. It is used in pathologies of cerebral and peripheral blood circulation. The instructions for use say that it is able to increase the tone of the veins and restore capillary permeability.

Therefore, it is often prescribed for varicose veins and other circulatory pathologies.

Bilobil

The composition of this product contains extract of the leaves of ginkgo biloba. Available in capsules of 40, 80 and 120 mg. The herbal preparation is able to improve cerebral microcirculation, slightly dilates blood vessels, increases the resistance of tissues to hypoxia and reduces the ability of platelets to aggregate. The most effective drug acts on the veins and arteries of the arms, legs and cerebral vessels. The active substances of the drug also work as antioxidants.

Traditional medicine

Vascular pathology of the legs is not an independent disease. This is one of the signs bad condition organism. If in the last century problems with joints and blood vessels worried only the elderly, now young people are also concerned about them. In women, such lesions on the legs occur after childbirth.

In the early stages, these diseases do not manifest themselves in any way, so it is important to engage in prevention and eat only healthy foods, do simple exercises to improve the general condition and improve blood circulation in the vessels of the feet and calves. There are also effective folk methods for cleansing blood vessels at home. Let's describe some of them:

1. Strengthening blood vessels with cranberries. It is necessary to take half a kilogram of fresh red beets, cranberries, black radishes and 0.5 liters of alcohol. Grind these products and put in a three-liter glass jar. Then pour alcohol, cover with a lid and leave to infuse in a dark and cool room. After 15 days, strain, pour into a clean jar and store in the refrigerator. Drink 30 ml per day half an hour before breakfast.
2. Treatment of varicose veins with Kalanchoe leaves. Grind them, put them in a jar of 0.5 liters, the leaves should fill it halfway. Pour in water and insist in a dark place for 7 days. Shake the jar once a day. Strain the infusion and rub it on the legs at night (starting from the foot to the hips). The course of treatment is 1 month.
3. Rejuvenation of limbs with blueberries. Chop berries. Apply the resulting slurry to your feet for 1 hour. Wash off with water afterwards.
4. Cleaning vessels with lemon and garlic. This remedy will not only help cleanse the circulatory system, but also lower cholesterol levels and relieve headaches. Chop 4 lemons and 4 cloves of garlic. Stir and pour 2.5 liters of cold boiled water. Leave for 3 days in a jar with a lid. Treatment is long, but effective (from September 1 to May 30). Take 100 g in the middle of the day.

It is possible to cure not very advanced vascular diseases of the legs with folk remedies, but it is advisable to consult a specialist before that. After all, even a non-serious pathology can have Negative consequences Therefore, it must be done correctly and in a timely manner.

Everyone knows that the human body works fully if every smallest cell receives oxygen and nutrients in full. And for this, in turn, it is necessary to have a good functioning of the microcirculatory bed - the smallest vessels in the body, or capillaries. It is in them that the exchange of gases and nutrients between the blood and surrounding tissues occurs.

Approximately it looks like this - blood cells (erythrocytes) receive oxygen in the lungs, and thanks to an extensive network of vessels in all organs and tissues of the body, they deliver it to each organ. All intraorganic vessels are divided into ever smaller arteries, arterioles and, finally, capillaries, in which, thanks to the thinnest wall, gas exchange occurs between blood and organ cells. After the blood has “given away” oxygen to the cells, it collects waste products (carbon dioxide and other substances), which are delivered to the lungs through small and larger veins and are brought out with exhaled air. Similarly, the cells are enriched with nutrients, the absorption of which occurs in the intestine.

Thus, the functioning of vital organs - the brain, heart, kidneys, etc. depends on the state of the liquid part of the blood and the walls of the capillaries themselves.

Capillaries are represented by the thinnest tubes, the diameter of which is measured in nanometers, and the wall does not have a muscular membrane and is most suitable for diffusion of substances in both directions (into the tissue and back into the lumen of the capillaries). The blood flow rate and blood pressure in these small vessels is extremely slow (about 30 mm Hg), compared to large ones (about 150 mm Hg), which is also beneficial for a full gas exchange between blood and cells.

If, due to any pathological processes, the rheological properties of the blood, which ensure its fluidity and viscosity, change, or the wall of the vessels is damaged, then microcirculation disorders occur, which affect the supply of the cells of the internal organs with the most important substances.

Causes of microcirculation disorders

At the heart of such disorders are the processes of damage to the vascular wall, as a result, its permeability increases. Stagnation of blood develops and the release of its liquid part into the pericellular space, which leads to compression of small capillaries by an increased volume of intercellular fluid, and the exchange between cells and capillaries is disturbed. In addition, in the case when an integral capillary wall is damaged from the inside, for example, in atherosclerosis, as well as in inflammatory or autoimmune vascular diseases, platelets “stick” to it, trying to close the formed defect.

So, the main pathological conditions that lead to disruption of blood flow in the vessels of the microvasculature are:

• Pathology of the central organs of the circulatory system- acute and chronic heart failure, all types of shock (traumatic, pain, due to blood loss, etc.), myocardial ischemia, venous hyperemia (increase in blood volume and its stagnation in the venous part of the bloodstream).
• Pathological changes in the ratio of liquid and cellular parts of the blood- dehydration or, conversely, an increase in the volume of the liquid part of the blood with excessive fluid intake into the body, DIC with increased thrombus formation in the lumen of the vessels.
• Diseases of the vascular wall:
  1. Vasculitis (literally, vascular inflammation) - primary hemorrhagic, vasculitis in autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, rheumatism), vasculitis with hemorrhagic fevers and with bacteremia (sepsis - penetration of bacteria into the blood and generalization of infections),
  2. Atherosclerosis of large and small arteries, when atherosclerotic plaques are deposited on the inner wall of the vessels, preventing normal blood flow,
  3. Damage to the vascular wall and attachment of blood clots to it in diseases of the veins - with thrombophlebitis and phlebothrombosis,
  4. Diabetes mellitus, in which there is a toxic effect of excess glucose on the inner lining of blood vessels, ischemia (insufficient blood flow) of soft tissues develops.

What are the symptoms of such disorders?

Violations of blood microcirculation can occur in any organ. However, the most dangerous is the defeat of capillaries in the heart muscle, in the brain, in the kidneys and in the vessels of the lower extremities.

A heart

typical causes of impaired blood supply to the heart muscle (myocardium)

Microcirculation disorders in the heart muscle indicate the development of myocardial ischemia, or coronary heart disease. This chronic illness(IHD), the danger of which is the development of acute myocardial infarction, often fatal, as well as the formation of chronic heart failure, which leads to the fact that the heart is not able to supply blood to the entire body.

TO initial symptoms blood flow disorders in the myocardium include signs such as increased fatigue, general weakness, poor exercise tolerance, shortness of breath when walking. At the stage when severe myocardial ischemia develops, pressing or burning pains appear behind the sternum or in the projection of the heart on the left, as well as in the interscapular region.

Brain

Disorders of microcirculation in the vessels of the brain appears due to acute or chronic disorders of cerebral circulation. The first group of diseases includes strokes, and the second one develops as a result of long-term arterial hypertension, when the carotid arteries that feed the brain are in a state of increased tone, as well as due to lesions of the carotid arteries with atherosclerotic plaques or due to severe osteochondrosis of the cervical spine, when the cervical vertebrae put pressure on the carotid arteries.

cerebral ischemia due to impaired blood supply

In any case, when the nutrition of the brain cells is disturbed, as there is stagnation of blood and swelling of the intercellular substance, microinfarctions of the substance of the brain are possible. All this is called chronic dyscirculatory encephalopathy (CDEP).

Symptoms of DEP include changes in cognitive and mental functions, impaired emotional spectrum, forgetfulness, especially loss of everyday memory, touchiness, tearfulness, dizziness, unsteadiness of gait and other neurological symptoms.

kidneys

Microcirculation disorders in the vessels of the kidneys may occur as a result of acute or chronic processes. So, in a state of shock, blood does not enter the vessels of the kidneys, as a result of which an acute kidney failure. In chronic processes in the kidneys (arterial hypertension, vascular damage in diabetes mellitus, pyelonephritis and glomerulonephritis), capillary blood flow disorders develop gradually, throughout the entire period of the disease, and are clinically manifested, as a rule, by minor signs - rare urination, nocturia (urination at night). ), swelling on the face.

The acute condition is manifested by the absence of urine (anuria) or a sharp decrease in its amount (oliguria). Acute renal failure is an extremely dangerous condition, because without treatment, the body is poisoned by the products of its own metabolism - urea and creatinine.

lower limbs

Microcirculation disorders in the vessels of the lower extremities most often develop as a result of acute thrombosis of the arteries or veins of the lower extremities, as well as in diabetic angiopathy - damage to the microvasculature in patients with high level blood glucose. In addition, disorders of capillary blood flow in the muscles of the legs and feet occur in smokers due to constant spasm of the vessels of the corresponding vessels and are clinically manifested by the syndrome of intermittent claudication.

Acute blood flow disturbances in thrombosis are manifested by a sharp edema, blanching or blueness of the limb, and a pronounced pain syndrome in it.

Chronic microcirculation disorders, for example, with varicose veins of the lower extremities or diabetic angiopathy, are characterized by periodic pain, swelling of the feet, and impaired skin sensitivity.

The diabetic foot syndrome deserves special attention. This is a condition that develops as a result of prolonged damage to the vascular wall by glucose that is not absorbed by cells, as a result of which macro- and microangiopathy (vascular pathology) develops from minor to severe disorders.

lower limb ischemia and trophic disorders due to diabetes

Minor microcirculation disorders in diabetes are manifested by a crawling sensation, numbness and coldness of the feet, ingrown nails, fungal infection and cracks in the skin of the soles. Severe disorders develop as a result of the addition of secondary bacterial flora due to a decrease in local and general immunity and are manifested by long-term non-healing trophic ulcers. In severe cases, gangrene of the foot develops and even amputation of the feet may be necessary.

Leather

It is also worth mentioning microcirculation disorders in the vessels of the skin.

In the skin, changes in blood flow and, as a result, oxygen supply to cells occur not only in the indicated pathological conditions, for example, in the skin of the extremities with thrombosis or diabetes mellitus, but also in perfectly healthy individuals during skin aging processes. Moreover, premature aging can occur in young people and often requires close attention of cosmetologists.

So, there are variants of spastic, atonic and spastic-congestive disorders of blood flow in skin microvessels:

insufficiency of microcirculation in the skin

The first type is characteristic especially for persons with vegetative-vascular dystonia of the hypertensive type (when there is a tendency to spasm of large vessels with increased level blood pressure) and is characterized by spasm of small vessels with malnutrition of facial skin cells. As a result, gradually develops fine wrinkled type of aging– a network of wrinkles is formed all over the face, even in the ammic areas. risk factor premature aging This type is smoking.

• The second type is typical for persons with hypotonic dystonia (a tendency to low blood pressure) and is characterized by the appearance of microedema in the skin of the face, which is externally manifested not by wrinkles, but deformation type of skin aging- puffiness, spider veins and red spots on the face. The risk factor for premature aging in this type is obesity.
• The third type of changes in skin microcirculation has signs of both variants and is more often observed after 40-45 years.

Are microcirculatory disorders dangerous?

Undoubtedly, many microcirculation disorders are dangerous for the health and even the life of the patient, especially if they occur acutely. Thus, blood flow disturbances in the small vessels of the heart muscle that occurred during acute coronary thrombosis, lead to severe myocardial ischemia, and after a few minutes or hours - to necrosis (death) of heart muscle cells - develops acute infarction myocardium. The larger the affected area, the worse the prognosis.

In acute thrombosis of the femoral arteries and veins, any delay in terms of medical and surgical intervention can lead to loss of a limb.

The same applies to persons with diabetic angiopathy and diabetic foot syndrome. Such patients should be educated in the proper care of their feet so as not to lose their legs when developing a purulent infection or foot gangrene.

In the case of long-term processes in the body, for example, in violation of microcirculation in the kidneys and in the brain with hypertension, there is, of course, a violation of the function of the organ, but there is no acute threat to life.

Age-related disturbances in blood flow in the microvessels of the skin generally do not pose any danger to life and health, but only cause aesthetic problems.

Which doctor should I contact?

Blood microcirculation disorders are a common process, so the referral to a specific specialist depends on the presence of a primary pathology and clinical manifestations.

If you notice frequent or, conversely, rare urination, accompanied by high blood pressure numbers, as well as heart symptoms (chest pain, shortness of breath, heart failure), you should consult a general practitioner or a cardiologist.

With swelling, coldness and discoloration of the limbs (blanching, blue or redness), it is necessary to visit a vascular or at least a general surgeon. Diabetic foot syndrome is jointly treated by endocrinologists and surgeons.

Violations of the microcirculation of cerebral vessels due to strokes, hypertension or osteochondrosis of the spine (the so-called DEP of complex origin) is the prerogative of neurologists.

Cosmetologists and dermatologists deal with the correction of impaired blood flow in the skin and the associated skin aging.

Improving microcirculation, drugs that improve blood flow

Is it possible to somehow improve or restore blood flow in the smallest vessels of the body? The answer to this is yes, at the present stage of the development of medicine, there are enough means that can regulate the tone of blood vessels, as well as influence their inner wall and the ability of blood to form blood clots, and thus help improve microcirculation.

To improve blood circulation in the lower extremities The following groups of drugs are mainly used to improve microcirculation:

1. Antispasmodics (papaverine, spasmalgon) - relieve the tone of large and small vessels due to the effect on the smooth muscle layer in their wall,
2. Angioprotectors and antiplatelet agents (pentoxifylline (vasonite), trental, chimes) help to improve metabolic processes in the vascular wall itself, thereby stabilizing its permeability to the liquid part of the blood,
3. Biogenic stimulants (solcoseryl, actovegin) have a similar effect as protectors,
4. Vasodilators (nifedipine, amlodipine) also weaken vascular tone.
5. At acute conditions drugs are used that reduce blood clotting and prevent further thrombosis - anticoagulants (heparin, warfarin), antiplatelet agents (aspirin), fibrinolytics (urokinase, streptokinase, alteplase).

Improve microcirculation in the brain perhaps with the help of the same drugs, but the following are more often used - antispasmodics (drotaverine), vasodilators (cinnarizine, vinpocetine), antiplatelet agents (trental, chimes), microcirculation correctors (betahistine), as well as nootropic drugs(piracetam, nootropil), polypeptides (cortexin, cerebrolysin), gamma-aminobutyric acid preparations (pantogam, phenibut).

As microcirculation correctors for the heart muscle, in addition to these drugs, antioxidants and antihypoxants (mexidol, preductal) are highly effective, which not only improve blood flow in myocardial capillaries, but also increase the resistance of its cells to oxygen starvation (hypoxia).

Of the means that allow correcting microcirculation disorders in the kidneys, pentoxifylline, trental and chimes are more often prescribed.

For facial skin, the restoration of microcirculation consists mainly in the use of external cosmetic procedures, such as laser exposure to the skin, mesotherapy, installation of mesothreads, plasmolifting, peeling, massage, various masks with retinoids, and many other methods to improve microcirculation. All of them are able to stimulate the work of blood vessels in the skin so that the cells receive enough nutrients and oxygen.

In conclusion, it should be noted that blood flow disturbances in small vessels is a rather broad concept that includes a large number of diseases as causative factors. Therefore, only a doctor at an internal appointment should be engaged in the search for these factors, and patients who have some of the above symptoms should seek help from specialists.

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If a person's blood circulation is disturbed, then this is fraught with the development of a large number of diseases, some of which are very serious. The brain, blood vessels, heart are damaged, and after a while problems arise in other organs. Violation of the circulation of the legs can indicate hidden diseases, and the person does not even know about it. This pathological condition entails various consequences. So how can you improve circulation in your legs? Let's try to figure it out.

Signs of arterial and venous insufficiency

Damage to the veins and arteries (atherosclerosis), endarteritis, varicose veins, narrowing of the lumen of the vessels leads to impaired circulation in the lower extremities cholesterol plaques, inflammation of the walls of the vessel or its spasm. If suddenly blue “stars” or nets of thin vessels appear on the leg, then these are signs of the development of varicose veins, which can manifest itself as pain and heaviness in the legs, night cramps, swelling, knots and swelling on the affected vessels.

The skin on the legs may become red and thin. Circulatory disorders in the lower extremities are manifested by arching pains in the calves, heavy legs, intermittent lameness. More serious signs are thrombosis, trophic ulcers indicating the development of thrombophlebitis.

Causes of pathology

The main reason leading to impaired blood circulation in the lower extremities is a sedentary lifestyle. Most people, by the nature of their activities, are often in a sitting position, which leads to stagnation of blood in the veins. There is pain in the legs, they begin to get tired quickly and become cold.

Many people, especially the elderly, constantly feel a little chilly, but after a short walk they become hot. This is explained by the fact that even such a small physical activity increases blood circulation, relieving cold feet syndrome.

How to improve circulation in the legs? In this case, no special treatment is required, just a little change in your lifestyle is enough. If you start moving more, then the disease is able to go away on its own, and simple morning exercises will help improve the general condition of the body.

Other causes, and not so harmless, can also lead to impaired blood circulation in the lower extremities. Such a pathological condition may be a sign of the malfunctioning of any organ. That is why it can be difficult to figure out what specifically contributed to the development of the disease and what treatment is required.

The following are the most common causes of circulatory disorders in the legs:

• alcohol and smoking;
• age-related changes;
• high levels of cholesterol in the blood;
• ischemia, atherosclerosis;
• diabetes;
• hypertension;
• overweight;
• varicose veins, thrombosis and stenosis of the arteries.

Ways to deal with circulatory disorders

If no measures are taken to combat circulatory disorders, then after a certain period of time the legs will be mutilated with blue nodules and intertwined with swollen veins. There is also a high probability of damage to deep internal veins. Unfortunately, the pathological changes affecting the peripheral vessels are chronic and do not go away without treatment.

Doctors involved in the treatment of blood vessels have at their disposal various means that improve blood circulation in the legs. With the help of drugs and physiotherapeutic procedures, the pathological state of the veins and arteries of the lower extremities is reduced or eliminated. If these methods turn out to be ineffective, then they resort to such a radical method as an operation with the removal, cauterization or sclerosis of the affected area of ​​the vessel. But such surgical intervention is quite painful, and as a result, the cause of the deformation of the veins is not completely eliminated.

Medical treatment

Drugs that improve blood circulation in the legs should only be prescribed by a doctor. After questioning and external examination of the patient, he is sent for examination. Based on the results obtained, the doctor prescribes the necessary drugs to normalize blood circulation in the lower extremities. So how can you improve circulation in your legs? To do this, use the following tools:

• Angioprotectors. They are necessary to improve microcirculation, as well as normalize vascular permeability, due to which normal metabolic activity returns to the walls. These include Curantil, Persantin, Trental, Flexital, Doxy-Hem, Pentoxifylline, Radomin, Vazonite.
• Medicines of low molecular weight dextran. Thanks to such drugs, an additional volume of blood flows from the intercellular space into the bloodstream. As a result, blood flow is significantly improved. This category includes the following medications: Reomacrodex and Reopoliglyukin.
• Preparations containing prostaglandin E1 ("Vazaprostan"). Thanks to them, blood flow improves and microcirculation normalizes. These drugs also contribute to the expansion of blood tracts and normalization of blood pressure.
• Calcium channel blockers that even affect the vessels of the brain. These include: "Kordafen", "Kordaflex", "Adalat", "Stamlo", "Norvax", "Plendil", "Foridon", "Lacipil".
• Antispasmodics of myotropic action. With the help of such drugs, the vessels expand, and the blood begins to circulate freely. In addition, they relieve spasms well. Such medications are "Mydocalm", "Cavinton", "Eufillin", "Galidor".

Other medicines

How to improve circulation in the legs? For these purposes, other drugs are also used.

Bioflavonoids increase the elasticity of red blood cells, which improves blood flow. Ganglion blockers dilate venules, arterioles and small veins and evenly distribute blood volume in the lower extremities. Such drugs include "Dimekolin", "Kamfoniy", "Pahikarpin", "Temekhin", "Pirilen".

Also, this problem is solved by drugs such as alpha-blockers. They have a complex effect on the entire body, expanding the vessels not only in the lower extremities, but also in the internal organs.

The use of ointments

An ointment that improves blood circulation in the legs helps to relieve only swelling of the lower extremities, but the cause of its occurrence cannot be eliminated. The most popular remedies are the following external preparations:

• heparin ointment;
• "Venitan";
• "Essaven-gel";
• "Troxevasin" and others.

Traditional medicine

How to improve circulation in the legs? Folk remedies can help solve this problem only if the disease is mild. In more serious cases, medical attention is needed.

Bring the greatest effect alcohol tinctures lilac or chestnut flowers. To do this, the flowers are placed in a half-liter jar, filling it almost to the top, and poured with vodka or alcohol, diluted by half. The jar is closed with a plastic lid and placed in a dark place for two weeks. During this time, the liquid acquires dark brown color. It should be filtered, and then rubbed with it on the inner surface of the thighs and below.

For these purposes, chestnut fruits are also used, which are pre-flattened. Preparation and use of tincture is carried out in the same way.

How to improve blood circulation in the legs of the elderly? All of the above methods are effective for people of all ages.

Output

Thus, there are many ways to help improve blood circulation in the lower extremities. Treatment will be successful if a person has the will, perseverance and desire for this. To avoid such a pathological condition, preventive measures should be used.

Peripheral circulation is a continuous process of blood circulation in small veins and arteries, capillaries, as well as arterioles and venules. A variety of factors lead to a violation of blood circulation, among them: tumors, injuries, diseases of the heart and blood vessels, kidney disease, metabolic disorders, etc.

Signs of impaired circulation can be: pain in the legs, swelling, discoloration of the limbs, headaches, hearing problems, imbalance, numbness of the limbs, etc.

Treatment of impaired circulation

With impaired circulation, the following diseases occur:

• arterial and venous hyperemia
• thrombosis
• ischemia
• embolism
• varicose veins
• Raynaud's disease

For treatment, it is necessary to accurately determine the cause and, depending on it, prescribe medication. In acute disorders, surgery may be required. In addition, treatment must be combined with proper nutrition (eat food with low content fat and salt), give up bad habits (smoking and alcohol) and undergo special procedures to improve blood flow (vibration therapy, electromagnetic therapy, etc.).

Drugs to improve blood circulation

The following groups of drugs are used to improve blood circulation:

1) Drugs that improve microcirculation - this group of drugs acts on the vessels of the microcirculatory bed. As a result, the vessels dilate, and the blood becomes less viscous. As a rule, drugs of this group are used for circulatory disorders against the background of various diseases (diabetes mellitus, atherosclerosis):

• radomin
• chimes
• pentoxifylline
• trental
• vasonite

2) Prostaglandin E1 preparations - drugs of this group have a positive effect on microcirculation and blood flow, and also have a hypotensive effect:
vazaprostan

3) Calcium channel blockers are mainly used to improve blood circulation in the brain. Contribute to the improvement of vascular microcirculation and limit damage to brain tissue. These include:

• cinnarizine
• logmax
• nafadil
• nimotop
• cinnasan
• brainal
• norvax
• arifon
• cordipin
• foridon
• nifecard
• cordafen

4) Low molecular weight dextran preparations - drugs of this group have a positive effect on blood fluidity, by attracting additional blood volumes from the intercellular space. These include:

• rheomacrodex
• hemostabil
• rheopolyglucin

5) Myotropic antispasmodics - this group of drugs dilates blood vessels and relaxes smooth muscles. Myotropic antispasmodics show high efficiency in spasms of cerebral vessels:

• spasmol
• halidor
• mydocalm

6) Phytopreparations - preparations that are created on the basis of plant materials. Phytopreparations show high efficiency in diseases of the cerebral vessels, as well as in obliterating atherosclerosis and endarteritis. These include:

• bilobil
• tanakan

7) Alpha-blockers - drugs of this group contribute to better blood supply peripheral tissues. These include:

• phentolamine
• prazosin
• sermion

Ganglioblockers - these drugs improve blood circulation in the lower extremities, and also have a pronounced hypotensive effect (lower blood pressure):

• pyrylene
• temehin
• dimecolin
• pachycarpine

9) Bioflavonoids - substances of plant origin that increase blood flow and improve the condition of blood vessels:

• venoruton
• anthoxide

10) Dopamine receptor stimulants - this group of drugs has an effect on dopamine receptors, which, in turn, leads to vasodilation. Improve blood circulation in the lower extremities - pronoran.

Diabetes mellitus often accompanies leg diseases. Disorders associated with complete or partial occlusion of the vessels of the lower extremities occur in 30-35% of patients. How older age patient, the more likely they are to appear.

Causes of circulatory disorders

In people with diabetes, the lower limbs hurt due to blockage of blood vessels by atherosclerotic plaques. Insufficient lumen of capillaries exposed to pathological changes, does not allow sufficient supply of tissues with blood.

Therefore, they experience severe discomfort due to a lack of nutrients, oxygen and send a kind of signal for help in the form of pain manifestations.

Atherosclerosis of the lower extremities develops due to the high content of sugar in the bloodstream. The concentration of glucose negatively affects the circulatory system, depositing excess substances on the walls of blood vessels, weakening them and depriving them of elasticity. The disease creeps up gradually, and can go unnoticed for many years.

Knowing the main symptoms that manifest themselves at different stages of the disease will help to recognize the pathology in time:

• the skin on the patient's legs thickens, acquires shine;
• nails become brittle;
• there is hair loss in the lower leg area;
• there is partial atrophy of the muscles of the legs;
• ulcers may appear on the heels and toes;
• sometimes gangrene of the fingers develops;
• in the lower extremities there are sensations of pain or tingling (numbness, weakness) during walking or physical activity;
• feeling of chilliness and coldness in the legs;
• cramps in the calf muscles;
• discoloration of the skin of the legs (excessive pallor, redness).

Often the patient's complaints may be non-specific or absent altogether. In half of the cases, vascular pathologies of the lower extremities do not manifest themselves in any way. They can only be diagnosed during the examination. If treatment is not started promptly, it may be necessary surgical correction diseases, that is, amputation of one of the limbs.

Treatment

If treatment is not started in time, non-stenosing atherosclerosis of the legs can easily turn into a more severe stenosing phase of the disease, characterized by swelling and tissue atrophy, blockage of the veins, and, as a result, gangrene.

Even in the case when the lumen of the vessel is completely closed by cholesterol deposits, the blood still circulates through the collateral branches, so the symptomatic picture may not be clear.

Medical preparations

The treatment regimen largely depends on the severity of vascular damage, the duration of the disease and the stage at which it is at the time of treatment, as well as the presence of comorbidities. What medications are used to treat the lower limbs in case of violation of normal blood circulation in them?

List of drugs:

1. Antiplatelet agents for the prevention of blockage of blood vessels and their treatment, such as Aspirin, Reopoliglyukin.
2. Vascular dilating drugs, for example, Vasonit, Vasaprostan, Trenal and others.
3. Drugs that increase physical endurance - Pentoxifylline and Cilostazol, which improve blood circulation and make it easier for the patient to walk.
4. Drugs that reduce the content of "bad" cholesterol in the blood.
5. Anticoagulants that thin the blood, such as Warfarin, Heparin.
6. Antispasmodics, for example, Drotaverine. Neutralize vasospasm, reduce pain.
7. Drugs that increase blood circulation in tissues, this can be Zincteral and others.
8. Fibrates, such as Bezafibrate, Clofibrate, are prescribed to diabetics to reduce the amount of triglycerides.
9. To regulate cholesterol levels, statins are prescribed: Lovastatin, etc.
10. Ointment based on antibacterial agents(Levomekol, Dimexide), treats trophic ulcers on the legs.
11. Vitamin complexes.
12. A nicotinic acid.
13. Physical procedures, for example, electrophoresis and others as prescribed by a doctor.

American scientists proposed to introduce the prevention of atherosclerosis with aspirin and β-blockers to all people who have reached the age of 45. Such measures, according to foreign doctors, are necessary even if there are no obvious signs of atherosclerosis.

ethnoscience

With herbal remedies, the disease can be cured only at the very beginning of its development. In all other cases, admission natural preparations should be carried out in combination with the main drug treatment as aids. The use of any medicinal substances from the arsenal of traditional medicine should be agreed with the attending physician and not contradict the main treatment.

A few folk recipes:

1. To restore the blood supply to the legs, you can apply the following treatment option. Need to dial pine needles, preferably from the branches of the first year, but this is possible. Grind raw materials, pour into a 3 l saucepan, and fill more than half of the container. Pour boiling water over everything. After 2 hours, drain the water into a separate bowl, and again pour boiling water over the needles and cook for five minutes. Filter the broth and combine with the previously prepared infusion. Take 1/4 cup of the treatment solution, adding honey to it, twenty minutes before meals. You need to drink this remedy for a long time, not one month. The first results will appear in three weeks.
2. Ordinary cucumbers from the home garden will help get rid of blood clots in the peripheral vessels of the legs. When the ripening of the vegetable begins, it is necessary to collect it and grate it or chop it in another way, for example, in a blender. Then squeeze out the juice. Do this every day, drinking 3-4 glasses on an empty stomach. Continue treatment throughout the cucumber season, until its very end.
3. Another plant from our garden has an antiplatelet effect. Dry carrot tops to last for the whole year. In season, fresh herbs can be used to prepare a decoction. Boil a handful of tops in a liter saucepan for no more than five minutes. Then you need to wrap everything up and insist for about an hour, then filter and drink 150 ml of broth, which should be done half an hour before meals.
4. It is very useful on an empty stomach to drink a mixture of juices with honey added to them: apple-carrot, beet-carrot, carrot-celery and carrot-garlic. Drink juices three-quarters of a glass three times a day.
5. Vascular pathologies of the legs respond well to treatment with various bee products: propolis, royal jelly, honey, which are combined with bee stings, as well as appropriate herbal remedies.

Massage, acupuncture

To restore the normal functioning of the legs, doctors recommend massage and rubbing. Such procedures are carried out using a special ointment that penetrates deep into the skin of the extremities and helps relieve inflammation, swelling and pain, improve poor blood circulation in the vessels of the legs.

Massage should begin with the foot, gradually moving to the lower leg and thigh. At first, the movements are calm, then they become more intense, gradually stroking is replaced by kneading. During the day, it is necessary to massage the sore limbs about five times. The duration of one session is about ten minutes. Such a simple system of massage and rubbing makes it possible to achieve significant success in the treatment of the disease.

Foot massage video tutorial:

Treatment of atherosclerosis can be carried out with the help of oriental medicine, for example, acupuncture. This method allows you to quite successfully activate blood circulation in the relevant organs. In this case, the body is not exposed to various chemicals, as in drug treatment.

Physical exercise

Therapeutic exercise also helps to increase impaired blood flow in the legs. The load at the beginning of classes, as a rule, should be moderate, the pace of exercise should be comfortable for the patient. The basis of the treatment complex is the implementation of exercises in which the legs are involved, the swings of which must be performed with a large amplitude.

Japanese healers suggest doing the following exercise. It is necessary to choose a suitable place where you can lie on your back, while the surface should not be soft. Put something under the neck area. Then raise your arms and legs. Feet should be up and parallel to the floor. Three minutes you need to shake all the limbs. Therapeutic impact on the capillaries occurs due to vibration.

Alternate walking on toes and on heels is very useful for the vessels of the legs. This exercise stimulates the blood to move more intensively.

By doing squats, you can strengthen the muscle tissue of the entire leg. In this case, it is necessary to ensure that the foot is, as it were, "glued" to the floor.

Video lesson with exercises to improve blood circulation:

Proper nutrition

One of the means of combating the disease is proper nutrition. For a diabetic, this is doubly important. Given the GI of products, a diabetic patient should monitor blood glycemic indicators so as not to provoke the appearance of new complications.

The diet is compiled in such a way that there is a gradual decrease in the patient's diet of animal fats, simple carbohydrates, salt, and stimulants.

Very useful product in this disease is cabbage. It removes excess cholesterol, saturates the body with plenty of vitamin C.

Using in combination all the ways and means to improve blood circulation, you can quickly achieve results and gain good health, and with it a better and more positive life.

Microcirculatory bed is a complexly organized system that carries out the exchange between blood and tissues, which is necessary to ensure cellular metabolism and remove metabolic products. The microcirculation system is the first link that is involved in the pathological process under various conditions. extreme situations. In the microcirculatory bed, a link is isolated for the inflow and distribution of blood, which includes arterioles and precapillary sphincters, an exchange link formed by capillaries, a deposit link consisting of postcapillary vessels and venules, which has a capacity 20 times greater than arterioles, a drainage link - lymphatic capillaries and postcapillaries.

Pathology of the microvasculature includes vascular, intravascular and extravascular changes. Vascular changes, referred to as "angiopathy", are violations of the thickness, structure and shape of the vessel, affecting its permeability and transcapillary exchange. Intravascular changes are manifested primarily in various violations of the rheological properties of blood, aggregation and deformation of its cellular elements. When they aggregate with blood plasma separation (sludge phenomenon), the blood flow velocity decreases, arterioles become blocked, which leads to the appearance of plasma capillaries, devoid of erythrocytes and not providing a full-fledged transcapillary exchange. Similar disorders occur with DIC, shock of various origins, acute infectious processes, coagulopathy consumption.

Extravascular changes are expressed by the development of perivascular edema, hemorrhages and lead to lymphostasis, desolation and regeneration of lymphatic capillaries. The level of microcirculation is the key one in the cardiovascular system, while the other levels are designed to provide its main function - transcapillary exchange. The liquid part of the blood, oxygen dissolved in it and substances necessary for tissue metabolism, leave the vascular space in the capillary system. This transport is carried out according to the laws of diffusion and is determined by the gradient of intra- and extravascular hydraulic pressure, which contributes to fluid extravasation, and the gradient of intra- and extravascular oncotic pressure, which ensures fluid retention in the vascular bed and return of interstitial fluid into it. In accordance with the ratio of these gradients, fluid diffuses in the arterial part of the capillary and its reabsorption occurs in the venous part. With an average capillary pressure of 20 mm Hg. Art., the pressure at the arterial end of the capillary reaches 30 mm Hg. Art., in the venous - 15 mm Hg. Art. Since the hydraulic pressure in the tissues is 8 mm Hg. Art., then the filtration pressure in the arterial knee of the capillary is 22 mm Hg. Art., in the venous - 7 mm Hg. Art. The difference in oncotic pressure between blood and tissues is 15 mm Hg. Art., therefore, the excess of hydraulic pressure over the oncotic at the arterial end of the capillary ensures the release of fluid outside the vessel, and the excess of oncotic pressure over the hydraulic at the venous end is about 8 mm Hg. Art. leads to the return of fluid into the bloodstream.

Since oncotic blood pressure under normal conditions is a relatively constant value, the determinant of the intensity of transcapillary metabolism and, accordingly, the provision of nutritional needs of tissues is capillary hydrostatic pressure, and its establishment and maintenance is the main task that other parts of the cardiovascular system solve. With working hyperemia against the background of expansion of resistive vessels and an increase in the speed of blood flow, blood pressure in the capillaries increases with increased blood filtration; this is accompanied by an increase in hematocrit, which ensures an adequate supply of oxygen to the tissues. At rest, an increase in the tone of resistive vessels is accompanied by a decrease in blood flow, a decrease in capillary pressure, an increase in tissue fluid reabsorption, a decrease in hematocrit, and the transformation of part of the capillaries into plasma, that is, devoid of erythrocytes.

Capillary hydraulic pressure is not always a reflection of systemic blood pressure and in pathological situations it can change regardless of changes in blood pressure. Paralytic expansion of arterioles leads to an increase in capillary pressure even against the background of reduced blood pressure, resulting in increased extravasation of the liquid part of the blood, its thickening and progressive impairment of peripheral circulation. If, under normal conditions, the value of capillary pressure is associated primarily with the tone of the precapillary resistive vessels that regulate blood flow, then in pathological conditions, the difficulty in outflow of blood from the capillaries may come first due to contraction or mechanical compression of the postcapillary discharge vessels - venules and veins. A similar effect is noted during the transition of shock, in particular cardiac shock, from a reversible phase to an irreversible one, when, against the background of dilated arterioles, spasm of postcapillary resistive vessels leads to an increase in capillary pressure, filtration of the liquid part of the blood and its thickening, followed by a sharp violation of microcirculation.

In the microcirculation system, the most important role in maintaining tissue perfusion is played by rheological properties of blood, its "fluidity". Any liquid is characterized by such a concept as "viscosity", since the liquid column moves through the tube not as a single unit, but in separate layers that move relative to each other. This is the so-called laminar or layered current, which is characterized by a direct relationship between the driving force, which is the pressure of the liquid, and the speed of its movement. Due to the presence of molecular cohesive forces between the individual layers of the flow, internal friction develops, the severity of which determines the viscosity of the liquid. As a result, individual layers will move at different speeds; the highest speed is typical for the central or axial layer, the lowest - for the near-wall layer, the speed of the axial layer is approximately 2 times higher than the average speed. As a result of the velocity distribution of individual layers, the flow profile acquires a parabolic shape.

At a high flow velocity, after reaching the critical point, the flow loses its laminar character and turns into a turbulent one, at which the parallel character of the movement of individual layers is lost, and eddies appear. Significant energy is expended on their creation, as a result of which, with the turbulent nature of the flow, a direct relationship between its velocity and pressure is lost. The difference in the speed of movement of the individual layers, related to the distance between them, is called the "shear rate". The higher the internal resistance, that is, the viscosity of the fluid, the higher the energy required to overcome it and set the fluid in motion, this force is called "shear stress". Therefore, the ratio of shear stress to shear rate is a measure of fluid viscosity.

All liquids are divided into homogeneous, or Newtonian, and anomalous. Homogeneous liquids are characterized by a constant value of viscosity, which does not depend on shear forces and flow velocity, while the viscosity of anomalous liquids is variable and changes depending on the conditions in which they move.

From a biophysical point of view blood is a heterogeneous multicomponent system of a corpuscular nature, that is, a suspension, a suspension of formed elements in a colloidal solution of proteins, lipids and electrolytes, which is blood plasma. Tissue perfusion is provided by the passage of this concentrated suspension of solid particles through a system of microvessels, the diameter of which in some areas is less than the diameter of the particles themselves. Despite the fact that the specific gravity of blood approaches the specific gravity of water, the rheological properties of blood differ sharply from the latter. This difference manifests itself primarily in the microcirculation system, since in large vessels blood behaves like a homogeneous fluid. In the microcirculatory bed, under conditions where the diameter of the vessel becomes comparable to the size of blood cells, it acquires the properties of a heterogeneous liquid. These properties are most pronounced at the level of capillaries, the diameter of which can even be smaller size shaped elements.

The main manifestation of the properties of blood as a heterogeneous liquid is the dependence of its viscosity on the diameter of the vessel and the rate of blood flow. With an increase in the shear rate or a decrease in the diameter of the vessel in the microcirculation system, the blood viscosity decreases and reaches a minimum value at the entrance to the capillaries, where the shear rate is the highest. On the contrary, with an increase in the diameter of the vessel and a decrease in the shear rate, the viscosity of the blood increases. In this regard, there are macrorheological properties of blood, that is, its properties in the system of large vessels, and microrheological properties in the microcirculation system, a feature of which is a variable viscosity, depending on the nature of the blood flow. Among the most important factors that determine the microrheological properties of blood are hematocrit, the deformability of erythrocytes and their tendency to aggregation, and the structure of the blood flow.

Under physiological conditions, hematocrit is of the greatest importance, there is a direct relationship between its value and viscosity, in the range of hematocrit changes from 20 to 90%, blood viscosity increases 10 times. Blood hematocrit is not a constant value; the concept of "dynamic or local hematocrit" is characteristic of blood microrheology, which can differ significantly from hematocrit in large vessels.

Features of blood movement in microvessels are described by the Foreus-Lindqvist phenomenon, according to which the hematocrit and, accordingly, blood viscosity decrease as the vascular lumen decreases from 300 microns down to the capillaries. So, with a hematocrit value in the central vessels of 50%, the hematocrit in the capillaries of a non-working muscle is only 10%. However, at the level of capillaries, the diameter of which is approximately equal to the size of erythrocytes or even smaller than it, the phenomenon of inversion is noted, the hematocrit increases by 3–5 orders of magnitude, and blood viscosity increases significantly.

Another factor that determines the variability of blood viscosity is the inverse relationship between shear rate (blood flow rate per vessel diameter) and blood viscosity, which means that viscosity increases when blood flow slows down. The relationship between local hematocrit, vessel diameter, and shear rate is determined by fairly complex hydrodynamic mechanisms. During the passage of the blood flow in the microcirculation system, the speed of movement in the axial current is much greater than in the parietal one, due to which a rarefaction is created along the axis, blood cells rush there. Their content in the layers remote from the axis of the vessel is significantly reduced, and the parietal layer turns into a plasma layer. The formation of a parietal plasma current is a consequence of the axial orientation of cells and the separation or separation of blood plasma, the greater the thickness of the plasma layer, the lower the local hematocrit value.

Since the shear rate in the microcirculation system increases as the diameter of the vessel decreases, the thickness of the plasma layer increases in parallel and, therefore, the hematocrit and blood viscosity decrease. However, at the level of capillaries, the vascular lumen is almost completely blocked by formed elements, only a very narrow layer of plasma current remains between them and the capillary wall, which leads to a significant increase in local hematocrit and blood viscosity.

Changes in blood viscosity at different shear rates are also determined by the deformation of erythrocytes. At rest, erythrocytes are round in shape, and when moving at a speed of 6 mm/s, they stretch and take the form of a spindle. This ability depends primarily on the high elasticity of the erythrocyte membrane, and its decrease leads to a decrease in the fluidity of erythrocytes and an increase in blood viscosity.

The relationship between the speed of blood movement and its viscosity is described by the concept of "blood flow structure", which is determined by the distribution and behavior of erythrocytes in the lumen of microvessels. There are 3 types of blood flow structure:

1st type observed under normal conditions at a sufficiently high flow rate. In this case, erythrocytes are oriented along the axis of the vessel, move in parallel layers along the vessel wall, and the velocity profile of individual layers has a parabolic shape with maximum speed at the axis and the minimum - near the wall. Erythrocytes migrate from the walls to the center of the vessel, and a cell-free plasma layer forms near the walls. This blood flow is analogous to the laminar or layered flow of homogeneous fluids.

2nd type of structure is transient and is observed in microvessels with a decrease in blood flow velocity and shear stress. With this type, there is a significant decrease in the velocity gradient of individual layers, the velocity profile deviates from a parabolic shape to a blunt one. This creates conditions for a more chaotic orientation of erythrocytes relative to the axis of the vessel, some of them are located not parallel to it, but almost perpendicular. The trajectory of erythrocyte movement also changes from linear to chaotic, which in combination contributes to an increase in blood viscosity and an increase in blood flow resistance.

3rd type of blood flow structure observed in the smallest microvessels, which approach the size of the lumen to the size of erythrocytes. As a result, each individual erythrocyte occupies almost the entire lumen of the vessel and the blood flow acquires a piston character. Therefore, the viscosity of blood in the capillaries is determined mainly by the deformability of erythrocytes, since in a number of tissues the lumen of the capillaries is smaller than the diameter of the erythrocyte. In order to pass through such a capillary, the erythrocyte stretches in the longitudinal direction and acquires an ellipsoidal shape; in this state, the length of the erythrocyte can exceed its width by 2.2 times. However, even in this case, the erythrocyte occupies only 80% of the lumen of the vessel; the remaining parietal plasma layer prevents the direct interaction of formed elements with the endothelium of the vascular wall.

The deformability of erythrocytes is so great that, with their outer diameter of 7–8 µm, they can pass through a hole 3 µm in diameter without damage. This property of erythrocytes is determined by the special viscoelastic properties of their membrane and the fluidity of the internal contents, due to which, when passing through a narrow opening, the membrane rotates around the cytoplasm, helping to reduce energy loss when overcoming an obstacle and preventing the possibility of blockage of the vessel. Due to this property of erythrocytes, the blood remains fluid even with a hematocrit reaching 98%.

In many different pathological situations - ischemia, diabetes mellitus, stress, inflammation, as well as aging of erythrocytes, the deformability of their membrane decreases, which makes it difficult for them to overcome the capillary network. In this case, erythrocytes can be damaged and release the compounds contained in them in the blood, in particular ADP, which is an activator of platelets and endothelium. All this leads to significant violations of microcirculation. In addition, a decrease in blood viscosity with an increase in blood flow velocity in microvessels is associated with a decrease in the tendency of erythrocytes to aggregate. One of the conditions for maintaining the continuity of the blood flow is the presence in it of separate, unrelated erythrocytes, which can move independently of each other. However, even under normal conditions, when blood flow slows down, aggregation occurs - aggregation of red blood cells. These changes are reversible, when the normal speed of blood movement is restored, the erythrocytes are again separated.

However, under pathological conditions, the aggregation of erythrocytes increases significantly, as a result of which the blood turns into a network suspension with low fluidity. As a result, blood flow can completely stop in combination with blockage of capillaries, the occurrence of stasis in them. The development of stasis is promoted by paralytic expansion of capillaries and slowing of blood flow in them under conditions of ischemia or under the action of inflammatory mediators. Of particular importance for the development of stasis is the thickening of the blood as a result of a parallel increase in the permeability of the capillary wall. Accordingly, the hematocrit increases and the concentration of proteins in the blood, in particular fibrinogen, increases.

Intravascular aggregation of erythrocytes is the cause of "granular current" in the capillaries, for its occurrence, a simple decrease in the rate of blood flow is sufficient. The extreme manifestation of increased intravascular aggregation of erythrocytes is the development of a condition called "sludge", that is, blockage of capillaries by erythrocyte aggregates, which is noted in a number of pathological situations during bulbar microscopy.

Suspension stability of blood and the degree of erythrocyte aggregation are largely a reflection of their functional state, primarily the presence of a negative electric charge on the membrane - the "zeta potential", due to which the electrostatic repulsion of erythrocytes occurs. With a decrease in this charge, conditions are created for increased aggregation of erythrocytes. Of particular importance in this process is the ratio of the content of high- and low-molecular proteins in the blood plasma - albumins and globulins, since albumins help maintain the electrical charge of the erythrocyte membrane, and globulins, primarily fibrinogen, reduce this charge and form bridges between individual erythrocytes, leading to to the formation of their aggregates. At a high shear rate gradient, the formation of erythrocyte aggregates is inhibited and hemodynamic conditions are created for their destruction, while at a low blood flow rate, primarily in venules, erythrocytes converge, thereby creating prerequisites for their aggregation.

RBC aggregation is possible only with the participation of blood plasma, since it requires the presence of fibrinogen, which forms bridges between individual red blood cells. Therefore, the intensity of erythrocyte aggregation is determined not only by their functional state, but also by the concentration of fibrinogen in the blood plasma. Fibrinogen belongs to the proteins of the "acute phase of inflammation" and therefore is one of the most important links that connects inflammation and microcirculation disorders.

The role of fibrinogen in increasing blood viscosity is also determined by the fact that it is the most important factor in platelet aggregation. Under normal conditions, platelets do not take a significant part in determining the characteristics of microcirculation due to their relatively low content in the blood and small particle size. However, the formation of large platelet aggregates may be accompanied by embolization of small capillaries with complete cessation of local tissue perfusion. This mechanism, in particular, is one of the reasons for the development of unstable angina pectoris, when the activation and aggregation of platelets during the destruction of an atheromatous plaque leads to blockage of myocardial capillaries.

The most important integral indicator of the usefulness of microcirculation is the level of functional activity of capillaries, which can be in three states: functioning, plasma and closed. Functioning capillaries contain a flow of whole blood - blood plasma and formed elements, in plasma capillaries with a preserved lumen, only blood plasma is contained, while in closed capillaries there is practically no lumen. With narrowing of the leading arteries, the rate of blood flow in the capillaries decreases, at first they turn into plasma, and then their lumen ceases to be determined. The reason for the presence of these transition states of the capillaries is a change in the local hematocrit in the flowing blood - if the tension of the capillary wall exceeds the fluid pressure in them, the capillaries go into a closed state.

V.V. Bratus, T.V. Talaeva "The circulatory system: principles of organization and regulation of functional activity"

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The microcirculation system is represented by thin vessels less than 100 µm in diameter and is the most resistive part of the vascular bed. The precapillary section consists of arterioles and metaarterioles, in which the ratio of the thickness of the vascular walls to their inner diameter significantly exceeds that of the postcapillary section, which consists of venules. The precapillary section creates 68%, the capillaries - 11.5% and the postcapillary section - 20.5% of the total peripheral vascular resistance.
The blood flow entering the microcirculation system at the level of arterioles is divided into bypass and nutritive. With the help of shunt blood flow, the volume of transorganic blood flow, local and general hydrostatic blood pressure, and the capacity of the vascular bed are regulated. Nutritional blood flow ensures the use of the kinetic energy of the blood to actuate the filtration mechanism for the transport of a fluid containing electrolytes and macromolecules through the interendothelial gaps. This process is regulated by intracapillary hydrostatic blood pressure, colloid osmotic pressure of blood plasma and the degree of contraction of endothelial cells with actomyosin filaments. At the same time, transendothelial exocytosis of some proteins into the interstitium and bilateral transcellular transport of water, electrolytes, and organic molecules are carried out. In the arterial section of the capillaries, 100% of the interstitial fluid enters the interstitium, 90% of it is reabsorbed in the venous part of the capillaries, and 10% is absorbed into the lymphatic vessels. Plasma proteins that penetrate the interstitium return to the bloodstream exclusively through lymphatic system(Drinker's rule).
The microcirculation system provides an optimal level of blood supply to organs and tissues in a different state of their functional activity and energy needs.
At healthy person in a state of physiological rest in organs and tissues, only 1-10% of capillaries function, which provide the optimal volume of blood flow and energy demand. When stimulating and activating the activity of organs and tissues, the number of functioning capillaries usually increases significantly, and by increasing the volume of blood flow, their need for nutrients, oxygen, and the removal of decay products are satisfied.
The regulation of capillary blood flow involves precapillary sphincters, postcapillary venules and arteriovenular anastomoses, which have different sensitivity to vasoactive humoral factors (Table 60).
Table 60. Sensitivity of vessels of the microcirculation system to neurotransmitters and humoral vasoactive factors

Designations: no reaction 0; weak reaction +; average reaction ++; strong reaction +++.
Precapillary muscle sphincters affect the flow of blood into the capillaries by regulating their tone. With an increase in sympathetic influences, the tone of arterioles, terminal arterioles and metaarterioles increases, the tone of precapillary sphincters changes slightly. With suppression of sympathetic influences and an increase in nutritive blood flow, the tone of the precapillary sphincters decreases. Histamine sharply reduces the tone of the precapillary sphincters and promotes the opening of capillaries. The reaction proceeds in two ways: either in the form of a decrease or increase in the number of functioning capillaries without changing the diameter of the arteries that bring blood, or a change in the number and size of endothelial pores. The exchange of substances between the interstitial fluid and the vascular system is carried out in capillaries and postcapillary venules, in which intensive transport of macromolecules occurs. Postcapillary venules regulate the outflow from capillaries by changing their tone. With an increase in the concentration of lactate, histamine, adenosine, bradykinin, a decrease in PO2 and an increase in PCO2, postcapillary venules expand, which facilitates the outflow of blood from the capillaries.
Arteriovenular anastomoses carry out shunt blood flow, participating in general hemodynamic reactions. The tone of the smooth muscles of the anastomoses decreases with the suppression of adrenergic tonic influences. When activated in the tissues of anaerobic glycolysis and the development of irreversible changes in metabolism, the opening of arteriovenular anastomoses potentiates the violation of nutritional blood flow and contributes to the centralization of blood circulation. Damage to the capillaries that carry out nutritional blood flow may be associated with endothelial dysfunction, disintegration of the intercellular substance, loose connective tissue and basement membrane.

Functions of the vascular endothelium

Endotheliocytes regulate vascular tone, blood coagulation, platelet and leukocyte aggregation, release of mediators - prostacyclin, relaxation factor, etc. Endotheliocytes are highly reactive; their synthetic and secretory activity is regulated by thrombin, histamine, bradykinin, blood PO2 level, cytokines, and mechanical factors. Thrombin plays a key role in hemostasis, stimulation of platelet aggregation, in the formation of prostacyclin and protein C activation. Interleukin-1 stimulates the synthesis of prostacyclin, the release of expression factors and thereby regulates fibrinolytic activity and enhances the interaction between neutrophils and other blood cells and endotheliocytes.
in vessels proliferative activity endothelial cells provide physiological angiogenesis. The process of angiogenesis includes the release of enzymes that destroy the basement membrane, the invasion of proliferating endotheliocytes into the surrounding matrix, neoplasm of vessels and the production of the basement membrane - a layer of specialized extracellular substance that separates parenchymal-type cells from the connective tissue stroma. The matrix is ​​constantly updated, as it is destroyed by proteases (metalloproteinases). Physiological angiogenesis consists in the constant formation of capillaries in renewing tissues (reproductive female organs - folliculogenesis in the ovaries, development of the myometrium; in male organs - differentiation of cells in the testicles at various functional states; in mucous membranes - proliferation of epitheliocytes). One of the key regulators of physiological angiogenesis are macrophages that release growth factors (fibroblast growth factor, etc.). In areas of regeneration, physiological angiogenesis is facilitated by an increase in the content of proteoglycans, especially chondroitin sulfate and dextran sulfate.
Pathological angiogenesis is a stimulated new formation of capillaries in areas of damage to organs and tissues, during the formation of the rudiment of a malignant tumor, etc. In pathological angiogenesis, endotheliocytes acquire a pronounced ability for invasive growth due to cell movement and degradation of the extracellular matrix. The growth and mobility of endotheliocytes is combined with a sharp increase in their production of various proteases - collagenase, plasminogen activator, etc., as well as basic and acidic fibroblast growth factors, which are part of the group of heparin-binding growth factors. The direction of growth and migration of endotheliocytes during angiogenesis depend on the state of the extracellular matrix, the formation of epidermal growth factor (in malignant tumors, the growth of epitheliocytes is stimulated by the angiogenesis factor). Angiogenesis underlies wound healing, rheumatic diseases, diabetic angiopathy, etc. When blood vessels are damaged at the beginning of the angiogenesis process, angiogenic stimulants are released - platelet growth factors, fibroblasts, etc. This occurs simultaneously with local degradation of the basement membrane under the influence of collagenase and plasminogen activator, secreted excited endotheliocytes. Stimulation of the proliferation of endothelial cells leads to their migration into the area of ​​the tissue defect. In the area of ​​the ends of the growing capillaries, the division of endothelial cells is activated with the formation of a lumen necessary for connecting individual capillaries, establishing sewerage and resuming blood flow.
The synthetic function of endotheliocytes is aimed at the release of biologically active substances that maintain the liquid state of the blood, smooth muscle tone, the optimal level of lipoprotein metabolism, the synthesis of fatty acids and the inactivation of excess bradykinin, serotonin and prostaglandins. The liquid state of the blood is maintained by the secretion of prostacyclin with a half-life of about 3 minutes, which relaxes vascular smooth muscle and inhibits platelet and erythrocyte aggregation. Along with this, endotheliocytes synthesize and release 13-hydroxy-9,11-hydroxydecadienoic acid, an intracellular factor that prevents platelets from sticking to the surface of the endothelium. Endotheliocytes also secrete a strong vasodilator - nitric oxide. Its release is stimulated by cytokines, acetylcholine, endotheliocyte-dependent vasodilators - adenyl peptides, bradykinin, substance P, ATP, thrombin, serotonin, plasmin, arachidonic acid and other unsaturated fatty acid and an increase in blood flow. Various antioxidants inhibit the formation of nitric oxide - vitamin E and others.
Nitric oxide is transported into cells as part of nitrosothiols. By activating guanylate cyclase and ATP-ribosyltransferase, nitric oxide affects the intracellular content of cAMP and Ca2+ ions. Therefore, nitric oxide is considered a second messenger type of a universal regulator of cellular metabolism in many organs and tissues. In the arterial system, nitric oxide, along with prostacyclin, acts as a smooth muscle relaxant and inhibitor of platelet aggregation and adhesion. The action of nitric oxide on vascular smooth muscle is similar to that of nitrates used in coronary spasms.
Endotheliocytes synthesize and release numerous cytokines into the blood (Table 61).
Cytokines synthesized by vascular endotheliocytes, along with cytokines of monocytes, macrophages, lymphocytes, play an important role in the induction of hemostasis, inflammatory, immune and other pathological processes in the walls. arterial vessels and veins. Endothelial cytokines also regulate hematopoiesis, proliferation and differentiation of T- and B-lymphocytes, and the inclusion of leukocytes in the inflammatory response of blood vessels. An increase in the production of IL-1 and tumor necrosis factor has a pro-inflammatory and prothrombotic effect on the vascular endothelium.
Table 61. Physiological effects of cytokines synthesized by endotheliocytes

These cytokines stimulate the formation of thromboplastin and reduce the content of anticoagulants on the surface of endotheliocytes. They also activate the synthesis of platelet activating factor and the production of plasma plasminogen activator inhibitor, which reduces the breakdown of fibrin clots. Interleukins-1 and 6 activate the synthesis of acute phase proteins in the liver, stimulate T- and B-lymphocytes and other types of cells. Synthesized by endotheliocytes, γ-interferon increases the expression of antigens of the main histocompatibility complex of classes 1 and 2 in cells.
The participation of endotheliocytes in the metabolism of lipoproteins is determined by the content on their surface of the enzyme lipoprotein lipase, an extremely labile factor that is activated during glycosylation. The enzyme is sensitive to changes in the hormonal background, the content of other enzymes in the blood plasma. Lipoprotein lipase provides a cascade of VLDL → LDL LDL reactions and the formation of a subfraction of HDL2 in the bloodstream. With insufficient activity of lipoprotein lipase, the formation of LDL decreases.
Endotheliocytes metabolize ATP and ADP, released by excited platelets and other blood cells, with the help of membrane-bound ATPases, ADPases and 5-nucleotidase to adenosine, which is actively captured by endotheliocytes and utilized by them during metabolic processes.
transport function endothelium is carried out by labile systems, with the participation of which selective and non-selective reabsorption of various nutrients occurs. Adsorptive endocytosis provides selective receptor-dependent transport of certain substrates from the blood. In this way, LDL moves through the endothelium, which in the subendothelial space penetrate into fibroblasts, smooth muscle cells, lymphocytes, where they are cleaved with the participation of lysosomes with the release of cholesterol, a substrate used in the synthesis of the lipid component of cell membranes. Endotheliocytes have the ability to pinocytosis and the formation of micropinocytic vesicles, which ensures the connection of the subendothelial space with blood plasma. By pinocytosis, non-selective reabsorption of substrates contained in the blood plasma occurs. The formation of micropinocytic vesicles increases with an increase in blood temperature and is limited when it decreases. During the induction of micropinocytosis, the surface-bound Ca2+ ions involved in the contraction of endotheliocytes are displaced from the cytoplasmic membrane of cells. Transport of ions, amino acids and other low molecular weight compounds occurs through interendothelial gaps, its intensity is determined mainly by the rate of blood flow in the capillaries and to a lesser extent by the permeability of the capillary membrane. The passage of macromolecular compounds depends on the degree of permeability of the capillary membrane.
The barrier function of the vascular endothelium is determined by the amount of protein substances concentrated on the outer and inner surfaces of endotheliocytes and the structural organization of the subendothelium. On the outer (luminal) surface of the endothelium, the lining is represented by sulfated glycosaminoglycans, which play an important role in the regulation of the permeability of the vascular wall for macromolecules, blood plasma proteins and in ensuring endothelial thrombosis resistance. Glycosaminoglycans located on the surface of the endothelium and in the perivascular space - the matrix, are easily damaged substrates, since they are prone to enzymatic degradation. The subendothelium, including the basement membrane, is a layer of loose connective tissue located between capillaries and parenchymal cells. Subendothelial components are synthesized by endotheliocytes, smooth muscle cells, and fibroblasts. The endothelium has an upper, middle and deep layers, consisting of various ingredients. The upper layer of the subendothelium is synthesized mainly by endotheliocytes. It contains glycoprotein complexes (integrins) involved in the attachment of the inner surface of endotheliocytes to extracellular matrix proteins due to the recognition and binding by receptors of multivalent matrix proteins and fibronectin, collagen or laminin. When the upper layer of the subendothelium is exposed, more active adhesion and aggregation of platelets are induced compared with exposure of the middle and deep layers. The components of the middle and deep layers are synthesized mainly by fibroblasts and smooth muscle cells. These layers contain numerous argentophilic connective tissue fibers embedded in a gel-like ground substance.
In humans, all endothelial functions are regulated exclusively by humoral mechanisms, by changing the local concentration of vasoactive factors - the level of PO2, the concentration of inorganic phosphate, which blocks the ATPase activity of vascular smooth muscle myosin, as well as the content of H+, K+ ions, prostaglandins, histamine, adenosine, etc. Stimulators of contractions of endotheliocytes can be hypoxia, hemodynamic stress, mechanical effects on the vascular wall. At the same time, acetylcholine, epinephrine and norepinephrine, which do not cause contractions of endotheliocytes, are an exception. When exposed to vasoactive substances for several seconds or minutes, endotheliocytes change shape as a result of an increase in the content of Ca2+ ions in the cytolemma: they are rounded, the perinuclear zone protrudes into the lumen of the vessel, folds and outgrowths form. New bundles of microfilaments are formed in the cytoplasm. The contraction of endotheliocytes causes a divergence of interendothelial contacts, the formation of gaps, which sharply reduces the barrier function and promotes the penetration of macromolecules into the subendothelium.
The function of endotheliocytes can be disturbed by various factors. Local damage to the endothelium by mechanical, thermal and other factors already after 50 s leads to the separation of altered cells from the vessel wall and their entry into the bloodstream with subsequent destruction by the macrophage system. The area devoid of endothelium strongly adsorbs platelets and leukocytes from the blood within 10-30 s. Among adherent leukocytes, monocytes predominate and, to a lesser extent, neutrophils. Platelets adsorbed on the subendothelium initially retain a spherical or discoid shape, then they undergo viscous metamorphosis, flatten, form an athrombogenic layer, degranulate with the release of a relatively small number of growth factors and other biologically active products. When platelets close the area of ​​the exposed subendothelium, further adherence of platelets and leukocytes from the blood is sharply reduced. The process of regeneration of the endothelium in the area of ​​the defect begins by activating the proliferation and migration of endotheliocytes in the surrounding areas containing non-altered cells. Initially, viable endotheliocytes at the edges of the defect are firmly attached to the vessel wall and spread out. Then, 8-12 hours after deendothelialization, the migration of individual endotheliocytes begins, which are pulled out parallel to the blood flow. In most endotheliocytes, migration precedes the onset of mitotic division, which is induced 13-24 hours after injury to the endothelial lining and reaches a maximum on days 3-5. 18-20 hours after the injury, migrating and dividing endothelial cells overlay the defect zone at a rate of about 0.5 mm/day. The formation velocity usually exhibits an inverse relationship with the degree of damage to the vessel. In the direction of blood flow, regeneration proceeds faster than in the perpendicular direction. When the continuity of the endothelial layer is restored, the regenerated areas retain increased permeability for a long time. In arteries and veins, the patterns of regeneration of areas with lost endothelium are almost the same.
With indirect and direct effects of pathogenic factors on capillary endotheliocytes, nutritional blood flow is disturbed. This may be due to a decrease in the load on the capillaries as a result of spasm of arterioles and precapillary sphincters, or as a result of a direct damaging effect of altering agents (bacterial endotoxins, antigen-antibody complexes, etc.) on endotheliocytes. Acute ischemia causes damage to capillary endotheliocytes in the form of cell edema, protrusion of the cytolemma into the lumen of the capillaries, and a decrease in the number of pinocytized microvesicles in the cytoplasmic membrane. Such disorders are most pronounced during reperfusion of the vessels of the ischemic focus, when there is a local strong infiltration of capillaries and especially postcapillary venules by leukocytes. Leukocyte infiltration promotes potentiation of capillary damage and increased permeability of microcirculation vessels.
All types of pathogenic effects on blood vessels are characterized by inhibition of proliferation and migration of endotheliocytes to areas with a lost endothelial lining. This contributes to the activation of platelet-vascular hemostasis and the formation of microthrombi. The spread of microthrombosis causes irreversible local damage to the cells of peri-ischemic sites as a result of gross violations of nutritional blood flow. The spread of microthrombosis is prevented by the activation of compensation mechanisms. In the area surrounding the damaged area, mast cells and basophils are irritated, factor XII is activated, vasoactive substances are released - histamine, kinins, prostaglandins, H + ions, etc. This leads to loss of tonic activity of smooth muscle cells of the afferent arterioles, opening of precapillary sphincters and postcapillary venules , expansion of the capillary lumen, an increase in the number of functioning capillaries, an increase in intracapillary hydrostatic pressure and blood flow volume. The rate of filtration of the liquid part of the blood into the interstitial space becomes greater, which leads to an increase in lymph formation and drainage function of the lymphatic vessels, accelerated removal of CO2 and other metabolic products from tissues and organs. In the damaged area, the proliferation of connective tissue elements, capillary endothelium is stimulated, the synthesis of the basic substance is enhanced, and microcirculation is gradually restored.
With large areas of vascular deendothelialization, a large number of platelets, monocytes and neutrophilic leukocytes adhere to the exposed subendothelium, as the formation of a platelet monolayer is disrupted, which prevents additional adsorption of blood cells. During the viscous metamorphosis of numerous platelets, many growth factors and heparinase are released. These substances, together with blood plasma components, penetrate into the middle and deep layers of the vascular subendothelium, which contain smooth muscle cells. 1–4 days after deendothelialization, smooth muscle cells stimulated by mitogens proliferate intensively. Possessing mobility, they migrate through the fenestra of the basement membrane. By the 7th day after deendothelialization, proliferating migrating cells form thickenings that impair vascular function. In the area adjacent to the zone of deendothelialization, the proliferation of endotheliocytes is activated, but most of them continue to be outside the thickenings due to the slow movement of the endothelial layer on them. Gradually, the endothelial layer covers the thickenings and the endothelial lining of the vessel is completely restored, while the proliferation of smooth muscle cells is inhibited and the thickenings gradually regress. Repeated extensive deendothelializations lead to a weakening of regeneration processes.
In chronic hypoxia, the period of adsorption, aggregation and viscous metamorphosis of platelets on the exposed subendothelium is prolonged, the proliferation of smooth muscle elements is enhanced, and the ability to migrate intact endotheliocytes is weakened. This leads to incomplete replacement of lost cells and long-term preservation of increased permeability of vascular areas where endothelial regeneration has occurred.
Thrombocytopenia is usually accompanied by a decrease in the proliferation of endotheliocytes, as they begin to phagocytize platelets in not enough and be deficient in obtaining trophogens with these cells. The latter leads to the development of small-focal deendothelialization, increased vascular permeability and predisposes to the occurrence of their diseases.
Endothelial dysfunction plays an important role in the origin of many types of pathology of organs and tissues - respiratory distress syndrome, sepsis, atherosclerosis, hypertension, coagulopathy, etc.

Microcirculation is the movement of blood through small blood and lymphatic vessels - arterioles, venules, capillaries. If this process is disturbed, tissue malnutrition and congestion occur. For treatment, it is necessary to influence the cause of this condition and use drugs that activate peripheral hemodynamics.

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Causes of microcirculatory disorders

Factors that can lead to impaired blood flow in small vessels include:

• circulatory disorders in larger vascular networks - ischemia, hyperemia (abnormal blood flow) arterial and venous,;
• dehydration (profuse vomiting, diarrhea, taking diuretics, burns);
• excessive dilution of blood infusion therapy, renal failure);
• increased activity of the coagulation system;
• destruction of the walls in inflammatory, atherosclerotic or tumor processes.

Symptoms of pathology

Circulatory disorders can form in any organ, but the most significant lesions occur in the myocardium, brain and renal tissue, as well as in the vasculature of the lower extremities.

A heart

In the heart muscle, the predominant type of microcirculation disorder is ischemia. It leads to a decrease in myocardial contractility. Clinical manifestations -, and. Can lead to fatal complications or the formation of chronic insufficiency.

The first signs of ischemia:

• general weakness;
• poor tolerance for physical activity;
• slight or moderate pain, tingling in the heart area;
• decrease in performance.

With severe ischemia, patients feel severe attacks of pain behind the sternum, which spread to the arm, shoulder blade, neck.

Brain

With acute cessation of nutrition of the brain, a stroke is formed. The gradual overlap of the arteries against the background of atherosclerosis, hypertension, osteochondrosis leads to stagnant processes and swelling of the brain tissue with foci of necrosis. This provokes the development of dyscirculatory encephalopathy with the following symptoms:

• forgetfulness,
• emotional disturbance,
• decreased ability to know
• difficulty coordinating movements
• unsteadiness when walking
• weakness in the limbs.

Cerebral ischemia (impaired microcirculation)

kidneys

Disorders of microcirculation in the renal tissue occur with an acute cessation of blood flow ( acute insufficiency) or due to chronic progressive processes. The latter are much more common and accompany:

• diabetes,
• autoimmune diseases,
• pyelo- or glomerulonephritis.

Acute renal failure

In these diseases, capillary-trophic disorders develop more slowly than in acute ones, their manifestations can be erased: general weakness, headache, frequent urination at night, swelling under the eyes and on the ankles in the morning.

Acute renal failure is accompanied by a sharp drop or cessation of urine output, poisoning of the body with nitrogenous metabolic products. Only with a timely visit to a doctor can the situation be corrected.

lower limbs

Common causes of microcirculatory disorders in the legs are:

• (spasm of arteries, intermittent claudication);
• angiopathy in diabetes.

With thrombosis, tissue malnutrition can occur suddenly. Its sign is a sharp pain, swelling, pallor or cyanosis of the skin. Chronic changes are characterized by a slow increase in these manifestations, a decrease in sensitivity.

With diabetes, patients note constant chilliness of the legs, a feeling of crawling, numbness, loss of reaction to cold and heat, microtrauma. Often, microcirculatory disorders contribute to the development of fungal infections on the feet, ingrown nails, cracked heels and the appearance of long-term non-healing ulcers.

Watch this video about violations of peripheral circulation and microcirculation:

Diagnosis of peripheral blood flow disorders

The following methods are used to detect ischemic disorders (depending on the location of the pathological process):

Cerebrovascular insufficiency occurs due to insufficient blood supply to the brain. Initially, the symptoms do not give out pathology. but acute form, and later chronic lead to extremely sad consequences. Only treatment of the brain at the initial stage makes it possible to avoid disability.

Angioprotectors and preparations with them are prescribed to improve blood vessels, veins and capillaries. The classification divides them into several groups. Best and modern proofreaders microcirculation, venotonics are suitable for eyes, legs with edema.

Dizziness, fainting, loss of consciousness and other adverse symptoms may indicate that venous congestion has appeared in the head, lungs, cervical region (with cervical osteochondrosis), and liver. What are its reasons? How is the treatment going? Why does congestive angiopathy occur?

With circulatory disorders, a transient ischemic attack may occur. Its causes lie mainly in atherosclerotic deposits. The patient needs urgent help and treatment, otherwise the consequences of a transient cerebral attack may be irreversible.

Under microcirculation It is customary to understand a set of interrelated processes, including blood flow in the vessels of the microvasculature and the exchange inextricably linked with it. various substances blood and tissues and lymph formation.

The microcirculatory vascular bed includes terminal arteries (f< 100 мкм), артериолы, метартериолы, капилляры, венулы (рис. 1). Совокупность этих сосудов рассматривают как функциональную единицу сосудистой системы, на уровне которой кровь выполняет свою главную функцию — обслуживание метаболизма клеток.

Rice. 1. Scheme of the microcirculatory vascular bed

Microcirculation includes the movement of blood fluid through blood vessels with a diameter of no more than 2 mm. With the help of this system, the movement of fluid in the interstitial spaces and the movement of lymph in the initial sections of the lymphatic channel are carried out.

Characteristics of microcirculation

• The total number of capillaries in the human body is about 40 billion.
• The total effective exchange surface of capillaries is about 1000 m 2
• The density of capillaries in various organs varies per 1 mm 3 of tissue from 2500-3000 (myocardium, brain, liver, kidneys) to 300-400 / mm 3 in phase units of skeletal muscles, up to 100 / mm 3 in tonic units and less in bone , adipose and connective tissues
• The exchange process in capillaries mainly occurs by two-way diffusion and filtration / reabsorption

The microcirculatory system includes: terminal arterioles, precapillary sphincter, capillary proper, postcapillary venule, venule, small veins, arteriovenular anastomoses.

Rice. Hydrodynamic characteristics of the vascular bed

The exchange of substances through the capillary wall is regulated by filtration, diffusion, absorption and pinocytosis. Oxygen, carbon dioxide, fat-soluble substances easily pass through the capillary wall. Filtration is the process of exiting fluid from the capillary into the intercellular space, and absorption is the reverse flow of fluid from the intercellular space into the capillary. These processes are carried out as a result of the difference in the hydrostatic pressure of blood in the capillary and interstitial fluid, as well as due to changes in the oncotic pressure of blood plasma and interstitial fluid.

At rest, at the arterial end of the capillaries, the hydrostatic pressure of the blood reaches 30-35 mm Hg. Art., and at the venous end is reduced to 10-15 mm Hg. Art. In the interstitial fluid, the hydrostatic pressure is negative and is -10 mm Hg. Art. The difference in hydrostatic pressure between the two sides of the capillary wall promotes the transfer of water from the blood plasma into the interstitial fluid. , created by proteins, in plasma is 25-30 mm Hg. Art. In the interstitial fluid, the protein content is lower and the oncotic pressure is also lower than in the blood plasma. This promotes the movement of fluid from the interstitial space into the lumen of the capillary.

Diffuse mechanism trans capillary exchange is carried out as a result of the difference in the concentrations of substances in the capillary and intercellular fluid. active mechanism exchange is provided by capillary endothelial cells, which, with the help of transport systems in their membranes, carry certain substances and ions. Pinocytic mechanism promotes the transport of large molecules and cell particles through the capillary wall by endo- and exopinocytosis.

The regulation of capillary circulation occurs due to the influence of hormones: vasopressin, norepinephrine, histamine. Vasopressin and norepinephrine lead to narrowing of the lumen of the vessels, and histamine - to expansion. Prostaglandins and leukotrienes have vasodilating properties.

Human capillaries

capillaries are the thinnest vessels with a diameter of 5-7 microns, a length of 0.5-1.1 mm. These vessels lie in the intercellular spaces, in close contact with the cells of the organs and tissues of the body.

The total length of all capillaries of the human body is about 100,000 km, i.e. a thread that could circle the globe three times around the equator. About 40% of the capillaries are active capillaries, i.e. filled with blood. Capillaries open and fill with blood during rhythmic muscle contractions. Capillaries connect arterioles to venules.

Types of capillaries

According to the structure of the endothelial wall All capillaries are conditionally divided into three types:

• continuous wall capillaries("closed"). Their endothelial cells are closely adjacent to each other, leaving no gaps between them. Capillaries of this type are widely represented in smooth and skeletal muscles, myocardium, connective tissue, lungs, and central nervous system. The permeability of these capillaries is quite tightly controlled;
• capillaries with windows(fenestra) or fenestrated capillaries. They are able to pass substances, the diameter of the molecules of which is large enough. Such capillaries are localized in the renal glomeruli and intestinal mucosa;
• discontinuous wall capillaries in which there are gaps between adjacent epithelial cells. Large particles, including blood cells, freely pass through them. Such capillaries are located in the bone marrow, liver, spleen.

Physiological significance of capillaries It consists in the fact that through their walls the exchange of substances between blood and tissues is carried out. The capillary walls are formed by only one layer of endothelial cells, outside of which there is a thin connective tissue basement membrane.

The speed of blood in the capillaries

The rate of blood flow in the capillaries is small and amounts to 0.5-1 mm/s. Thus, each particle of blood is in the capillary for about 1 s. The small thickness of the blood layer (7-8 microns) and its close contact with the cells of organs and tissues, as well as the continuous change of blood in the capillaries, provide the possibility of exchange of substances between blood and tissue (intercellular) fluid.

Rice. Linear, volumetric blood flow velocity and area cross section in various parts of the cardiovascular system (the lowest linear velocity in the capillaries is 0.01-0.05 cm/s; the time for blood to pass through a capillary of medium length (750 μm) is 2.5 s)

In tissues characterized by an intensive metabolism, the number of capillaries per 1 mm 2 of cross section is greater than in tissues in which the metabolism is less intense. So, in the heart there are 2 times more capillaries per 1 mm 2 than in the skeletal muscle. In the gray matter of the brain, where there are many cellular elements, the capillary network is denser than in the white.

There are two types of functioning capillaries:

• some of them form the shortest path between arterioles and venules (main capillaries);
• others are lateral branches from the first - they depart from the arterial end of the main capillaries and flow into their venous end, forming capillary networks.

The volumetric and linear velocity of blood flow in the main capillaries is greater than in the lateral branches. The main capillaries play an important role in the distribution of blood in capillary networks and in other microcirculation phenomena.

Blood flows only in the "on duty" capillaries. Part of the capillaries is switched off from the blood circulation. During the period of intensive activity of organs (for example, during muscle contraction or secretory activity of the glands), when the metabolism in them increases, the number of functioning capillaries increases significantly ( krogh phenomenon).

The regulation of capillary circulation by the nervous system, the influence of physiologically active substances on it - hormones and metabolites - are carried out when they act on arteries and arterioles. Narrowing or expansion of arteries and arterioles changes both the number of functioning capillaries, the distribution of blood in the branching capillary network, and the composition of the blood flowing through the capillaries, i.e. erythrocyte to plasma ratio.

In some parts of the body, for example, in the skin, lungs and kidneys, there are direct connections between arterioles and venules - arteriovenous anastomoses. This is the shortest path between arterioles and venules. Under normal conditions, the anastomoses are closed and the blood passes through the capillary network. If the anastomoses open, then part of the blood can enter the veins, bypassing the capillaries.

Arteriovenous anastomoses play the role of shunts that regulate capillary circulation. An example of this is the change in capillary circulation in the skin with an increase (above 35 °C) or a decrease (below 15 °C) in temperature. environment. Anastomoses in the skin open, and blood flow is established from the arterioles directly into the veins, which plays an important role in the processes of thermoregulation.

The structural and functional unit of blood flow in small vessels is vascular module- a complex of microvessels that is relatively isolated in hemodynamic terms, supplying blood to a certain cell population of an organ. The presence of modules allows you to regulate local blood flow in individual tissue microareas.

The vascular module consists of arterioles, precapillaries, capillaries, postcapillaries, venules, arteriovenular anastomoses, and a lymphatic vessel (Fig. 2).

microcirculation combines the mechanisms of blood flow in small vessels and the exchange of fluid and gases and substances dissolved in it between vessels and tissue fluid, closely related to blood flow.

Rice. 2. Vascular module

The processes of exchange between blood and tissue fluid deserve special consideration. Through the vascular system per day passes 8000-9000 liters of blood. About 20 liters of liquid are filtered through the capillary wall and 18 liters are reabsorbed into the blood. About 2 liters of fluid flows through the lymphatic vessels. The patterns that govern fluid exchange between capillaries and tissue spaces were described by Starling. hydrostatic blood pressure in the capillaries R gk) is the main force aimed at moving fluid from capillaries to tissues. The main force holding the liquid in the capillary bed is oncotic pressure of the plasma in the capillary (R ok). They also play a role hydrostatic pressure (Rgt) And oncotic pressure of tissue fluid (Mouth).

At the arterial end of the capillary R gk is 30-35 mm Hg. Art., and on the venous - 15-20 mm Hg. Art. R ok throughout remains constant and is 25 mm Hg. Art. Thus, at the arterial end of the capillary, the process of filtration is carried out - the exit of fluid, and at the venous end - the reverse process, i.e. fluid reabsorption. Makes certain adjustments to this process Mouth, equal to approximately 4.5 mm Hg. Art., which holds fluid in tissue spaces, as well as a negative value Rgt(minus 3 - minus 9 mm Hg) (Fig. 3).

Therefore, the volume of liquid passing through the capillary wall in 1 minute (V), with a filtration coefficient TO equals

V \u003d [(R gk + P from) - (R gt -R ok)] * K.

At the arterial end of the capillary, V is positive, fluid is filtered into the tissue here, and at the venous end, V is negative and the fluid is reabsorbed into the blood. The transport of electrolytes and low molecular weight substances, such as glucose, is carried out together with water.

Rice. 3. Exchange processes in capillaries

capillaries various bodies differ in their ultrastructure and, consequently, in their ability to pass proteins into the tissue fluid. So, 1 liter of lymph in the liver contains 60 g of protein, in the myocardium - 30 g, in the muscles - 20 g, in the skin - 10 g. The protein that has penetrated into the tissue fluid returns to the blood with lymph.

Thus, a dynamic balance of blood in the vascular system with intercellular fluid is established.

Exchange processes between blood and tissues

The exchange of water, gases and other substances between blood and tissues is carried out through structures called histohematic barriers, due to the processes of diffusion, vesicular transport, filtration, reabsorption, active transport.

Diffusion of substances

One of the most effective mechanisms of this exchange is diffusion. Its driving force is the concentration gradient of a substance between the blood and tissues. The diffusion rate is affected by a number of other factors described by the Fick formula:

where dM/dt- the amount of substance diffusing through the walls of capillaries per unit of time; to is the permeability coefficient of the tissue barrier for a given substance; S- total surface area of ​​diffusion; (C1 - C2) is the concentration gradient of the substance; X is the diffusion distance.

As can be seen from the above formula, the diffusion rate is directly proportional to the surface area through which diffusion occurs, the difference in the concentration of a substance between the intra- and extracapillary medium, and the permeability coefficient of this substance. The diffusion rate is inversely proportional to the distance over which the substance diffuses (the thickness of the capillary wall is approximately 1 µm).

The permeability coefficient is not the same for different substances and depends on the mass of the substance, its solubility in water or in lipids (for more details, see "Transport of substances through cell membranes"). Water easily diffuses through histohematic barriers, water channels (aquaporins), tiny (4-5 nm) pores, interendothelial gaps (see Fig. 1), fenestra and sinusoids in the capillary wall. The type of pathways used for water diffusion depends on the type of capillaries. There is a constant intensive exchange of water between the blood and tissues of the body (tens of liters per hour). At the same time, diffusion does not disturb the water balance between them, since the amount of water that has left the vascular bed by diffusion is equal to the amount that has returned to it in the same time.

An imbalance between these flows will be created only under the action of additional factors leading to a change in permeability, hydrostatic and osmotic pressure gradients. Simultaneously with water, through the same pathways, the diffusion of polar low-molecular substances dissolved in it, mineral ions (Na +, K +, CI -), and other water-soluble substances is carried out. Diffusion flows of these substances are also balanced and therefore, for example, the concentration of mineral substances in the intercellular fluid almost does not differ from their concentration in blood plasma. Substances with large molecular sizes (proteins) cannot pass through water channels and pores. For example, the permeability coefficient for albumin is 10,000 times less than for water. The low permeability of tissue capillaries for proteins is one of the most important factors for their preservation in blood plasma, where their concentration is 5-6 times higher than in the intercellular fluid. At the same time, proteins create a relatively high (about 25 mm Hg) oncotic blood pressure. However, in small amounts, low molecular weight proteins (albumins) exit the blood into the intercellular fluid through the interendothelial spaces, fenestra, sinusoids, and through vesicular transport. Their return to the blood is carried out with the help of lymph.

Vesicular transport of substances

High molecular weight substances cannot move freely through the capillary wall. Their transcapillary exchange is carried out using vesicular transport. This transport occurs with the participation of vesicles (caveolae), which contain the transported substances. Transport vesicles are formed by the endothelial cell membrane, which forms invaginations upon contact with protein or other macromolecules. These invaginations (invaginations) close, then lace up from the membrane, transferring the enclosed substance into the cell. Caveoli can diffuse through the cytoplasm of the cell. Upon contact of the vesicles with the inner side of the membrane, they merge and exocytosis of the contents of the substance outside the cell occurs.

Rice. 4. Vesicles (caveolae) of the endothelial cell of the capillary. The interendohelial fissure is shown by the arrow

Unlike water-soluble substances, fat-soluble substances pass through the capillary wall, diffusing through the entire surface of endothelial membranes, which are formed by double layers of phospholipid molecules. This ensures high speed exchange of fat-soluble substances such as oxygen, carbon dioxide, alcohol, etc.

Filtration and reabsorption

filtering called the exit of water and substances dissolved in it from the capillaries of the microcirculatory bed into the extravascular space, which occurs under the action of forces of positive filtration pressure.

Reabsorption called the return of water and substances dissolved in it into the bloodstream from the extravascular spaces of tissues and body cavities under the action of forces of negative filtration pressure.

Each particle of blood, including molecules of water and substances dissolved in water, is under the action of the forces of hydrostatic blood pressure (Phk), which is numerically equal to the blood pressure in a given section of the vessel. At the beginning of the arterial section of the capillary, this force is about 35 mm Hg. Art. Its action is aimed at displacing blood particles from the vessel. At the same time, oppositely directed forces of colloid osmotic pressure act on the same particles, tending to keep them in the vascular bed. Critical importance in retention in the vascular bed of water, blood proteins and the oncotic pressure force (P onc) created by them, equal to 25 mm Hg, have. Art.

The release of water from the vessels into the tissues is facilitated by the force of oncotic pressure of the interstitial fluid (P omzh), created by the proteins released into it from the blood and numerically equal to 0-5 mm Hg. Art. The force of the hydrostatic pressure of the interstitial fluid (Рgizh), also numerically equal to 0-5 mm Hg, prevents the exit from the vessels of water and substances dissolved in it. Art.

The forces of filtration pressure, which determine the processes of filtration and reabsorption, arise as a result of the interaction of all these forces. However, considering that under normal conditions the pressure forces of the interstitial fluid are practically close to zero or balance each other, the magnitude and direction of the filtration pressure force are determined primarily by the interaction of the forces of hydrostatic and oncotic blood pressure.

The decisive condition for the filtration of a substance through the capillary wall is its molecular weight and the possibility of passing through the pores of the endothelial membrane, interendothelial fissures and the basement membrane of the capillary wall. Blood cells, lipoprotein particles, large protein and other molecules under normal conditions are not filtered through the walls of capillaries of solid mud. They can pass through the walls of fenestrated and sinusoidal capillaries.

Filtration of water and substances dissolved in it from the capillaries occurs at their arterial end (Fig. 5). This is due to the fact that at the beginning of the arterial part of the capillary, the hydrostatic blood pressure is 32-35 mm Hg. Art., and oncotic pressure - about 25 mm rg. Art. In this part, a positive filtration pressure of + 10 mm Hg will be created. Art., under the influence of which the displacement (filtration) of water and minerals dissolved in it into the extravascular intercellular space occurs.

When blood passes through the capillary, a significant part of the blood pressure force is spent on overcoming the resistance to blood flow and in the final (venous) part of the capillary, the hydrostatic pressure decreases to about 15-17 mm Hg. Art. The value of the oncotic blood pressure in the venous part of the capillary remains unchanged (about 25 mm Hg) and may even slightly increase as a result of the release of water and a slight increase in the protein concentration in the blood. The ratio of forces acting on blood particles changes. It is easy to calculate that the filtration pressure in this part of the capillary becomes negative and is about -8 mm Hg. Art. Its action is now aimed at the return (reabsorption) of water from the interstitial space into the blood.

Rice. 5. Schematic representation of the processes of filtration, reabsorption and formation of lymph in the microvasculature

From a comparison of the absolute values ​​of the filtration pressure in the arterial and venous parts of the capillary, it can be seen that a positive filtration pressure of 2 mm Hg. Art. exceeds the negative. This means that the filtration force in the microcirculatory bed of tissues is 2 mm Hg. Art. higher than the reabsorption force. As a result, in a healthy person, about 20 liters of fluid is filtered from the vascular bed into the intercellular space per day, and about 18 liters are reabsorbed back into the vessels, and its difference is 2 liters. These 2 liters of unreabsorbed fluid go to the formation of lymph.

With the development of acute inflammation in tissues, burns, allergic reactions, injuries, the balance of forces of oncotic and hydrostatic pressures of the interstitial fluid can be sharply disturbed. This happens for a number of reasons: the blood flow through the dilated vessels of the inflamed tissue increases, the permeability of the vessels increases under the influence of histamine, arachidopic acid derivatives, and pro-inflammatory cytokips. In the interstitial spaces, the protein content increases due to its greater filtration from the blood and exit from dead cells. The protein is broken down by the action of proteinase enzymes. In the intercellular fluid, oncotic and osmotic pressure, the action of which reduces the reabsorption of fluid into the vascular bed. As a result of its accumulation in the tissues, edema appears, and an increase in tissue hydrostatic pressure in the area of ​​its formation becomes one of the causes of the formation of local pain.

The causes of fluid accumulation in the tissues and the formation of edema may be hypothyroidism, which develops during prolonged fasting or diseases of the liver and nights. As a result, P blood decreases and the value of positive filtration pressure can increase sharply. Tissue swelling may develop with increased blood pressure(hypertension), which is accompanied by an increase in hydrostatic pressure in the capillaries and a positive filtration pressure of the blood.

To estimate the capillary filtration rate, the Starling formula is used:

where V filter is the fluid filtration rate in the microvasculature; k is the filtration coefficient, the value of which depends on the properties of the capillary wall. This coefficient reflects the volume of filtered liquid in 100 g of tissue in 1 min at a filtration pressure of 1 mm Hg. Art.

Lymph is a fluid that forms in the intercellular spaces of tissues and flows into the blood through the lymphatic vessels. The main source of its formation is the liquid part of the blood filtered from the microvasculature. The composition of the lymph also includes proteins, amino acids, glucose, lipids, electrolytes, fragments of destroyed cells, lymphocytes, single monocytes and macrophages. Under normal conditions, the amount of lymph formed per day is equal to the difference between the volumes of filtered and reabsorbed fluid in the microvasculature. Lymphatic formation is not by-product microcirculation, but its integral part. The volume of lymph depends on the ratio of filtration and reabsorption processes. Factors leading to an increase in filtration pressure and accumulation of tissue fluid usually increase lymph formation. In turn, the violation of the lymph flask leads to the development of tissue swelling. In more detail, the formation processes, composition, functions and lymph flow are described in the article "".