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 Chronic arterial hypertension (hypertension) is a very frequent disease, the main symptom of which is an increase in the contractility of mainly small arteries, which leads to a narrowing of their lumen.
This in turn leads to an increase in general blood pressure and a condition known as arterial hypertension. The disease usually develops in the second half of life, but there are cases of hypertension at an earlier age.
Hypertensive disease is chronic, long-term, but there are cases of its more acute course; the latter cases are more rare, but at the same time the most dangerous and are accompanied by very serious consequences. Quite often, the relatively "calm" course of hypertension is interrupted by separate exacerbations (hypertensive crises), which last for a short time, usually several days, when blood pressure suddenly rises to particularly high numbers and is accompanied by various painful manifestations.
The reason for the development of hypertension in its initial stage is usually of a nervous nature. Various repeated or long-term irregularities in the functioning of the nerve centers that regulate total blood pressure within certain relatively low limits (approximately 130-150 mm Hg for the maximum and 70-90 mm for the minimum pressure in an adult) lead to it.
The centers that regulate blood pressure, that is, those who control the tone of the arteries, in turn, are influenced by the centers of higher nervous activity, sensitively reacting to all kinds of stimuli acting on them from the outside world.
Under the influence of various excessive and unfavorable nervous influences and their combinations, unusual abnormal reactions occur from the cerebral cortex, which is in charge of higher nervous activity, with spread to the vascular centers. The latter sometimes come to a state of chronic excitement, which causes prolonged narrowing of the arteries and an increase in blood pressure.
In turn, a long-lasting chronic increase in arterial blood pressure causes various sequential changes in the body, and above all in the walls of the arteries themselves. In this case, the walls of the small arterial tubules are especially affected - the small arteries and arterioles that supply various organs. Vital organs such as the kidneys and the brain are especially often affected by hypertension.
The wall of small arteries is thin; it consists of a layer of flat bordering cells, several circular layers of smooth muscle fibers and a small amount of connective tissue that connects the arteries with the surrounding tissues. The wall of the smallest arteries - arterioles - is even thinner, the number of circular layers of smooth muscle fibers in it does not exceed one or two.
 The main function of small arteries is to contract their muscle wall, as a result of which the lumen of the artery can narrow even before it is completely closed. Prolonged sharp contraction of small arteries is accompanied by damage to their walls. This leads to the penetration of the constituent parts of the blood into the wall of the arteries, as a result of which such a modified wall is saturated with blood proteins, and sometimes even undergoes necrosis and complete destruction. As a result, the lumen of the artery in the places of the affected areas expands, aneurysmal protrusions of the walls of the arteries are formed, which is especially often seen in the small arteries of the brain.
Such dilated small arteries with destroyed walls often rupture, as a result of which hemorrhage occurs in the brain substance. Sometimes hemorrhages are extensive, multiple and lead to a sudden sudden onset of cerebral activity. In these patients, there is a weakening or paralysis of the movements of those muscle groups that were supplied with blood through a damaged and destroyed artery. There is a picture of an acute cerebral stroke, or brain apoplexy. If the patient remains alive, then gradually there is a resorption of the blood poured into the substance of the brain, and its functions are restored to a greater or lesser extent.
Other consequences of the same disease of small arteries appear in some internal organs, especially in the kidneys. Usually, in advanced cases in persons suffering from hypertension, kidney damage occurs to one degree or another; in them, as in the brain, there is a thickening of the walls of small arteries and arterioles. The walls of these vessels are saturated with blood plasma proteins, thicken, and their lumen narrows. Arteries that bring blood to the main functional elements of the kidneys - to the renal glomeruli - are especially often affected. In the latter, there is an allocation (filtration) of the liquid constituents of the blood and their further excretion through the complex system of the urinary tubules.
When the small arteries that bring blood to the glomeruli are empty, this main function is disrupted. Following the death of the glomerulus, the death of all urinary tubules extending from it occurs. Thus, a part of the kidney perishes, and in the case of the death of many of such parts of it, due to the desolation of small arteries, many small parts of the renal tissue also die. The latter collapse, are replaced by scar tissue, the entire kidney atrophies, decreases in volume, and becomes fine-grained.
Such changes in the kidneys are a characteristic sign of hypertension in its later, renal, stage. These changes in the kidneys are slow, chronically sometimes more acute, relatively quickly causing renal failure.
The kidneys cease to secrete in sufficient quantities various nitrogenous metabolic products of protein substances in the body, for example, urea, uric acid, etc. Lingering in the blood, these products often cause a very severe picture of poisoning - the so-called uremia. Therefore, a common cause of death of patients with essential hypertension, along with cerebral hemorrhage, is uremia.
In addition, characteristic of hypertension is also damage to the heart - the heart muscle (myocardium), which, in a state of hypertension, constantly works hard to maintain high blood pressure. The latter in rare cases can reach a maximum of 250-300 mm Hg, and a minimum of 120 mm and above.
Such a long-lasting increased work of the heart muscle leads to its hypertrophy, that is, to an increase in the volume of the heart, due to the thickening of its muscle fibers. If the weight of a normal heart in an adult man is 380-400 g, then with hypertension often the weight of the heart reaches 500-600 g and more. Cardiac hypertrophy is one of the early, very permanent signs of hypertension and belongs to the category of adaptive phenomena (adaptation of the heart to increased stress due to high blood pressure).
Thanks to the successful work of the hypertrophied heart, blood circulation in hypertensive disease occurs for a long time more or less normally, despite the great obstacle to the work of the heart from the narrowed small arteries. However, over time, the work of such a hypertrophied heart often becomes insufficient to maintain normal blood supply.As a result, blood stagnation occurs in the internal organs, an accumulation of fluid in the body cavities and in the subcutaneous tissue develops - ascites - in a word, a formidable picture of cardiac and circulatory insufficiency arises, which requires urgent measures.
The unfavorable consequences of hypertension are observed especially in those cases when arterial disease with atherosclerosis joins it. The combination of these two diseases is quite common and leads to dangerous consequences, especially if atherosclerosis, leading to a narrowing of the lumen of the arteries, develops, as is often the case, in the system of the coronary arteries of the heart.
Thus, hypertension, which is based on a violation of nervous activity, leads consistently to severe changes in the arteries, and then in the organs supplied by them.
Particularly important in the course of hypertension is the degree of kidney damage. Atrophied (wrinkled) kidneys, penetrated by many small scars, losing their ability to excrete urine, retain the ability to release substances into the blood that have the property of narrowing small arteries and maintaining blood pressure at a high level.
Great successes in the prevention and treatment of hypertension make it possible to prolong the life of such patients for a very long time. As a preventive measure, it is necessary to recommend a regime that spares the nervous system, that is, ensures the correct alternation of work and the sufficiency of rest, allowing you to avoid any stress and breakdowns of nervous activity.
Further, it is especially important to avoid the consumption of all those substances that put a great strain on kidney function (large amounts of meat, spices, wine, tobacco). It is also necessary to avoid the development of atherosclerosis, so often aggravating the course of hypertension, to apply all the methods of prevention and treatment that are mentioned above when describing this disease.
Of the currently used drugs, one can point to a number of substances that cause a decrease in blood pressure and help to improve the condition of patients suffering from hypertension. However, the use of these substances is possible only on the prescription of the attending physician - therapist.
N. N. Anichkov - Diseases of the arteries
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