Blood pressure is the pressure in the blood vessels. Without it, the full implementation of metabolic processes in the tissues of the body is impossible. Thanks to him, blood moves through the circulatory system.
Blood pressure is created inside the arteries, capillary, respectively, inside the capillaries and venous in the veins.
In addition, there is an osmotic pressure of the blood, it depends on the concentration of mineral salts in it. Its value usually remains stable. But even a minimal change can destroy blood cells. Sweat glands and kidneys are responsible for the neurohumoral regulation of osmotic pressure.
The magnitude of arterial blood pressure will be affected by:
- the power of heart contractions;
- the amount of blood ejected by him at a time with each successive reduction;
- the resistance that the walls of blood vessels (peripheral) exert to a moving blood stream;
- the number of contractions of the heart for one accepted unit of time.
Secondary factors affecting blood pressure are its quantity and viscosity. And also this is the difference in pressure in the abdominal cavity and in the chest cavity, which occurs in connection with movements during breathing.
The maximum blood pressure happens when the left ventricle of the heart (systole) contracts. In this case, approximately 70 ml of blood is expelled from it at a time. Through the capillaries and other small vessels, such an amount can not immediately pass. The aorta, due to its elasticity, is stretched, while systolic pressure also rises in it. In a person (healthy) over 16 years of age, it can range from 110 to 130 mm Hg. Art.
During diastole - a pause between two contractions of the left and right ventricles - the stretched walls of the large arteries and aorta begin to contract. Thus, they push blood into the capillaries. Its pressure drops and at the end of the diastole in the aorta drops to 90 mm Hg. Art., and in large arteries - up to 70 mm RT. Art. The difference between the indicators of systole and diastole is perceived by a person in the form of a pulse.
The greater the distance from the blood vessels to the heart, the lower the pressure in them. The first, upper digit indicates systolic pressure, and the second, lower, indicates diastolic pressure.
In large arteries it is higher, in arterioles less. Upon transition to the capillary bed, blood pressure decreases, in the venous even more drops, and in the vena cava it reaches even negative values.
Measuring it in veins or capillaries is technically not very simple. Therefore, the magnitude of the pressure is judged on the basis of its definition in the arteries.
Its indicators normally depend on how a person lives, what he does, what individual characteristics have. With age, the pressure changes. It also increases with increased emotional stress, physical work. And at the same time, among athletes, people who constantly and hard work physically, it can even decrease.
Systolic pressure in children is determined by the formula 80 + 2a, in which a is the age (number of years).
The mechanisms that exist in the body and control the level of pressure allow you to return it to normal after slight fluctuations as a result of emotional stress or physical labor.
If they are violated, there is a persistent change in the direction of increase, then they talk about arterial hypertension, or downward, then we are talking about arterial hypotension.
Usually, anyone knows their blood pressure. And any deviation in one direction or another should serve as a reason for going to the doctor, because there are many reasons that affect this indicator. For example, with infectious, cardiac diseases, with poisoning, hypotension often occurs. And with kidney diseases, endocrine disorders - hypertension.