What is blood pressure? Detailed answer

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What is blood pressure? Detailed answer

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What is blood pressure?

Many older people have high blood pressure. It is generally accepted that 15-20 percent of the deaths of older people over fifty in the US are due to high blood pressure! What is blood pressure? This is the pressure exerted on the blood by the heart and arteries. When the left ventricle of the heart contracts, it pushes blood into the arteries. The main arteries must dilate to allow this blood to pass through.

But the muscular lining of the arteries resists this pressure, and the blood is forced out into the body's smaller blood vessels. Therefore, blood pressure is the level of blood pressure that appears as a result of the work of the heart and the resistance of the walls of the arteries.

There are ways to measure blood pressure, and a certain pressure value is considered normal for a certain age of a person. But in some people, this pressure begins to exceed normal, and this phenomenon is called hypertension, that is, high blood pressure. This can happen for many reasons, such as nervous tension or malfunction of the endocrine glands or kidneys. It is usually difficult to find out all the reasons. And in most cases, the pressure can be elevated without any unpleasant symptoms.

In other cases, the condition deteriorates rapidly. What happens is that the small blood vessels of the circulatory system resist the flow of blood. Then certain symptoms may appear. Palpitations, headache, dizziness, and a feeling of tiredness may occur.

Medicine has numerous remedies for the treatment of such a condition, depending on the specific case. These remedies include rest, changing activities, a weight-reducing diet, a low-salt diet, surgery, and so on.

Author: Likum A.

Random interesting fact from the Great Encyclopedia:

What are physical binary stars and how are they distinguished by the way they are observed?

Until the XNUMXth century, it was believed that the duality of the stars is a consequence of their completely random arrangement, in which, although they are visible one close to the other, they are far from each other in space. However, at the beginning of the XNUMXth century, the English astronomer William Herschel discovered that some double stars are physically connected pairs. Such binary stars began to be called physical binaries (in contrast to optical binaries, which are not physically connected).

A physical binary star is a pair of stars that are close enough to each other in space and, obeying the law of universal gravitation, rotate around a common center of mass. Physical binaries are divided into three main classes: visual binaries, spectroscopic binaries, and eclipsing binaries.

This classification reflects not the essential difference between binary stars, but the ways in which they are defined (separated by their components). Visual binaries include all binary stars that can be directly separated into components (at least with the help of large telescopes).

Currently, more than 70 thousand visual double stars have been cataloged. Spectral binary stars cannot be seen separately using modern optical means. But their duality is revealed by periodic changes in their spectrum - shifts or separations of spectral lines. If both components of a binary star have the same brightness, and especially if they belong to the same spectral class, then the periodic bifurcation of the lines and their merging are especially clear. If the lines of the spectrum of only one component are visible, then they periodically oscillate around a certain average position.

The Doppler principle gives an exhaustive explanation for this: the shift and bifurcation of the lines occurs due to the orbital motion of the components around a common center of mass, and the plane of the orbit does not make a very large angle with the line of sight.

Currently, about 2500 spectroscopic binary stars are known. Eclipsing binaries are those stars in which the plane of the orbit of their components makes a sufficiently small angle with the observer's line of sight, as a result of which one star can completely or partially obscure the other for a while. More than 4000 eclipsing binary stars have already been discovered.

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LM46002 - 60V low current DC-DC regulator from TI 23.12.2014

New chips LM46000, LM46001, LM46002 from Texas Instruments expand the line of the 6th generation DC/DC converters of the Simple Switcher family. To date, the new line includes seven microcircuits: LM46000, LM46001, LM46002 with input voltage up to 60 V and LM43600, LM43601, LM43602, LM43603 with input voltage up to 36 V.

All microcircuits of the 6th generation are synchronous converters with high efficiency in the entire range of current loads and low current consumption, both in operation and in standby mode. High efficiency and low current consumption make it possible to exclude the use of an additional LDO parallel regulator with low own consumption in systems where it is necessary to provide output voltage in a wide range of current loads, including in standby mode.

With a maximum input voltage of 60V for the LM4600x, it can be used in a variety of automotive and industrial applications, providing additional transient protection. In addition to a wide input voltage range, the LM4600x can be configured with a switching frequency ranging from 200 kHz to 2.2 MHz, which helps to optimize the solution even for smaller components.

Additionally, it is worth noting the improved TSSOP package, which, in addition to the convenience of prototyping and production, provides pin compatibility between all microcircuits of the family: LM46000, LM46001, LM46002, LM43603, LM43602, LM43601. This compatibility allows you to use the same PCB design for all chips of the family and implement solutions with maximum output currents from 500 mA to 3 A at input voltages from 36 V to 60 V with minor adjustments to the values of external components in one form factor. Optimized external pinouts and integrated high and low side key transistors reduce the number of external components while achieving increased efficiency, smaller board area, and better EMI compatibility.

Separately, it is worth noting the possibility of simplifying the design of a printed circuit board thanks to the Webench service available on the manufacturer's website, which allows you to export a printed circuit board design that meets all the necessary requirements for EMI and temperature conditions in a CAD program. For those who want to test chips in real conditions, TI offers ready-made development boards LM46002PWPEVM.

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