What causes the heart rate to change? Detailed answer

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What causes the heart rate to change? Detailed answer

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What causes the heart rate to change?

Each of the human heart beats lasts approximately 0,8 seconds. During the day, it makes about 100 strokes, resting after each equal interval of time. For a year, somewhere around 000 strokes are obtained. The beating of the heart is the rhythmic contraction of the heart muscle, causing blood to circulate throughout the body. Therefore, the heart rate (and pulse beats) depends on the body's need for blood supply.

A change in the heart rate can most often be observed during heavy physical work. Here's how it goes. During the work of the muscles of our body, carbon dioxide is formed. Its molecules are transported by blood within 10 seconds to one of the four chambers of the heart, called the right atrium, which contains cells that respond to the presence of this acid. They adjust the heart rate to the amount of carbon dioxide in the blood. When the muscles of the body stop working, the amount of carbon dioxide in the blood decreases, and, accordingly, the heart beats more slowly.

The activity of the heart is connected with the needs of our whole organism. Mental excitement stimulates the nervous system, and this also makes our heart beat faster. When we are depressed or fearful, other nerves are stimulated, which causes the heart to beat more slowly.

An ordinary person cannot cause a rapid heartbeat simply by an effort of will, but there were people who had the ability to do this. One person could even make the heart stop and “freeze”, so that those around them began to think that he was really dead. But then he made his heart beat like before again.

Author: Likum A.

Random interesting fact from the Great Encyclopedia:

What is the first space velocity?

The first cosmic speed is the minimum speed that must be reported to any physical body (for example, a spacecraft) located in the gravitational field of a celestial object (for example, a planet or a star) in order for this body to become a satellite of a celestial object.

On the surface of the Earth (at sea level), the first cosmic velocity is 7,91 kilometers per second (in this case, the Earth is considered to be absolutely smooth and devoid of an atmosphere). With increasing distance from the attracting object, the first escape velocity decreases. So, at an altitude of 300 kilometers above the Earth's surface (sea level), the first cosmic velocity is 7,73 kilometers per second, at an altitude of 1000 kilometers - 4,94 kilometers per second.

The first cosmic velocity on the surface of the Moon is 1,68 kilometers per second.

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Revealed the secret of dog friendliness 27.07.2017

Scientists from Oregon and Princeton jointly figured out the genetic basis of the friendliness of domestic dogs.

At the first stage, the authors compared the behavior of 18 different domestic dogs - both purebred and half-breeds - and 10 wolves living in captivity and raised by people in close contact with them (in one of the research institutes located in Indiana, USA). It turned out that dogs are much friendlier than wolves, even "domestic" ones.

After that, Udell and von Holdt turned their attention to people with Williams syndrome - a hereditary disease that is expressed in an "elven" face and partial mental retardation, but with increased friendliness and sociability. This is caused by a deletion (disappearance) of a section of the 7th chromosome, and the more changes there are, the more pronounced this syndrome is in humans.

Genetic analysis showed that in dogs there is a similar mechanism, only not in the 7th, but in the 6th chromosome. There, the corresponding site is responsible for the production of the GIF21 protein, which, in turn, regulates the activity of some other genes.

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This study is important because although we have learned a lot about dogs recently - for example, that they are able to perceive speech and have episodic memory - the genetic basis of these abilities is still largely unexplored. Meanwhile, it can have important consequences, including applied ones.

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