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PorPsyko  - 
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Heart work without an understudy # 002

Hence the "Starling's law" appeared the more the heart muscle is stretched, the stronger the contraction.The quality is somewhat mechanical: if you want to send the stone farther from the slingshot, you need to pull back the rubber band harder.Although the mechanism here is completely different.In the laboratory of Kositsky, special equipment was invented.She allowed me to measure the pressure in the "dry heart".The cat's heart was forced to idle.A heated solution, artificial blood saturated with oxygen, was passed through the coronary vessels (through which the muscles receive nutrition).And into the atria and ventricles, thin rubber bags filled with liquid were introduced through the cut vessels.The more fluids were injected, the more the atrium or ventricle stretched.The heart was beating - the liquid was expelled from the bag into the manometer tube.The stronger the contraction, the higher the liquid rose through the tube.Strongly stretched the balloon in the right atrium - the pressure in the ventricles immediately jumped.And between them there was no connection - even the blood did not pass!What is the Starling effect, the law of the rubber bag?But this law is valid for one camera.

Only the atrium itself should respond to stretching.This is exactly how the ventricles behave.They don't signal anyone.And the atria seem to warn: get ready, there is a big load!Excellent proof of the existence of independent nerve nodes!A pressure sensor hidden in the wall of the atrium sent a signal to the center, but not a general one, located somewhere in the spinal cord, but its own, heart.The signal was received, recorded, and converted into an order directed to the ventricle.He immediately intensified his activities.It is quite logical that the increase in pressure in the ventricle has no effect on other parts of the heart.After all, blood from the ventricle is pushed out of its limits.The Starling effect is enough here, when a team (also not without the participation of nerves!) Appears and is implemented in the same department.Then why has nature "connected" the heart nodes to the center, if the heart has such a system of self-government?First of all, because the heart must be subject to orders from the center, which coordinates all the work of the body.The intracardiac nerve nodes, says Kositsky, are ready-made control units.They record the behavior of the heart for all occasions.And there is absolutely no need for the central nervous system to transmit details such as pulse rate, degree of filling, and so on through long wires.Firstly, distortions are possible during transmission, and secondly, why do calculations “at the highest level” every time?In addition, a complete loss of communication is possible.The disease spares neither the brain nor the spinal cord.It can do the same thing as a surgeon's scalpel.Of course, nature was not guided by these considerations, creating such a reliable system of heart control.It was easier.Apparently, at first, in the most ancient organisms, the heart was a simple muscular sac with valves and worked like a rubber one - the more blood was supplied, the more was thrown away.Then the mechanism of intracardiac regulation appeared - nerve nodes with ready-made programs.Such a heart is already more adapted to variable activity.And only at the last stage, in the most highly developed animals, does it obey the common center.The reliability developed by millions of years of struggle for existence was backed up by precision and speed.