Page 90 - The Miracle of Electricity in the Body
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88                 THE MIRACLE OF ELECTRICITY IN THE BODY





                   In cases where the heart cannot make this adjustment, an electronic
              pacemaker is used to adjust the speed of the heartbeat. However, these
              artificial devices bring with them a number of drawbacks that require
              careful attention. They must not enter magnetic fields, and have to be
              kept away from devices that generate magnetic fields. Yet no such prob-
              lems are experienced in the heart’s natural pacemaker. How, then, did a
              group of cells in our bodies determine—and then meet—needs of which
              we are consciously unaware? This is a precautionary measure in our
              bodies, a comfort prepared for us beforehand. All this is just one of the
              signs of the infinite mercy of our Lord.

                   There is no one in the heavens and Earth who will not come to the
                   All-Merciful as a servant. He has counted them and numbered them
                   precisely. (Surah Maryam, 93-94)



                   The Accelerator-Brake System in
                   the Heart’s Operations
                   Most people know that their hearts speed up under certain circum-
              stances—as when they quickly climb a staircase, run or become excited.
              The heartbeat speeds up, returning to its normal rhythm later. However,
              most people fail to realize what a great miracle this actually is. The speed
              of the heartbeat is regulated by a natural computer system installed in-
              side the body.
                   When heartbeat accelerates, unless the body is provided with suffi-
              cient oxygen, the cells lose their electrical equilibrium and begin beating
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              fast and irregularly. For that reason, it is of the highest importance that
              the heart should beat constantly at a regular rhythm. Like a car traveling
              at a fixed speed, the heart’s tempo also needs to be speeded or slowed in
              certain situations. The “brake pedal” that slows the heart’s rhythm is the
              vagus nerves, and the throttle that speeds it up is the sympathetic
                      58
              nerves.* A messenger molecule called acetylcholine permits the brak-
              ing action.
                   The heart normally beats 72 times a minute. In situations that place
              a strain on the heart, when a person is under stress or running a fever,


              *Sympathetic nerves: components of the autonomous nervous system that work outside our
              conscious control and regulate the workings of the internal organs.
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