The Body: A Living Dynamo, Part 1

You may not believe it, but we are a living dynamo – a human battery.

Executive Fitness Newsletter reports that the use of electricity in controlling pain, the healing of broken bones, and the treatment of body disorders with acupuncture needles, has been well-known. Yet, most of us still consider electricity alien to the human body; on the contrary, electricity is a basic constituent of every living cell.

In explaining that electricity may replace drugs as the prevailing therapy, British Neurophysicist Dr. W. Grey Walter, compares the human brain to a computer; that it would take at least 10 billion electronic cells, occupying some million and a half cubic feet, to duplicate the brain. The system would require one billion watts of power.

Even heart action in its every beat, is the result of muscle contraction caused by electrical impulses. But it is the nervous system that most graphically illustrates the intricate part electrical energy plays in the various functions of the human body.

As the body’s communication system, the nerves are constantly carrying messages throughout the body. Any stimulus – heat, light, sound or whatever it is – acts upon the nerve cell (neuron) to fire an impulse which is transmitted along the nerve fiber (axon).

Electric currents travel along copper wire at a little less than 186,000 miles a second, the speed of light. But impulses traveling through long nerve fibers move at the rate of only 350 feet a second, or 250 miles per hour. The speed is reduced in some shorter fibers to about 2.5 miles per hour.

Copper, the most common type of electric wire, is such a good conductor that most of the electrical energy arrives at the other end. But in the case of axons, energy leaks out so badly that if it were not for the constant amplification all along the way, energy would never reach the end.

There are two types of neurons: sensory nerves that transmit sensations, and motor nerves that send orders. It is the sensory nerves that send out a hurried S.O.S. to the brain when you touch something hot. And it is the motor nerves that race back the signal to move your finger.

Sensory messages, or impulses, travel from billions of neurons to the brain and spinal cord every second. Neurons do not respond to stimuli below a certain threshold – particles of air and fine dust are ignored – and the stimuli above the threshold receive an impulse of a fixed intensity. What is believed to cause different responses to different stimuli is the number of neurons that are activated to form a pattern or code.

Researchers believe nerve cells are fired by the passing of ions across the cell’s membranes. Ions are electrified particles formed when an atom loses or gains electrons. They are contained in every molecule of matter.

(Part 2 will be posted next Monday, Dec. 19, 2011. – J.P.)