Thursday, August 9, 2018

The Miracle of Muscle: By J.D.RATCLIFF


Courtesy: Medical Miracles, from Readers Digest 1981. November.
From the frontiers of science and the far horizons of personal courage, these stories of medical triumphs and miracles will reaffirm your faith in the awesome powers of the human spirit. Dramatic victories and human triumphs.
Selected and edited by the editors of Readers Digest
Events that take place when a dog wags its tail, a baby toddles across the floor or you scratch your nose with your forefinger dwarf in complexity the workings of a hydrogen bomb.  All are examples of muscular contraction—so commonplace we pay it no heed, yet so mysterious that it has baffled the most gifted scientists.
More than half of the human body is muscle—“the most remarkable stuff in nature’s curiosity shop,” as one scientist had said.  From birth to death, muscles play a critical role in everything we do.  They propel us into the world in the first place—when the womb suddenly empties itself.  They provide nearly all our internal heat.  They push food along the digestive tract, suck air into lungs, and squeeze tears from lachrymal glands.  And finis is written for fails and us when the heart muscle, after beating two and half billion times in a 70-year life span, flatters.
We speak of “muscles of iron.”  Yet the working or contractile element in muscle is a soft jelly.  How this jelly contracts to lift 1000 times its own weight is one of the supreme miracles of the universe.  An elaborate series of chemical and electrical events, which would require hours of days to duplicate in the laboratory, occurs almost instantaneously when a muscle contract—the twitch of an eyelids, for example.
There are three types of muscle in the human body.  One is the striated muscle, which looks like a sheaf of hair-sized filaments.  These are the muscles of motion—that propel us when we walk, that lift a forkful of food, that nod our heads.  Next come the “smooth” muscles.  These control such involuntary actions as the churning of intestines during digestion, the dilation of the pupil.  A third type is found in the heart.  In structure, it is midway between the other two.  All types of muscle are startlingly efficient machines for converting chemical energy [food] into mechanical energy [work]. 
Hundreds of books and scientific papers have been written on muscles—but none explains fully the process by which muscles contract, how you wiggle a tow.  “It is essential that we understand these puzzles,” said Dr. Albert Szent-Gyorgyi, Nobel Prize winner and scientific director of the National Faundation for Cancer Research.  “In one was or another, failure of muscles to contract porperly accounts for the vast majority of deaths—from heart failure, high blood pressure and other diseases.”
It is the riddles such as these that Dr. Szent-Gyorgyi and his co-workers went years seeking to solve.  Fiber by fiber and molecule by molecule they have taken muscles apart, and then fitted them together again trying to discover the mechanics of muscular action.
Research suggests that muscle is never thoroughly relaxed.  Because it is partially tensed—something like a taut spring—it is ready for almost instantaneous action when an electrical message from the brain orders it to contract.
Twp proteins, Dr. Szent-Gyorgye has found, are mainly responsible for the contraction—actin and myosin.  Alone, neither is contractile.  But when an electrical impulse from the brain orders the batting of an eye, or the wrinkling of a nose, actin and myosin combine to form actomyosin, which is contractile.
In a sense of actomyosin is the muscular ‘engine.’  Its fuel is a remarkable chemical substance, adenosine triphosphate—ATP for short.  ATP is a submicroscopic bombshell of energy.  Actomyosin fibers contract violently on contact with it.  At death, ATP disintegrates rapidly and muscles become hard, inelastic.  This is rigor mortis.
To demonstrate the critical importance of ATP, Dr. Szent Gyorgyi stored rabbit muscles, which had been washed free of the chemical, in freezers for periods up to a year.  Taken out, thawed and touched with ATP, the hard, brittle muscles spring to life; once again they show the elasticity they had when they propelled a rabbit in its hopping gait.
Creating ‘living’ tissue in the laboratory has been something of a scientific will-o-the-wisp.  But muscle researchers have come close to it.  Dr. Szent-Gyorgyi mixed jelly-like actin with jelly-like myosin.  Then, with the aid of a tiny glass nozzle, he spun this material into gossamer filaments.  Watching through a microscope, he added a droplet of ATP to the fluid surrounding the filament.  There was violent contraction!  He had created artificially perhaps the most fundamental of all life processes—muscular contraction.  “It was, “he says, “the most exciting moment of my life.”
Where are such experiments leading?  They may open a new frontier of attack on some of mankind’s greatest ills.  There is no logical reason why the human heart should beat two billions times during a lifetime, the suddenly fail.  Almost nothing is known about the cruel crippling of muscular dystrophy; or why muscles in blood-vessel walls should tighten to produce the misery of hypertension; of why the uterine muscles of many women become crumply contracted each month to cause painful distress.  Once the mechanics of muscular action are thoroughly understood, we may be at the beginning of a new biology, a new medicine.
Meanwhile, there is a great deal all of us can do to keep our muscles functioning well.  First, they must be promptly fed.  Generally speaking, the average diet includes all the protein needed for muscle repair, and all the carbohydrate required for muscle fuel.  But muscles can starve through lack of exercise—witness hospital patients who eat perfectly balanced meals and get out of the bed too weak to walk.  Reason: muscles are nourished by thousands of miles of hairline capillaries, which transport food and carry off wastes.  In the sedentary adult, large numbers of these capillaries are collapsed, out of business, nearly all the time.  Exercise alone can open them up and provide better muscle nutrition.
A number of studies have shown the beneficial results of exercise on the heart muscle.  A study in London bus drivers, for example, showed that drivers, who sat all day, had far more heart trouble than conductors, who were constantly on the move.  Similar checks have shown office workers more prone to heart disease than postal workers.
Often, muscles become unduly fatigued when required to work at too fast a rate.  One housewife rushes at her chores and is worn out by noon, while her more leisurely sister accomplishes just as much and finishes the day still fresh.  A series of treadmill experiments tells why.  In one, subjects were paced at 140 steps a minute.  Gradually speed was increased to 280.  At the doubled rate, oxygen requirements of muscles increased eightfold supplying such demands are fatiguing in it.  All work and exercise should be paced to get the most of our muscles.
Like all other body organs and tissues, muscles must have rest.  Millions of people sleep the traditional eight hours, and then get up exhausted.  The most likely explanation: one set of muscles has been cramped, tensed all night—wearing out the rest of the body.  The best way to avoid this is to become acquainted with your own muscles.
Lie quietly in bed, legs straight, and arms at the side.  Contract one set of muscles at a time, and consciously relax them.  Start with the feet and work upward.  In a matter of minutes, real relaxation can be achieved—leading to more restful sleep.
Overburdened or weakened muscles sometimes require additional support.  This is particularly true of the back muscles, whose chief function is to hold the body erect.  Often, low-back pain can be traced to weakness of these muscles. Every physician has his favorite set of exercises to provide new strength.  But until exercises are well under way, extra support is sometimes necessary.  A strong extra-wide belt is useful for this purpose.
It is best, of course, not to wait until muscles are weakened before giving them the care and consideration they deserve.  For, to a great degree, we are what our muscles make us—sick or well, vigorous or droopy, alive or dead.

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