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In these challenging days when the forces of evolution would have it that we are the products of an accident, let us remember and frequently meditate upon the incredible complexities of the human body. 15.5 billion years would never be enough time to accidentally result in what will be presented in these meditations. Maybe in 100 trillion years there would be the beginnings of some organization. Statistically, what will be presented is an absolute impossibility for evolution to bring about. Rather this wonderful creation of man can only be the result of a God with infinite Wisdom, Ability, and Beauty! Not only did He create all of the heavens in 5 days, but he created man in one day and never did He make a mistake. To His honor these meditations are presented.
A pipeline exists inside each one of us, servicing 100 trillion cells in the human body. An endless supply of oxygen, amino acids, nitrogen, sodium, potassium, calcium, magnesium, sugars, lipids, cholesterols, and hormones surges past our cells, carried on blood cell rafts or suspended in the fluid. Each cell has special withdrawal privileges to gather the resources needed to fuel a tiny engine for its complex chemical reactions.
This same pipeline ferries away refuse, exhaust gases, and worn-out chemicals. In the interest of economical transport, the body dissolves its vital substances into a liquid. Five or six quarts of this all purpose fluid suffice for the body's 100 trillion cells.
When blood spills, it appears as a uniform, syrupy substance ranging in color from bright red to dark purple....A simple experiment confirms the composite nature of blood. Pour a quantity of red blood into any clear glass and simply wait. Horizontal bands of color will appear as various cells settle by weight, until the final multi-layered result resembles an exotic cocktail. The deepest reds, comprising clumps of red cells, sink to the bottom; plasma, a thin yellow fluid, fills the top part of the flask; platelets and white cells congregate in the pale gray band in between.
The microscope unveils the staggering reality of a drop of blood. A speck of blood of the size of the letter "o" contains 5,000,000 red cells, 300,000 platelets and 7,000 white cells. The fluid is actually an ocean stocked with living matter. Red cells alone, if removed from a single person and laid side by side, would carpet an area of 3,500 square yards.
The body's survival depends on the cells with a delicate flower-like shape, the platelets. Science now recognize that platelets, which circulate only 6 to 12 days in the blood, play a critical role in the life-saving process of clotting; they serve as a mobile first-aid boxes by detecting leaks, plugging them, and tidying up the debris.
When a blood vessel is cut the fluid that sustains life begins to leak away. In response, tiny platelets melt, like snowflakes, spinning out a gossamer web of fibrinogen. Red blood cells collect in this web, like autos crashing into each other when the road is blocked. Soon the tenuous wall of the red cells thickens enough to stanch the flow of blood. Platelets have a very small margin of error. Any clot that extends beyond the vessel wall and threatens to obstruct the vessel itself will stop the flow of blood through the vessel and perhaps lead to a stroke or coronary thrombosis and possibly death. On the other hand, people whose blood has no ability to clot live short lives. The body cannily gauges when a clot is large enough to stop the loss of blood but not so large as to impede the flow within the vessel itself.
- excerpt is taken from In His Image by Philip Yancey and Dr. Brand, pgs 55-6
Sixty thousand miles of blood vessels link every living cell; even the blood vessels themselves are fed by blood vessels. Highways narrow down to one-lane roads, then bike paths, then footpaths, until finally the red cell must bow sideways and edge through a capillary one-tenth the diameter of a human hair. In such narrow confines the cells are stripped of food and oxygen and loaded down with carbon dioxide and urea. If shrunken down to their size, we would see the red cells as bloated bags of jelly and iron drifting along in a river until they reach the smallest capillary, where gases fizz and wheeze in and out of surface membranes. From there red cells rush to the kidneys for a thorough scrubbing, then back to the lungs for a refill. And the journey begins anew.
A person can live a day or two without water and several weeks without food, but only a few minutes without oxygen, the main fuel for our 100 trillion cells. Heavy exercise may increase the demand for oxygen from the normal 4 gallons up to 75-gallons an hour, prompting the heart to double or even triple its rate to speed red cells to the heaving lungs. If the lungs alone cannot overcome the oxygen shortage, the red cells call up reinforcements. Instead of 5 million red cells in a speck of blood, 5 or 8 million will gradually appear.
The pell-mell journey, even to the extremity of the big toe, lasts a mere twenty seconds. An average red cell endures the cycle of loading, unloading, and jostling through the body for 1/2 million round trips over 4 months. In one final journey, to the spleen, the battered cell is stripped bare by scavenger cells and recycled into new cells. 300 billion such red cells die and are replaced every day, leaving behind various parts to reincarnate in a hair follicle or a taste bud.
The components of this circulatory system cooperate to accomplish a simple goal: nourishing and cleansing each living cell. If any part of the network breaks down - the heart takes an unscheduled rest, a clot overgrows and blocks an artery, a defect diminishes the red cells' oxygen capacity - life ebbs away.
- excerpt is taken from In His Image by Philip Yancey and Dr. Brand, pgs 57-8
The cleansing power of blood
If you wish to grasp the function of blood as a cleansing agent, find a blood pressure test kit and wrap the cuff around your upper arm. Have a friend pump it up to about 200mm of mercury, a sufficient pressure to stop the flow of blood in your arm. Initially your arm will feel an uncomfortable tightness beneath the cuff. Now comes the revealing part of the experiment: perform any easy task with your cuffed arm. Merely flex your fingers and made a fist about ten times in succession, or cut paper with scissors, or drive a nail into wood with a hammer.
The first few moments seem quite normal at first as the muscles obediently contract and relax. Then you feel a slight weakness. Almost without warning, after perhaps ten movements, a hot flash of pain strikes. Your muscles cramp violently. If you force yourself to continue the simple task, you will likely cry out in absolute agony. Finally, you cannot force yourself to continue; the pain overwhelms you.
When you release the tourniquet and air escapes from the cuff with a hiss, blood rushes into your aching arm and a wonderfully soothing sense of relief floods your muscles. The pain is worth enduring just to experience the acute relief. Your muscles move freely, soreness vanishes. Physiologically, you have just experienced the cleansing power of blood.
The pain came because you forced your muscles to keep working while the blood supply to your arm was shut off. As muscles converted oxygen into energy, they produced certain waste products (metabolites) that normally would have been flushed away instantly in the bloodstream. Because of the constricted blood flow, however, these metabolites accumulated in your cells. They were not cleansed by the swirling stream of blood, and therefore in a few minutes you felt the agony of retained toxins.
- excerpt is taken from In His Image by Philip Yancey and Dr. Brand, pgs 74-5
The cleansing power of blood
The body performs its janitorial duties with impressive speed and efficiency. No cell lies more than a hair's breath from a blood capillary, lest poisonous by-products pile up and cause the same ill-effects demonstrated by the tourniquet experiment of Day 3. Through a basic chemical process of gases diffusion and transfer, individual red blood cells drifting along inside narrow capillaries simultaneously release their cargoes of free oxygen and absorb waste products (carbon dioxide, urea, and uric acid, etc.) from these cells. The red cells then deliver the hazardous waste chemicals to organs that can dump them outside the body.
In the lungs, carbon dioxide collects in small pockets to be exhaled with every breath. The body monitors the expiration cycle and makes instantaneous adjustments. If too much carbon dioxide accumulates, as when I burn more energy by climbing a flight of stairs, an involuntary switch increases my breathing to speed up the process.
Complex chemical wastes are left to a more discriminating organ, the kidney. The body values these organs greatly as one-fourth of the blood from each heartbeat courses down the renal artery to the twin kidneys. That artery divides and subdivides into a tracery of tubules so intricate as to bedazzle the finest Venetian glassblower.
Filtering is what the kidney is all about, but in very little space and time. The kidney manages speed by coiling the tubules into a million crystal loops, where chemicals can be picked over one by one. Since red cells are too bulky for those tiny passageways, the kidney extracts the sugars, salts, and water from the blood and deals with them separately. This segregation process roughly compares to a master mechanic who has a garage too small to fit a whole car inside. To repair a car engine, he hoists it out of the car, carries it to the garage, disassembles and scours each individual valve, piston, and ring, then reassembles the hundreds of parts minus the grime and corrosion.
After the kidney has removed the red cell's entire payload to extract some 30 chemicals, its enzymes promptly reinsert 99 percent of the volume into the bloodstream. The 1 percent remaining, mostly urea, is hustled away to the bladder to await expulsion, along with whatever excess water the kidney deems expendable. One second later, the thunder of the heart resounds throughout the body and fresh blood surges in to fill the the tubules.
Other organs enter into the scavenging process also. A durable red cell can only sustain the rough sequence of freight-loading and unloading for a 1/2 million circuits or so until, battered and leaky as a worn-out river barge, it nudges its way to the liver and spleen for one last unloading. This time, the red cell itself is picked clean, broken down into amino acids and bile pigments for recycling. The tiny heart of iron, "magnet" for the crucial hemoglobin molecule, is escorted back to the bone marrow for reincarnation in another red cell. A new cycle of fueling and cleansing begin.
- excerpt is taken from In His Image by Philip Yancey and Dr. Brand, pgs 76-7
Overcoming - The White Blood Cell
Battle imagery is appropriate to describe what happens inside our bodies, for with an array of menacing weapons and defenders, our bodies, quite simple, declare war on invaders. At the first sign of invasion numerous body systems hasten into action. Capillaries dilate, like inflatable tunnels, to allow a swarm of armed defenders into the combat zone. White blood cells of 5 distinct types form the initial assault forces. Transparent, bristling with weapons and possessing a Houdini-like ability to slip between other cells, the white cells are the body's chief fighters.
White cells resemble fried eggs sprinkled with pepper, each dot marking a deadly chemical weapon. As the white cells circulate in the body they assume roughly spherical shapes and resemble pale glass eyes aimlessly adrift in the blood vessels. When an invasion hits, they abruptly come alive.
Some white cells, armed with crude chemicals, serve as shock troops and attempt to overwhelm the invaders through sheer numbers. Others with massively shielded cell walls roll in with heavier ammunition, like battle tanks. Attack strategy differs also. Some white cells free-float in the bloodstream, sniping at strays. Some stalk the vital organs, alert for any invader that may slip through initial defenses. Other try to corral invaders into a fortress-like lymph gland for execution. And still others, the sanitary corps, linger until the battlefield is strewn with the bits of cells and leaking protoplasm, then move in to clean up after the melee.
During healthy periods, 25 billion white cells circulate freely throughout the blood and 25 billion more loiter on blood vessel walls. When an infection occurs, billions of reserves leap from the marshes of bone marrow, some in inchoate form like beardless young recruits pressed into service. The body can quickly mobilize 10 times the normal number of white cells.
We need vast number of white cells for one reason: some lymphocytes are "specific" defenders, programmed against only one type of disease. In truth the battle within resembles not so much a one-on-one infantry assault as a furious mating dance in which white cells crowd against the bacteria or viruses seeking the right "fit" before calling up reserves. The average white cell lives merely ten hours. But a select few live for 60 or 70 years and preserve the chemical memory of dangerous invaders, all the while checking in at their assigned lymph gland every few minutes. These master cells safeguard the chemical secrets that remind the body how to respond to any invader previously encountered.
A white cell must somehow home in on the actual invaders who are camouflaged by the chemical smoke-screen of battle and the rubble of leaking cells, clotting agents, and broken membranes. Antibodies guide the white cell through the fray to its intended target. Only 1/1000 the size of bacteria, antibodies cling to the enemy like moss to a tree, softening them up for the approaching white cells and neutralizing their destructive spike shapes. A single antibody protects against only one disease; for example, measles antibody has no effect against infantile paralysis.
Because of the staggering range of invaders confronting a person in a lifetime, the body must stockpile an enormous arsenal of weapons. Dr. Glasser calls the process "a mixture of mystery and chemistry...a combination of physics and grace down at the molecular level."
If I cut my hand, roaming antibodies tag the known invaders, or antigens, almost immediately. In the event a new one is spotted, a circulating lymphocyte cell touches it, memorizes its shape, and rushes to the nearest lymph node. There, that lymphocyte transmogrifies into a veritable chemical factory and conveys the newly acquired information to thousands of other lymphocytes that in turn produce billions of antibodies. Once the lymph produces an antibody, it permanently stores the formula so that a subsequent invasion will incite a fast-motion repeat of the process.
- excerpt is taken from In His Image by Philip Yancey and Dr. Brand, pgs 83-5
The Human Faculty of Hearing
The human faculty of hearing is impressive. Ordinary conversation causes air molecules to vibrate and move the eardrum a mere 10,000th of a centimeter, but with enough precision for us to differentiate all the sounds of human speech. The eardrum membrane has the flexibility to register the drop of a straight pin as well as the noise of a New York subway one hundred trillion times louder. ...if ear sensitivity increased by a tiny amount, we would hear the movement of air molecules as a constant whishing sound.
Three tiny bones, informally known as the hammer, anvil, and stirrup, transfer the vibration into the middle ear. Unlike every other bone, these do not grow with age - a one-day-old infant has them fully developed. They are in constant, unrelieved motion, since every sound that reaches us causes these bones to swing into action. Working together, they magnify the force that vibrated the eardrum until it is 20 times greater than when it entered.
Inside an inch-long chamber known as the Organ of Corti, the force than began with molecules of air and was converted to a mechanical pounding finally ends up as a turbulent fluid force. The action of the 3 bones sets up pulsating waves in the viscous liquid inside the sealed Organ of Corti. Everything we know as sound depends on this seismic chamber.
How do I distinguish two different sounds, such as a buzz of a fly droning about and the rumble of the lawnmower? Every distinct sound has a "signature" of vibrations per second. If you hear a wave of molecules oscillating 256 times/sec, your are hearing the musical "middle C." The average person can detect vibrations from 20 to 20,000 cycles/sec.
Inside the Organ of Corti, 25,000 sound receptors line up to receive these vibrations, like strings of a huge piano waiting to be struck...Each cell is designed to respond to a certain pattern of sound. A few of these cells will fire off signals to the brain when a 256-cycle vibration reaches them, and I "hear" a middle C. The others will await their own programmed frequency. Imagine the moiling chaos of cell activity when I sit in front of a full orchestra and hear twelve different notes at once, as well as the variety of musical "textures" from the different instruments. In all, the human ear distinguishes some 300,000 tones.
In considering the brain, the most important fact about hearing is that the vibration itself never reaches the brain. The process resembles a cassette tape which absorbs sound not as a mechanical vibration but as a series of electrical and magnetic codes. Once the vibration excites its appropriate sound receptor cell, the force inside the head changes from mechanical to electrical. Thousands of wires, or neurons, lead from the patch of 25,000 cells into the auditory part of the brain. There the frequencies are received in a sequence of on-or-off blips. Our experience of sound depends on which of these cells transmits its signal, how often, and in cooperation with what other cells. The brain pieces together these messages and we "hear."
After receiving the electrical code from the sound receptors, the brain makes its own contributions of meaning and emotion.
- excerpt is taken from In His Image by Philip Yancey and Dr. Brand, pgs 110-112
The Human Faculty of Smelling
Smell leaves the world of quantifiable physics and approaches mystery. ...Smell operates by direct chemical action: tiny olfactory receptors perform elaborate chemical tests on any stray molecules that float by. ...In humans a penny-size patch of receptive tissue lies at the top of our nasal cavities. For a good analysis we must sniff in, forcing the molecules up to the sensitive spot and then trapping them in the sticky moisture of the nasal lining. Even with our more primitive systems, we can detect one garlic molecule in the waftage of 50,000 other molecules.
The nose is an organ of nostalgia. The smell of coffee, a whiff of briny seashore, the faintest lingering trace of a certain perfume, or the etheric order of a hospital corridor can stop you like a bullet. You relive that former moment in a flash, jerked backward in time by the fragrance locked away in your brain. ...The brain faithfully squelches odors after an initial heightened period...Smell is primarily a sentinel warning and, once warned, why should the brain be troubled with redundancy?...We humans possess baffling powers capable of discriminating some 10,000 different odors, yet is there any sense we attend to less or take for granted more?
- excerpt is taken from In His Image by Philip Yancey and Dr. Brand, pgs 113-114
The Human Faculty of Taste
Taste suffers in comparison to smell and, in fact, relies mostly on smell, as any chef or any eater with a stopped-up nose can confirm. An electron microscope scan of the tongue's dense mat of taste buds reveals splendid structures: dramatic cliffs and caverns, cactus flowers, clusters of tall, waving stalks, exotic leaves. They work well enough to afflict most of us with lavish appetites and insatiable cravings. But it takes 25,000 times as much of a substance to register on a stubby taste bud as it does to register on a smell receptor. And for some mysterious reason, taste buds live a mere three to five days, then die off, so the only "experienced" taste exists in the fortress of the brain. ...The experience of taste stimulates the gastric juices in the same way the smell of a sizzling steak or frying bacon can awaken in us a sudden, unexpected hunger.
- excerpt is taken from In His Image by Philip Yancey and Dr. Brand, pgs 115
The Human Faculty of Sight
The human eye's characteristic coloring comes from the iris, comprising radial and circular muscles that assist in opening and closing the pupil, thus increasing or decreasing the amount of light permitted by a factor or sixteen. A camera f-stop shutter duplicates this mechanical function, but nothing duplicates the lovely texture of those exquisite muscles that ripple and flute like the gills of a tropical fish. Inside, a precision lens, made of living tissue, is slung with transparent protectors and kept in position by a clear liquid that renews itself constantly to nourish the cells and kill stray germs. In children, the lens has a startling crystalline transparency. Later, protein deposits accumulate, harden, and scumble the clear lens, causing a condition called "Cataracts."
The complexity of perceptual cells beggars the imagination. In humans, 127,000,000 cells called rods and cones line up in rows as the "seeing" elements that receive light and transmit messages to the brain. Rods, slender and graceful tentacles that reach out toward light, outnumber the bulbous cones 120,000,000 to 7,000,000. These rod cells are so sensitive that the smallest measurable unit of light, one photon, can excite them. Under optimum conditions the human eye can detect a candle at a distance of 15 miles. Yet with rods alone, we would see chiaroscuro, only shades of black and gray, and would not get the focal resolution allowed by the more complex cones.
Squeezed into the dense forest of rods, the larger cones tend to concentrate in the precise spot in the eye where focusing is most acute. Although cones are one thousand times less sensitive to light, they make possible all perception of colors and fine details. ...Our assortment of rods and cones lets us see objects at the ends of our noses and also stars light-years away.
...Our brains do not receive photographic images of anything. Rather, some of the 127,000,000 rods and cones get "excited" by light waves and fire off messages into the 1,000,000 fibers of the optic nerve, which coils like a thick television cable back into the recesses of the brain. Impulses from the retina race along the fibers of the optic nerve, fan out in the brain, and finally slam into the visual cortex, stimulating the miracle of sight.
The cortex has no easy task, since one billion messages a second stream in from the retina. Only in the last few years have scientists gained a glimpse into how the visual cortex sorts out these electrical signals.
...This ability to transpose units of messages, whether from the ear, the nose, the tongue, or the eye - into ever-higher strata of meaning is only possible because of the inner functions of the secluded brain. Cells inside that ivory fortress have no immediate experiences of light, sound, taste, or odor. Yet every bit of data transmitted by sense organs terminates there. Indeed, no sensation truly registers until the brain has taken hold of it, translated it, and made sense out of it.
- excerpts are taken from In His Image by Philip Yancey and Dr. Brand, pgs 116-119
The Brain - Pt 1
Eminent neurologist Sir Charles Sherrington neatly divided certain brain nerve cells into two groups: "the way in," or afferent cells which carry impulses from the organs of the body to the brain, and the "the way out," efferent cells which carry instructions from the brain out to the extremities. The the entire brain, only one in one thousand cells reports in from the extremities: all the visual images, all sounds, all touch and pain sensations, all smells, the monitors of blood pressure and chemical changes, the sensations of hunger, thirst and sex drives, muscular tension - all the "noise" from the entire body - occupy 1/10 of 1% of the brain's cells. Each second those fibers bombard the brain with a 100 million messages. Of these, a few hundred at most are admitted above the brain stem.
Another 2/10 of 1% of cells control all motor activities: the motions involved in playing a piano concerto, speaking a language, dancing a ballet, typing a letter, or operating a video game. In between these two groups, the Way In and the Way Out, lie all the others: enormous numbers of cells cooperating in a vast network of intercommunication to allow the processes we know as thought and free will.
...Unlike a telephone switchboard that connects single subscribers indirectly through a central switching station, each nerve cell in the brain has up to 10,000 of its own private lines. All along its length dendrites reach out and form connections with other neurons, in effect linking each cell with wires from an entire city. It "listens in" for the patterns of impulses and their average rate of arrival and decides whether to continue the message by firing off chemicals along its thousands of other connections.
Physiologically, the whole mental process comes down to these 10 billion cells spitting irritating chemicals at each other across the synapses or gaps. The web of nerve cells defies description or depiction. One cubic millimeter, the size of a pinpoint, contains 1 billion connections among cells; the mere gram of brain tissue may contain as many as 400 billion synaptic junctions. As a result, each cell can communicate with every other cell at lightning speed - as if a population far larger than earth's were linked together so that all inhabitants could talk at once. The brain's total number of connections rivals the stars and galaxies of the universe.
- excerpts are taken from In His Image by Philip Yancey and Dr. Brand, pgs 126-27
The Brain - Pt 2
Even in sleep the nerve cell community never stops chattering. The brain is a turbulent cloud of electrical potentials. During each second of life it performs about 5 trillion chemical operations. When we are awake, only a few reach our level of consciousness, and those so quickly we are hardly aware of the process.
In a biological sense a whole body exists just to keep the brain nourished and protected. The brain uses up 1/4 of all the oxygen its owner breathes - lack of oxygen for 5 minutes causes its death.
One nerve controls all the subtle movements of the lips that make speech and eating and kissing possible. Another brings in every nuance of color and light to form the visual construct of the world.
The brain contains imagination, morality, sensuality, mathematics, memory, humor, judgment, religion, as well as an incredible catalog of facts and theories and the common sense to assign them all priority and significance. In the human head, concludes Nobel laureate Roger Sperry, "there are forces within forces within forces, as in no other cubic half-foot of the universe that we know." There is nothing on the earth so wonderful.
- excerpts are taken from In His Image by Philip Yancey and Dr. Brand, pgs 128-9
Life depends on our ability to stay in contact with the vital element of oxygen around us. When deprived of air for any length of time, the patient actually turns blue, first around the fingernails, tongue, and lips, projecting the internal drama onto the visible screen of skin. High school students learn what causes the color shift: blue blood has not gotten the supply of oxygen from the lungs that normally turns it a rich scarlet. The animal kingdom lives in utter dependency on this one element, oxygen.
Some lower animals' devices for gathering oxygen are inexpressibly beautiful: the jewellike fronds of marine worms, the fluted gills of tropical fish, the brilliant orange skirt of a flame scallop. Our own lungs come down on the side of function, not form, but they work well enough to make an engineer drool. The beginning medical student who first cuts into a corpse's torso gets graphic evidence of the lungs' importance. They crowd all the rest, spilling into every crevice and cranny. When air is pumped in to stimulate breathing, they seem to want to burst out of the chest cavity.
Bronchial tubes from the throat bisect, narrow down, divide again, and fan into a tress of tubes that culminate in 300 million sacs called alveoli. The sacs, only 1 cell thick, are caught like dewdrops in a spider web of blood vessels that channel blood around the alveoli for the all-important oxygen transfer. The folds and convolutions of the lungs result in a surface area 40 times larger than the skin's, an area large enough to carpet a small apartment.
We need the space. On an average day our lungs move enough air in and out to fill a medium-size room or blow up several 1000 party balloons. Each breath sucks in about a pint of air, and if we don't think about it we take around 15 breaths a minute. Any slight change, such as going up stairs or running for a bus, can double the capacity of air per breath and also double the intake frequency. Receptor centers scattered around the body constantly take oxygen and carbon dioxide measurements to determine the ideal rate. The entire process continues uninterrupted during sleep, without conscious control, or we would die. And the utilitarian body makes us borrow the same air flow system for such acts as speaking, singing, laughing, sighing, and whistling.
...The lungs of a non-smoker from the country have a gorgeous pink sheen of health. Tiny blood vessels show clearly against their light background. In dramatic contrast, the lungs of a city-dwelling smoker are dull charcoal in color, almost as dark as those of a coal miner. Perhaps if the skin on our chest were transparent membrane like a tropical fish's so that every person could see for himself that contrast, as well as the fungoid ugliness of lung cancer, our society might undergo some major changes.
- excerpts are taken from In His Image by Philip Yancey and Dr. Brand, pgs 169-70
An animal crosses the road, my foot instinctively taps the brake pedal. An out of control skid begins, hands on the wheel, a few jerks of the wrist and the car straightens out. The instinct all started in the brain.
When the sight of the animal reached my visual cortex, a trained reflex response directed my foot onto the brake pedal. After that, my hypothalmus ordered up chemicals to launch with lightning speed a series of reactions designed to put me in prime condition to cope with the alarm.
Few parts of my body go untouched by the crisis. First, my vision intensifies as my pupils dilate. All my muscles go on alert. Stress hormones affect my entire circulatory system. My heart beats faster, contracting more forcefully, and even in the extremities vascular muscles relax in order to allow blood vessels to change: more blood sugars surge in, providing emergency reserves for working muscles, and clotting materials multiplied in preparation for wound repair. Bronchial tubes flare open to allow faster oxygenation of the blood.
On my largest organ, the skin, blood vessels contract, bringing on a pale complexion but lowering the danger of surface bleeding in case of injury. A reduced volume of circulation in skin also freed up more blood for the muscles' urgent need. The electrical resistance of skin changed as a protective mechanism against potential bacterial invaders. "Goose-pimples" bulge up all over my body, holding erect millions of hair shafts. Sweat glands pour out assistance to increase the traction of my palms on the steering wheel.
Meanwhile nonessential functions slow down. Digestion nearly comes to a halt - blood assigned to that and to kidney filtration is redeployed for more urgent needs.
Outside not much happened. I avoided the animal and corrected the skid. Yet inside, a full-scale battle was fought and won to equip me for the classic alternatives of "fight" or "flight." A single unifying chemical messenger, adrenaline, managed to coordinate an entire galaxy of select cells.
We experience the effects of adrenaline every day: we are startled by a loud noise, we hear a bit of shocking news, we drive through a dangerous neighborhood, we stumble and nearly fall. Adrenal reactions occur so smoothly and synchronously that we rarely, if ever, stop to reflect on all the elements involved. And yet adrenaline is just one of the many hormones at work in my body coaxing a cooperative response from diverse cells.
- excerpts are taken from In His Image by Philip Yancey and Dr. Brand, pgs 189-90