Heart

I’m reposting this piece in honor of the new year.  It occurred very early in my blog:

Heart shapes can be found in nature, if you’re lucky enough to spy one.  There’s a heart on Jabu’s trunk, a ridge of skin that feels like fine shoe leather.  One of his wrinkles pierces the lower third of this heart shape, from left to right, straight as an arrow.  His real heart hangs between his breastbone and ribs, a little to the left, just like mine does.  But instead of having a heart with a single point, an elephant’s heart has two points at its apex – so it’s the wrinkled outline of a human heart that Jabu carries on his trunk.

The length of Jabu’s real heart is about twenty-two inches, its width eighteen.  His heart weighs around forty-four pounds, almost the same as a medium-sized dog.  Still, it’s less than 1% of his body weight, a common proportion among large mammals and among humans.  My heart also weighs less than 1% of my body weight: about ten ounces.

The human heart is approximately five inches long, three-and-a-half inches wide and shaped like a pulsing cone.  It is the only muscle in my body that acts on its own – my heartbeat doesn’t need any messages from my brain.  The cells in my heart tissue involuntarily constrict, all together, all at once, over and over, a soft perpetual-motion machine.  Rip my heart from my body, chop it into pieces, immerse the pieces in a saline solution, and then give them a small jolt of electricity.  The remnants of my cardiac muscle will contract . . . contract . . .  contract – all on their own, sometimes for hours.

It’s designed to be strong, my heart.

In mammals, birds, and reptiles the heart has the same basic pump-like design, a design that has worked through eons – even cold-blooded dinosaurs had hearts.  A day or two after fertilization, embryos develop a pinpoint that pales, then brightens, pales, then brightens, the beginnings of a tiny pump practicing emptying, filling, emptying, refilling.  An old, old pattern.  The master timepiece.

There are four chambers in my heart: two auricles (“little ears”) and two ventricles (“little bellies”) – named by anatomists for the external parts of the body they resemble.  Spent, dark-red blood is collected in the right auricle, then dropped into the right ventricle, which constricts and pumps it out to the lungs to pick up oxygen.  Bright red again, full of oxygen, blood circulates back to the left auricle and from there drops into the left ventricle.  In the next twitch blood is delivered to every corner of my body.

The “little ears,” the auricles, make very little sound as they drain blood into the lower chambers of my heart, a distance of an inch or so.  It’s the ventricles, the “little bellies,” that boom as each contraction forces open heart valves and blood gushes up the aorta under pressure.  Lupp DUPP.  Lupp DUPP.  Lupp DUPP.  One beat smaller, one beat larger, flush after flush.

My right ventricle has walls thin as paper – it delivers blood only as far as the lungs.  If I could hold it up to the light I could see right through it.  The left side of my heart is the heavyweight lifter, pumping blood all the way to my toes, moving 150,000 tons of blood in my lifetime.

Jabu’s great artery, the aorta, takes off from the left ventricle of his heart, the same as mine does.  Named in the Middle Ages, aorta means, “to heave.”   It’s an artery more flexible and sturdier than any manmade pipe.  Jabu’s left ventricle pumps a continuous stream of blood up and out of his heart into the aorta, which then drops down into his chest and down each leg, where it branches and branches and branches all the way to his toes.  Each arterial branch has less space than the artery it came from, but the sum of  their volume is always greater than their mother artery.  The blood moves, but more and more slowly through smaller and smaller pipes, trickling into all corners of Jabu’s body, trickling through capillaries one cell thick.

Blood’s trip back to the heart is made through veins.  Millions of tiny venules drain into thousands of small veins, thousands drain to hundreds, hundreds to the one that empties back into the heart.  Veins are even more elastic than arteries, can hold variable quantities of blood, and serve as a reservoir for all that moving liquid.  At any one moment, 65% of my blood is contained in my veins.  It’s an ancient blueprint, this branching, this heartbeat, this coming and going, a blueprint brought to life in even the tiniest of creatures.

Blood has to be literally hoisted from Jabu’s toes.  Squeezed along by muscles wrapped around veins, pushed by valves in the veins, and sucked upward by the huge action of breathing, blood finally arrives in the vena cava, where it drops into the heart.  Jabu has two vena cavae, possibly because of the large amounts of blood that need to be moved.  The blood vessels of an African elephant reach lengths of twelve feet, a huge network of life.

Jabu’s body contains 120 gallons of blood, enough to fill an aquarium six feet long, two feet wide and two feet deep.  At one-and-a-half gallons, my puny amount of blood would barely fill a birdbath.

Blood is the body’s only liquid organ, five times denser than water.  It takes food and water in, removes waste and byproducts to the disposal areas of the body, the kidneys, lungs, and skin.  Blood irrigates all tissue, both feeds and cleanses.  It leaves the heart at one mile per hour and returns, laden with waste, at about half that speed.  Construction materials move along highways of blood, demolished materials return.  Blood is 20% solids and 80% water, carrying products of digestion, products made by the body, foreign intruders, the dust of stars, even cobalt from the original ocean of the earth where both of us, human and elephant, began our journeys.

We each have roughly one billion heartbeats for our lives.  Mouse, hummingbird, elephant, human, all the same.  Like us, elephants suffer cardiovascular disease, die of heart attacks and strokes.

Cardiac arrest: when the heart shudders and stops, when the light in the eyes flickers, fades and snuffs.

And when the heart quits beating, its resonance

Lupp DUPP     Lupp DUPP     Lupp DUPP

is gone.  The gurgle of digestion, all the silky, sturdy, slapping noises, the blood rush, gone.  The symphony of the body is finished.

For those of us left, that silence is almost too much to bear.