Today I went cross-country skiing. It was a perfectly splendid morning; the birds seemed to whisper, “spring!” in their songs, and the sun shone warmly, though the air was crisp and cold. It was a wonderful day to be alive, and I thought what a blessing it was to be able to get outdoors and enjoy it. How many people are shut up in hospitals or nursing homes, or bound to their wheelchairs because of some accident. Who knows, next year at this time, I could be one of them. What better incentive to enjoy to the fullest every wonderful thing about that morning ski expedition!
So as I skimmed along (in between falls), I reveled at the thought of everything that was going right inside of me. Complex electrical pathways in my heart were functioning beautifully, setting off a wonderfully choreographed dance, atria and ventricles contracting in perfect timing, valves snapping shut, the arteries in my heart perfusing beautifully between each beat. I was taking deep, easy breaths, thanks to the special membranes and lubrication that provided negative pressure to open my lungs. Split second transactions of oxygen and carbon dioxide were occurring across delicate, but all important, membranes. Blood was surging through my body, helping my stomach and intestines sort out nutrients and deliver them where needed, and filtering through the liver and spleen and kidneys for the removal of waste products. In my kidneys and certain arteries, pressure receptors measured my blood pressure, which data my brain used to regulate my heart rate and the secretion of hormones to maintain proper blood volume.
Much of the blood was shunted to my muscles, where muscle fibers contracted and relaxed, supplied by energy factories within their cells, and responding to neurotransmitters that were released by precise electrical stimulation across miscroscopic gaps. Those nerves, designed for maximum transmission speed, traced back to my spinal cord and brain, where millions of connections allowed for smooth communication between all the different parts of my body and my brain. The blood headed to my brain, ready to deliver the glucose at the precise concentrations provided by my pancreas and liver. The brain must have the glucose and oxygen to survive—but the blood itself would permanently damage brain tissue, if it wasn’t for a specialized barrier that allowed only the proper substances to pass to those hard-working neurons. My brain was functioning with incomprehensible complexity and precision. It was interpreting an inverted picture from my eyes, and adjusting the size of my pupils to compensate for the brilliant glare of sun on snow. My ears registered a huge span of sounds, from the twitter of birds, to the scraping of my skis on snow, and integrated them with memory to allow me to make sense of my surroundings. The collection of tubes and hairs and tiny stones in my ear also registered my position, and allowed me to keep my balance—at least most of the time. My cerebellum calculated the force with which to contract each muscle, coordinated muscle groups to work together, and signaled instantaneous responses to a slip or slide on the snow.
All this happened without my thought. But if any of those functions had stopped working, I would have been in big trouble—perhaps soon ending up in the ICU where I work. As it was, I had plenty of free mental power to contemplate the splendor of the world around me, the mind-blowing wonder of the world within me, and the God Who made both of them.
One thing that I love about my job is that it’s teaching me not to take anything for granted, a single breath of air, a single pulse of my heart, a single effortless muscle contraction, a single swallow of food. There may come a day when I would give anything to be able to catch a breath on my own, or to be able to take a single step. Unless the Lord Jesus returns first, there is going to be a time when my heart pumps for the last time, when my neurons fire and then are still forever, when my kidneys stop working and I’ll be killed silently by raging chemical imbalances. There will almost certainly be a day when I will catch my final glimpse of sunshine, feel the wind no more blowing into my face and down my collar. When the beauty of a winter day will call for me in vain, because my steps are too feeble to venture outdoors. I’ll never be able to hear the birds call again, or perhaps I’ll never be able to see a blue sky or smell spring in the air. Then, I will wish that I had enjoyed it more when I had the chance. I’ll regret that I didn’t fully appreciate the wonder and beauty of life. So laugh if you will at my fascination with the anatomy and physiology of life. I sure enjoyed that morning ski!