Thursday, October 7, 2010

Fearfully and Wonderfully

Psalm 139 declares that we are fearfully and wonderfully made. Over more than twenty five years spent caring for a wide variety of sick and injured bodies I have come to agree with the profound truth of this statement. The human body is constructed in a remarkable way that keeps it running during the most trying situations.

From the top of our heads to the soles of our feet our bodies are constructed to withstand extremes of temperature, assaults by invading organisms, physical and mental challenges and to perform with uncanny accuracy under the most arduous and taxing conditions.

So, let us start with the bottom of our feet. The plantar aspect or soles of our feet are a thick layer of skin and fascia perfectly suited for the stress and strain of upright walking. All the trumpeting of modern technological advances in athletic shoe design has not yielded any product that can claim to be superior to our feet. Indeed, recent research suggests that running barefoot or with a flat shoe with minimal padding is far superior to the thick soled, complicated athletic shoes that probably create more stressors for our feet than they prevent. It seems that Hobbits had it right.

Our bodies are maintained at a near constant temperature, 98.6 F or 37.5 C. We are equipped with very efficient heaters and coolers to keep us in the appropriated narrow range. If our body temperature starts to rise, be it secondary to a hot environment, physical exertion or some other factor we will sweat (or perspire if you are a lady). The moisture can cool directly, but the greatest cooling is a result of evaporation from our skin. External adjuncts, such as fans speed the process. Rapid breathing also can contribute to elimination of heat via the lungs. Of course this is carried to an extreme in dogs, who pant to cool themselves.

Conversely, our body is constantly producing heat. Routine, but essential metabolic processes all generate heat. In a cold environment this metabolism speeds up and more heat is generated, often manifested by shivering. Similarly, in the course of many illnesses a patient develops a fever. In the most extreme circumstances an ill patient will develop uncontrollable shaking called “rigors”. Such shaking is the result of rapid muscle contractions designed to generate heat and rapidly raise body temperature. In such situations the “thermostat” is turned up. Body temperature rises from the normal 98.6 to 101 or 103 or even higher. During the rising phase the patient complains that he feels cold and will attempt to cover himself to conserve body heat until the new temperature set point is reached. Although such high fever is a cause for concern and does carry its own set of risks, there seems to be some benefit, aiding our body’s fight against invading pathogens.

The fever may persist or it may dissipate, at which time the patient will usually have profuse sweating that lowers body temperature, the fever “breaks”. The fever must play a role in repelling an invasion by micro-organisms. The higher body temperature seems to have an inhibitory effect on certain viruses and bacteria. In the post operative patient fever is very common. Low grade fever, below 101.5 is probably secondary to a systemic inflammatory response unrelated to infection. Above this level, there is more concern that an infection might be present.

In any scenario, the fever has a purpose, be it fighting infection or assisting with the healing process and is one example of the amazing intricacies of human physiology.

Fever, of course, is a very common occurrence, be it a simple cold or life threatening sepsis. There is an aspect of human physiology and anatomy that is very important to our well being. Our bodies are built with long tunnels passing into and through us. The aerodigestive tract allows us to exchange a variety of elements with the outside world. The tracheobronchial tree starts at a shared entrance with the digestive tract. In the pharynx the two systems divide, with the respiratory limb ending in the lungs, two balloon-like structures that constantly inflate and deflate, exchanging inhaled oxygen for carbon dioxide, a byproduct of cellular metabolism. This essential mechanism keeps us alive. In fact, the first two letters of the ABC’s of trauma resuscitation are Airway and Breathing, (the third is Circulation), the jobs performed by the lungs.

But, it is the efficiency of our lungs and airway in light of constant bombardment by potential pathogens from the world around us that is truly remarkable. Our upper airway is equipped with mucus membranes that secrete mucopolysaccaride chemicals that trap invaders so they can be expelled or killed. Our upper airways are also outfitted with cilia, tiny hair-like structures that rhythmically beat and carry foreign particles away from the lower bronchial tree. We have the ability to cough, an extremely efficient mechanism that clears uninvited strangers from our lungs and trachea. Finally, our alveoli, the tiny balloons where gas exchange occurs, have all the components of our immune system standing at readiness to attack any invaders that make it to that level. Should this final line of defense be overwhelmed by bacteria, viruses or merely large particles, infection and/or impairment of gas exchange occurs. Pneumonia results from micro-organism infection of the lungs. Smoking damages cilia and allows particulate matter to reach the ends of our airways, eventually causing damage that is irreversible, the common condition called Chronic Obstructive Pulmonary Disease (COPD).

The other fork of the aerodigestive tract leads to the esophagus, stomach and the small and large bowel. While the lungs are efficiently scavenging wayward invaders, the gastrointestinal tract has learned to live in harmony with such organisms. Technically, the GI tract lumen is outside our bodies. It is a long, tortuous tunnel that snakes its way from our mouth to our anus. Inside this tunnel trillions of bacteria reside in a symbiotic relationship; welcome, as long as they stay in their place.

The numerous types of bacteria play a crucial role in maintaining normal physiology and immune function. It is likely that the resident bacteria stimulate a variety of immune functions, particularly during the early developmental years. The bacteria help with digestion of certain nutrients, breaking down complex polysaccharides into more digestible forms and also play a key role in the enterohepatic circulation of bile salts. In addition, the GI flora help with the absorption of certain vitamins and play a protective role for their human host by preventing the overgrowth of harmful bacteria within the gut lumen. As long as these tiny helpers stay inside the tunnel of the GI tract they are our friend. If they escape and invade surrounding organs or spaces, then they are most unwelcome. But, the normal GI tract physiology is a wonderful example of symbiosis between vary disparate organisms.

It is easy to see that the human body is an amazing creation that is well suited to living and flourishing in a hostile world. But what is it that sets the human apart from other animals. Other animals may run fever and are also bombarded by microscopic invaders. Is there anything that sets the human apart; an attribute that screams: “I am unique to the Homo sapien; you won’t find me in a dog or a chimpanzee”?

GK Chesterton said it was art that separates humanity from all the rest of creation. The ability to paint, write, sculpt, play or write music is the sole province of mankind. The ability to appreciate such endeavors is an even greater exclusive human attribute.

But what is it that allows a Bach to write music that soars, a Picasso to create unique, expressive paintings or a Charles Dickens to string together a series of words that actually make sense and have the power to entertain and inform? There are two components of the human body necessary for such creation. The first and most obvious is a brain, an organ that is incredibly complex, with mechanisms that are poorly understood, but capable of the most astounding achievement. Every original thought, every idea that became a concept and then a commodity started in the recesses of someone’s brain.

A mass of neurons, synapses, electrical impulses and chemical transmitters work in harmony to produce a thought. This thought may be the next logical conclusion from a series of previous thoughts or it can materialize from nowhere, an inspiration from an unseen Muse. Thoughts may be fleeting or they may coalesce into ideas. Eventually the idea comes to fruition and a new creation emerges. Humanity lurches forward into new realms with every thought and idea. Unfortunately, some ideas seem to cause us to step back.

The passage of idea to commodity requires that some form of work be performed and the principle agent of such work, particularly in the arts, but also in most other endeavors is the hand.

A complex organ made up of skin, bones, nerves, blood vessels and muscle, the hand is capable of turning black and white notes on a page into the sweet sound of Rachmininoff’s Piano Concerto Number Three; it can mold and shape a lump of stone into Michelangelo’s David. This incredibly versatile organ allows us to surpass all the rest of creation, to create the art that we all appreciate.

It is possible to provide substitutes for our hands; amazing creations have come from people who have lost the use of their hands. But, as we marvel at the human capacity to adapt to such disability, consider what these talented individuals could have done. Substitutes for our hands can be fashioned or trained, but they remain substitutes, at best performing nearly as well as a normally functioning hand, but never surpassing the hand.

A whole book could be written on the amazing design of the human body. Many of the intricacies are still being discovered, but it is this remarkable design, this body so perfectly suited to thrive in the world that surrounds us, that allows someone like me to slice a patient open from stem to stern, root around inside for a while, stitch the wound closed and then see that patient walk into my office a month later entirely well. Truly amazing.