Your Body—Marvel of Engineering Excellence
LONG before the development of man-made engineering marvels, there existed a structure far superior to any of them. This structure is the human body.
The some six hundred muscles of your body burn fuel, even as does the engine of an automobile, converting this fuel into usable energy. But the human body is far superior to the automobile in that it manufactures its own fuel from raw materials, does its own cleaning and repairing, and replaces worn-out cells by the millions each day. Would it not be wonderful for car owners if their automobiles could do the equivalent of that?
Ages before engineers of ancient Rome constructed the dome atop the Pantheon, the dome of the human skull already roofed the human head. And millenniums before those Roman engineers built arches to support their aqueducts, the arches of the foot provided springy support for the body’s weight, and the arched ribs formed a highly efficient flexible cage protecting the organs within the chest. Also, long before the great Greek and Egyptian columns were conceived, man was being held upright by his own columns, his legs.
Your bones, for combined strength and flexibility, far surpass building materials devised by man. The shinbone can bear about thirty times the weight of the man resting upon it. Iron itself would be no stronger. And iron would be too rigid to accommodate the stresses of body motion, and far too heavy for practical purposes.
Encasing the body’s bony structure are tissues that neither splinter, chip nor weather away as do man-made building materials such as wood, brick, cement, stucco and paint. Your eyes have eyelashes for protective shades, eyebrows as overhanging eaves, and shutters that close automatically. The internal organs of your body are surrounded with fluid that acts as a shock absorber. Truly, as engineers engaged in the field of bioengineering continue to study the human body they cannot help but marvel at its engineering excellence.
Pumping, Filtering, Circulation
Consider a pump that no human engineer could ever duplicate perfectly—the heart. This tiny pump pulsates, on the average, seventy times a minute, forty million times a year and passes about 7,000 quarts of fluid a day, nearly 200,000 tons in the average lifetime.
Nor can any manufacturer of industrial specialties offer a high-pressure filtering apparatus like the kidneys. These consist of approximately two million filter units complete with filter sheet, strainer and reabsorbing mechanism. The kidneys can filter 200 quarts of fluid daily, though being comprised of only two structures, each small enough to fit into the palm of your hand.
Consider also the circulatory system of the body. It can be likened to a city’s system of roads, railroads and shipping facilities that supply the daily needs for food and necessary materials of life. A city also has a system of sewage, sanitation and waste disposal. Similarly, the human body is served by blood circulation that provides the distribution of supplies and removal of wastes.
The United States, for example, has many miles of roads to supply food to its some 200 million inhabitants. However, the human body alone has about 100,000 miles of “roads” and “pipelines”—arteries, veins, and capillaries—which transport the life-sustaining nourishment to some 30,000,000,000,000 cells! And how long does it take the body’s some five quarts of blood to make a complete circuit of this vast system? Astonishing as it may sound, it takes only about one minute!
Traffic problems of the body’s “roads” for circulation are ingeniously controlled to perfection. The blood, for instance, can go in only one direction. This one-way movement is achieved by ideally engineered valves built into our veins, known in engineering terms as “check valves.” The blood is pumped by the heart through the arteries under great pressure to the capillaries. Then, returning to the heart from the lower extremities under very little pressure, the blood is forced upward through the veins by the exertion of leg and stomach muscles. The tightening and contracting of these muscles force the blood through the veins. In addition to the muscle action, flow in the direction of the heart is maintained by means of the “check valves.”
But how is it that an even supply of blood is provided throughout the thousands of miles of the body’s circulatory system? In any piping system where a fluid is circulated for a specific purpose, say, that of sending hot water throughout a building to radiators for heating, consideration must be given to the control of the quantity of water flowing to each radiator. Throttling or balancing valves must be installed to assure even water distribution throughout the system.
Thus, too, an even flow of blood throughout the human body is achieved by means of stopcocks in the tiny arteries in the tissues and organs. These control the volume and flow of blood, whether near the heart or remote from it. In addition to controlling the proper flow of blood to each organ, these stopcocks will open and allow an increase of blood flow above normal if temporary circumstances may require it. Truly, in the body, we can readily see the marvels of hydraulic and traffic engineering in their finest form.
Thermal and Environmental Control
Modern engineers construct buildings that maintain year-around comfort regardless of exterior weather conditions, whether it may be extremely hot or bitterly cold outside. However, your body far surpasses the most elaborate environmental control system. It regulates its temperature with an ingenious application of thermostatic control. Regardless of the surrounding air temperature, the body’s thermostatic controls keep the tissue at about 98° to 99° F.
In the cold of winter, we know that heat is obtained by the burning of a fuel of some sort. As the fuel burns, a combustion process takes place and heat is released by means of oxidation. But what about your body? How is heat generated in your body, since there are no “fires” within you?
Actually the body utilizes a combustion process, and heat is derived from oxidation. Glucose is manufactured in the body, and molecules of glucose are shattered within the body and energy is subsequently released as heat. This production of your body heat is known as metabolism.
Then, too, when exposed to the cold, have you noticed that your muscles become tense? This also is one of the body’s ways of producing heat, employing the use of the muscles. If you get cold enough you begin to shiver. Commenting on the effects of muscle tension and shivering, Professor Arthur C. Guyton, noted physiologist, states in the Textbook of Medical Physiology:
“The resulting muscle metabolism increases the rate of heat production, often increasing total body heat production as much as 50 percent even before shivering occurs. When shivering begins, body heat production can rise to as high as 200 to 400 per cent of normal.”
Equally amazing as the body’s heat-generating system is its cooling system. When exposed to warm weather, we perspire. This is the body’s way of dissipating heat by evaporation. Evaporation, basically speaking, is one of the main principles modern refrigeration. The evaporation of the water produces the cooling due to the change from water to vapor. Yet your marvelous body was employing this technique long before human engineers began using it.
The lens of the human eye is still another marvel. Through this lens various forms are perceived; then they are focused on the retina. Eye focus is similar to the optical system of a camera. The lens adapts to distance by changing shape. But whereas a camera is manually adjusted, the lens of the eye automatically changes its thickness and curvature to adjust the focal point for various distances.
There is another interesting phenomenon in connection with human sight. This has to do with the fact that when an object is transmitted through a convex lens, such as we have in our eyes, the image transmitted appears inverted, or upside down. This is how images are transmitted to the retina and subsequently to the brain. But our brain automatically interprets the image so that the world does not look upside down to us, but right side up. It is simply another example of the ingenious operations of the body.
Such a brief examination of the engineering marvels of the human body should deeply impress upon one the wisdom of the Grand Creator of the human body. An honest-hearted, intelligent person is moved to say to God as did the Bible psalmist of long ago: “I shall laud you because in a fear-inspiring way I am wonderfully made.”—Ps. 139:14.