WHEN the Bible uses the term breath of life it is not just using a figure of speech. From earliest times men have known that breathing is connected with life. Only in the recent history of man, however, have we really be gun to understand the details of how vital breath really is to life, and specifically how the breathing mechanism of the body functions. The Adventist worker who must participate in such health evangelism activities as Five-Day Plans to Stop Smoking certainly needs to understand the breathing mechanism and its function.
The separation of oxygen from the air is accomplished in the lungs and is an extremely important and delicate work. It is essential because the cells of the body need oxygen, and this is part of the mechanism the Creator has designed to provide the body with this life-sustaining element.
The lungs are suspended in thin, membranelike pleural sacs, like one balloon within another, facilitating their movements. The air passage known as the trachea, or windpipe, forks into the smaller pipes called bronchi, which in turn divide like the branches of a deciduous tree. Branching is usually into two branches. A careful study of the diagram below will reveal that at each division there is a keel-like, sharp, leading edge designed to reduce resistance to air flow. The sum of the area of the branches dividing off at any given trunk is always a little larger than that of the trunk from which they divide, hence the air stream is slowed at these sites, favoring deposition of any particulate matter in it. By the time the air reaches the last and smallest of these branches the total air is ten times greater than that of the original trunk! This continually increasing area of the bronchioles also decreases resistance to air flow, thus favoring ease of ventilation in the lungs. 1
The smallest of the bronchial tubes leads finally into tiny air sacs clustered together in groups that somewhat resemble tiny clusters of grapes. These sacs are called alveoli. The air sacs re move carbon dioxide from the blood and take fresh oxygen into the blood stream through an exchange process in which these substances pass through the walls of the capillaries and air sacs. There is a unique, lung-coating substance known as surfactant, which acts to reduce surface tension and helps keep the alveoli, or air sacs, open.2
The mucous membrane of the bronchial tree, as well as that of the upper respiratory passages, is provided with little hairlike projections known as cilia and there fore functions as a sort of carpeted escalator for removal of inhaled debris and foreign bodies. It must be kept moist for the cilia to function. This is facilitated by the moistening of respired air by the scroll-like lining of the lateral, or side, wall of the nasal cavity.
The blood supply to the lungs is unique in that it is delivered under relatively low pressure so as not to overload the delicate capillary networks but yet have an adequate diffusion of gases. The blood leaving the lungs, laden with oxygen, is then delivered to the left upper chamber, or atrium, of the heart and from there to the left lower chamber, or ventricle, which ejects it into the systemic circulation.
There are ways in which we can all cooperate with this marvelous system given by the Creator for our reception and utilization of the breath of life. One of these is to maintain proper posture. Poor posture increases the work load on these remarkable organs. Respiration is easier if shoulders are held back by the strong back muscles designed for this purpose.
Another way of increasing breathing efficiency is through the development of better breathing habits. Rapid shallow breathing is much less effective in ventilating the lungs than is slow, deep respiration.3
Effects of Tobacco. Tobacco smoke causes much irritation of the lining of the lung surface, as do hashish and marijuana. This in turn results in diminished activity in the small, hairlike cilia, which brings about more prolonged contact of cancer-producing substances in the smoke, including tar, with the bronchi. Tobacco smoke also causes spasm of the bronchial tubes and therefore a marked increase in resistance to air flow both in and, more important, out. The amount of surfactant is diminished, compounding the problem. It used to be thought that inhaled tobacco smoke was so hot that it destroyed alveolar walls. While the hot smoke may damage the lining, or mucosa, of the mouth, it is not all that hot when it reaches the lungs.4 It is now believed that the intense spasm of the blood vessels produced by the nicotine shuts off the blood supply to the alveolar walls, causing them to break down. This process is aggravated by the previously mentioned spasm of the bronchial tubes, which inhibits the outflow of air, and too often results in emphysema, the cause of much invalidism. It can be quite advanced by the age of 40. All in all, it does not pay to abuse our lungs with tobacco smog. Asthma, most often the result of an inherited allergy problem, can also cause emphysema, but why have emphysema if you don't have to?
Effects of Carbon Monoxide. Carbon monoxide has strong affinity for hemoglobin, the gas-transporting medium in the red blood cells that gives them their color. The tobacco smoker of two packages a day automatically puts himself at the equivalent of an 8,000- to 10,000-foot elevation, a needless handicap. But this is nothing compared with the hazards of the unvented gas heater, or stove or floor furnace in a poorly ventilated room. In Van couver, B.C., there were, at one time, about twelve deaths a year from this cause.
In conclusion one might say that the Creator has provided us with a set of lungs designed for a lifetime of trouble-free service. They can only work with what we deliver to them. We are largely responsible for the quality of the air that we breathe. It is up to us to avoid contributing to our own smog problem. Further, by proper posture and breathing habits, we can reduce the effort required to breathe, thus aiding nature in this, perhaps her most vital, work.
REFERENCES
1. P. Dejours, Respiration (New York: Oxford University Press, 1966), pp. 76, 77.
2. E. R. Weibel and ). Gil, Medical World News, Sept. 20, 1968.
3. W. F. Ganong, Review of Medical Physiology, 5th ed., (Los Altos, Calif.: Lange Medical Publications, 1971).
4. J. H. Comroe, "The Physiological Effects of Smoking," Physiology for Physicians, vol. 2, pp. 1-6, 1964.
