The respiratory system is the first part of the anatomy mentioned in the Bible. According to the scriptures, Adam was a formed organism made from material from the earth, but he was not living until God breathed into his nostrils. The respiratory system begins in the nose and mouth and also includes the pharynx, epiglottis, trachea, larynx, bronchi and lungs. As the bronchi enter the lungs, the tubes branch out into smaller and smaller tubes called bronchioles and finally end in small, elastic air sacs called alveoli where the oxygen/carbon dioxide gas exchange takes place. The right lung has ten segments and the left has eight. These segments are self-contained units, which is very useful when a disease or injury requires surgical removal of part of a lung without any damage to the other segments.
Gas exchange requires certain criteria to be in place. For one thing, the greater the surface area available for gases to cross, the better. Another factor is that the width of the barrier for the gas to cross should be very small. God, of course, took these things into account. If one were to spread out all the inside surfaces of the lungs side by side, the average adult’s lungs would have the surface area of a tennis court. Blood in the tiny capillaries (blood vessels) in the lungs is separated from the air in the lungs by tissue less than one thousandth of a millimeter in places. That is amazingly thin.
So you breathe in and breathe out, and that is all there is to it, right? There is much more to it than that. First of all, the air you breathe presents problems to the respiratory tract. The air inside needs to be both at body temperature and very moist, but outside air temperature and humidity varies. The outside air is filled with dust, debris, and germs, all of which should not get into the alveoli. Not surprisingly, our bodies were designed to deal with these problems. From the nose to the lungs, the passageways are lined with mucous-producing tissue, so by the time the air reaches the lungs, it is warmed and moistened. We also have several filtration systems in place. The sticky mucus acts as a trap for particles, and once trapped, upward/outward movement of cilia (tiny hair-like projections on cells lining the respiratory tract) removes the debris. In the nose, the cilia move the debris downward. The debris is moved to the throat where it is then swallowed and destroyed in the stomach.
Since part of the throat is used for both eating and breathing, there is a potential traffic problem. We know what happens if air gets to the stomach—unpleasant, but generally harmless. However, food or fluids do not belong in the lungs. The epiglottis is a flap of cartilage that covers the entry to the lungs via the larynx when you swallow. Otherwise the epiglottis remains in an upright position at rest, allowing air to pass freely into the lungs. Occasionally we try to do both at the same time and end up choking. A drop of water is all it takes to set off a gagging cough, but it is not life threatening. An object such as a piece of food in the larynx, or a lungful of water, as in a drowning, are life threatening events, because they prevent air from filling the alveoli, and therefore gas exchange cannot take place.
The larynx is commonly known as the voice box. It contains three folds (vocal cords) that vibrate in the air stream, producing sounds. The particular sound of your voice is a combination of the size and shape of your vocal folds, pharynx (upper throat), nasal passages, and mouth.
The act of breathing is essentially caused by changes in pressure. The lungs are surrounded by muscles. Your diaphragm, the most important respiratory muscle, is located at the base of the chest cavity. There are muscles between the ribs as well that play an important part in breathing. The muscles cause the chest cavity to increase in size or expand. This causes the pressure in the lungs to decrease, which in turn, causes outside air to be sucked into the lungs. This is called inspiration, or breathing in. When you relax your muscles, the chest cavity becomes contracted. Pressure in the lungs increases and air is expelled. This is called expiration, or breathing out. The more muscles are used to breathe, the deeper a breath you can take.
Premature babies (less than two pounds [0.9 kg] or less than 37 weeks gestation) often have respiratory problems. The main cause is that their immature lungs have not made any or enough of a substance called surfactant. Surfactant is a soap-like material produced in the lungs. Think of a rubber balloon. Sometimes, especially if too warm or too old, an uninflated balloon sticks to itself and cannot expand. If a little liquid soap is poured into the balloon, the slippery surfaces prevent the sides from sticking and allow the balloon to expand. This is what happens in the lungs. The surfaces within the lungs must not only be flexible but slide over each other well. Without surfactant, the premature baby’s tiny lungs either do not expand initially or collapse on expiration. In adults, a similar situation can occur with inhalation of water, fumes, or other substances. Fortunately, in both babies and adults, this problem can be treated in most cases.
Though the body is designed to purify the air we breathe, there are those who purposely engage in activities that the body cannot easily handle. Most people, nonsmokers and smokers alike, are aware that smoking is very harmful to health. Inhalation of cigarette smoke causes a large amount of poisonous gases and particles to enter the respiratory system. The gases can pass over into the blood stream just like oxygen does. The particles cannot be moved out of the lungs easily and damage to the delicate cilia occurs. Eventually, the amazingly thin membranes in the alveoli become coated with a gooey, black substance, and gas exchange becomes difficult or impossible. Cigarette smoke contains at least 43 different cancer-causing chemicals and is responsible for 87 percent of lung cancers. Smoking also causes heart disease and stroke and a variety of other problems, which is why 440,000 Americans die each year from diseases caused by smoking.
It is clear that God designed our complex respiratory systems to be both hard working and delicate. When we choose not to follow the laws of health, our breath fails. Ellen White knew that: “The health of the entire system depends upon the healthy action of the respiratory organs;” because “the strength of the system is, in a great degree, dependent upon the amount of pure, fresh air breathed. If the lungs are restricted, the quantity of oxygen received into them is also limited, the blood becomes vitiated, and disease follows.” Healthful Living, 171. God’s laws are in place for a very good reason. Without them, life fails.
“The Spirit of God has made me, and the breath of the Almighty gives me life.” Job 33:4, NASB.
Sheryle Beaudry, a certified teletriage nurse, writes from Estacada, Oregon where she lives with her husband and twin daughters. She may be contacted by e-mail at beaudry@cascadeaccess.com.