Your Lungs are Living Air Purifier Filters Within Your Body
Think of your lungs as being a remarkably complex bio-mechanical air exchanger or living air purifier. Like the chemical vapor absorbing materials found in the best air purifiers (such as activated carbon) your lungs are “designed” or “evolved” (which ever you prefer to believe) to filter out the smallest of gas particles; in fact, your life depends on your lungs’ capacity to efficiently extract the tiniest of gaseous molecules of diatomic oxygen from air and they do it about 15 to 25 times per minute without any conscious direction on our part.
The respiratory system is ultimately associated with the circulatory system such that over 9,000 liters of air meets with 10,000 liters of blood in the lungs every day. That blood is pumped by the heart to the lungs via the pulmonary artery. The oxygen molecules from the inhaled air diffuse into the tiny capillaries which pass between and around the millions of air sacs or Alveoli inside the lungs. It has been estimated that if laid end to end the capillaries in the lungs would stretch for almost 1,000 miles. For the most efficient gaseous exchange within the lungs the internal surface area of the lungs is estimated to exceed that of a tennis court. Most of this surface area is from these millions of Alveoli. The Aleveoli share the same very thin cell walls as the capillaries so oxygen does not have far to go before it enters the blood. Likewise, poisonous carbon dioxide gas created by metabolic processes throughout the body easily diffuses out of the blood and is exhaled from the lungs.
As oxygen enters the capillaries it is bound by Hemoglobin which is an iron-containing metallo-protein found in the Red Blood Cells. At any given moment we have about 30,000,000,000,000 (that’s 30 TRILLION!) Red Blood Cells circulating throughout our body, and they contain a total of about 3.5 grams of Fe, almost five times the total amount found in other cell matter. The iron atoms at the center of the Heme units in Hemoglobin is the reason why Hemoglobin can bind and transport oxygen. The oxygen carrying Red Blood Cells are then pumped back to the heart via the pulmonary vein and then circulated back to the cells throughout the body such as muscle cells where they unload their oxygen to be used for metabolic processes like cellular respiration.
The rate at which the lungs exchange life giving oxygen for the poisonous carbon dioxide made by our cells is automatically regulated by the autonomic nervous system which gets feedback and regulates breathing according to our physical activity or ambient oxygen concentration. Because of this control system breathing is not an action we can consciously cease to perform for very long. So strong is the automatic reflex in control of our lungs’ function that we would only be able to willingly hold our breath for so long before our conscious will would be overridden by the autonomic will to increase breathing in response to falling oxygenconcentrations in the blood. However, the proper functioning of the lungs is important to the body for not just gas exchange. The lungs also function to regulate the percent of hydrogen ions (or pH) of the blood. They are also important in filtering out small blood clots in the veins and the lungs’ spongy texture makes them an important protective cushion for the heart.
Some of the most common inhalation hazards which can damage your lungs include: pollen, moldspores, bacteria, tobacco smoke, formaldehyde, methylene chloride, hydrogen cyanide, ammonia, particles, hydrocarbons, carbon tetrachloride, benzene, ozone, and bioaerosols.
Unfortunately, the lungs filter out more than just oxygen. The air we breathe while at home, in the car, at work, or at play is often times not very pure, hence our lungs are frequently exposed to damaging particulates and vapors both manmade and natural. Like home air purifier filters the lungs accumulate particles in direct proportion to the amount of air processed and concentration of pollutants. Unfortunately, one important difference between your lungs and home air purifiers is that your lungs don’t have removable HEPA filters you can simply change when they get dirty! Thus particulates and resultant cellular damage tend to accumulate over time so it’s important to minimize your exposure to ambient air pollutants through source control, ventilation, and air cleaning. Fortunately, there are certain built in biological mechanisms involving over three dozen distinct types of lung cells through which the respiratory system attempts to remove particulate contaminants and control cellular damage in the lungs and elsewhere.
One mechanism for removing inhaled particles from the lungs involves cilia which are tiny moving hair like structures that “sweep” the airways clean when possible. However, tiny sub 0.4 micron particles which often account for over 90% of inhaled air pollutants are especially difficult to remove because they travel so deeply into the nooks and crannies of the lungs’ alveoli, or air sacs, and have also been proven to sometimes traverse cell walls and pass into the blood stream via the many small alveolar capillaries. Other particles like Asbestos Fibers can permanently lodge inside the tiny airways or bronchioles of the lungs causing Asbestosis, Mesothelioma, or Lung Cancer.