Lungs are remarkable organs that continuously achieve amazing feats; which they do so well that we take them for granted; except when their function is diminished. It all happens in a space inside your chest; divided in two and reduced by the presence of the heart; the great vessels and the esophagus. With Supreme Court Justice Ruth Bader Ginsburg having recently returned to the court after surgery for lung cancer; I have been asked a lot of questions about the lungs; as I am a professor of anatomy.
Many lung cancers are not operable;  but to treat some types of lung disease; such as early stages of lung cancer;  a surgical treatment called a lobectomy may performed. In this operation, a lobe of a lung (your right lung has three lobes, your left lung has two) is removed. Afterward, the other lobes expand to adapt and compensate for the missing tissue, allowing the lungs to work as well or better than they did before.

The function of the respiratory system

In addition to highly efficient organs; the lungs are beautifully complex in their structure. I can not help but wonder: If we appreciated them more; would more proactive in taking care of them? The primary function of the respiratory system is to bring oxygen into our lungs. There it is exchanged for a waste product, carbon dioxide; which is then removed from the body. Several weeks following conception, the work of the lungs is performed by the placenta.
A structure outside our fetal bodies where our blood exchanges carbon dioxide and oxygen with the maternal blood of the uterus. Before birth, we just practice respiratory movements; moving amniotic fluid instead of air in and out of the lungs. Within seconds after the umbilical cord is cut, a buildup of carbon dioxide causes newborns to gasp for breath to exchange it for oxygen, an activity that will continue until our death.
The average person breathes some 13 million cubic feet of air during their lifetime. During quiet activity; such as bed rest or sitting, we take eight to 16 breaths per minute; each breath inhaling about a pint of air containing 21 percent oxygen and a small amount of carbon dioxide for about two seconds. Then for three seconds; they exhale the same amount of air, but it now contains 16 percent oxygen and a 100-fold increase in carbon dioxide.

Immense blood supply

In other words, you spend about 40 % of your life drawing air in; 60 % of your life expelling it. The capillaries of the lung receive immense blood supply; equal to that distributed to all other parts of the entire body. The alveoli expand and contract 15,000 times a day. During the activity, the rate of respiration doubles and in extreme activities triples and the amount of air reaching the alveoli increases three to five times.
Breathing deeper and faster uses lung capacity that is held in reserve while at rest. Stress can also result in deeper and faster respiration. While the lungs were a pristine pink at birth; our lungs gradually darken to a gray and mottled appearance due to these carbon particles, much of which remains in place, usually with no detrimental effect. Larger, irritating particles are commonly “blasted” away by reflexive coughing and sneezing.

This air conditioning system is compromised in smokers; whose airways lose cilia and their directional coordination, and so must revert to coughing as a major means of pollutant removal. Smokers’ lungs darken faster; becoming more mottled, and take on an orange tone due to nicotine and brown tars.

Prolonged exposure to these carcinogens causes chronic bronchitis, emphysema, and cancer in many parts of the body; but especially around airways just inside the entrance to the lungs. In emphysema, the alveolar structure of the lungs collapses; especially in the upper lung, making it difficult to fully exhale.