Lungs: Intro, Diseases, Causes and Symptoms


Lungs are considered as an essential body part that carries fresh oxygen into the body and eliminates carbon dioxide and other waste gases from the body. The diaphragm tightens and flattens to breathe in (Spahr et al., 2005). While, the lungs and rib cage contract muscles during exhalation (Zhang et al., 2020). The natural process of breathing includes inhaling air through lips and nose to get the required amount of oxygen for body.

Mucous membranes (exist in mouth and nose) moisturize the air and trap the foreign matter particles like dirt and dust. Moreover, the left and right bronchi emerged from the trachea absorb the air that flows through the throat (windpipe). According to Weaver et al. (2020), the lobes (little and thin air sacs) are placed at the end of small airways in cluster form like bunches of balloons.

When a person inhales, these balloons inflate air by expanding the chest cage and in case of exhaling, the “balloons” relax and the air leaves the lungs. Each one of the 300 million alveoli in the lungs is encircled with the tiny blood veins (Pepys et al,.1969). The oxygen present in the blood travels through the walls of the air sacs and transports it to the rest of the body. While, carbon dioxide or other waste gases released from blood into the air sacs and then exhaled.

Main Function of Lungs

Following are the several main functions of lungs;  

  •  It helps in breathing (inhalation and exhalation).
  • During external respiration, lungs act as a pathway to exchange the gases and bloodstream.
  • The lungs are regulating the acidity of the body. 
  • Lungs also perform the process of internal respiration to transfer gases between both the bloodstream and the tissues of the body.

Why do we need lungs to stay alive?

Each organism’s cell requires oxygen to inhale and release carbon dioxide in order to survive. For this, the lungs and respiratory system allow oxygen from the air to enter into the body and permit carbon dioxide to vaporize.

Can we live with one lung?

An individual can survive with one lung because one lung can usually produce adequate oxygen and eliminate enough co2 from the atmosphere. Moreover, the surgeon opens another incision on the side of the body during pneumonectomy (Stern & Frank, 1994)

Role of the lungs in blood circulation

The primary function of the lungs is to take oxygen from the atmospheric air, transport into the bloodstream and then circulates it to the rest of the body. 

Ways to keep lungs healthy

By adopting certain healthy habits, an individual can better maintain the health of the lungs, and keep them working optimally even in older age.

  • Avoid smoking
  • Exercise daily to breathe harder
  • Avoid exposure to pollutants
  • Prevent infections
  • Breathe deeply

Can damaged lungs be cured?

It takes time to recover from lung injury.  The tissue repairs over time, although lung function can take three months to a year or more than that to restore to the original levels.

Do lungs grow back?

An adult human lung can regenerate by the enhancement of pulse rate, enlargement of the surviving left lung, and higher alveolar numbers in a man who had a right-sided pneumonectomy more than 15 years ago.

What is lung disease?

Lung disease refers to the disorder into the organ that allows us to breathe (named lungs). Breathing problems caused by lung disease may prevent the body from getting enough oxygen. 

Common Lung Diseases

Following are the most common lungs disease (reported till date);

  • Asthma, chronic bronchitis, and emphysema
  • Collapse of part or all of the lung (pneumothorax or atelectasis)
  • Swelling and inflammation in the main passages (bronchial tubes) that carry air into the lungs (bronchitis)
  • COPD
  • Lung cancer
  • Lung infection such as influenza and pneumonia
  • Abnormal buildup of fluid in the lungs (pulmonary edema)
  • Sarcoidosis and pulmonary fibrosis

Causes of Lung Diseases

Due to the limited research work till date, experts are not aware about all the possible causes of all types of lung diseases, but some of them are listed as below; 

  • Smoking: Smoke from cigarettes, cigars, and pipes is the main reason of  lung diseases. Avoid smoking and try to make distance from smokers in your surroundings. Ask smokers to smoke in outdoors as it is very dangerous for babies and young children as well.
  • Radon: Radon is a colorless and odorless gas present in many homes that is also recognized as a main cause of lung cancer. A kit is available at many hardware stores to check the level of radon at home in order to reduce its spread as well. 
  • Asbestos: This is a natural mineral fiber that is used in insulation, fireproofing materials, car brakes, and other products. It can give off small fibers that are too small to be seen and can be inhaled. Asbestos harms lung cells, causing lung scarring and lung cancer. It can cause mesothelioma (type of cancer) forms in the tissue covering the lungs and many other organs of the body.
  • Air pollution: Recent studies suggest that some air pollutants like car exhaust may contribute to asthma, COPD, lung cancer, and other lung diseases.

Note: Some diseases that affect the lungs like flu are caused by germs (bacteria, fungi and other viruses).


  • Spahr, J. (2005). This connection of everyone with lungs. University of         California Press.
  • Zhang, D., Li, S., Wang, N., Tan, H. Y., Zhang, Z., & Feng, Y. (2020). The   cross-talk between gut microbiota and lungs in common lung diseases. Frontiers in microbiology, 11, 301.
  • Weaver, C. T., Elson, C. O., Fouser, L. A., & Kolls, J. K. (2013). The Th17 pathway and inflammatory diseases of the intestines, lungs, and skin. Annual Review of Pathology: Mechanisms of Disease, 8, 477-512.
  • Pepys, J. (1969). Hypersensitivity diseases of the lungs due to fungi and organic dusts. Hypersensitivity diseases of the lungs due to fungi and organic dusts.
  • Stern, E. J., & Frank, M. S. (1994). Small-airway diseases of the lungs: findings at expiratory CT. AJR. American journal of roentgenology, 163(1), 37-41.
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