The lungs are a pair of organs that primarily make up the human respiratory system. They are located in the lower respiratory tract, are enclosed within the pleural sac, and protected by the rib cage. Made up of a total tissue surface that is up to 40 times larger than the outer surface of the body, the two lungs make up one of the largest organs in the body.
Their primary purpose is two-fold: first, to supply oxygen to all parts of the body by extracting it from the atmosphere and moving it into the bloodstream, and second, to expel the carbon dioxide that the body creates as a waste product. This process is called respiration. The lungs also play a secondary role, which is to provide the airflow used to create vocal sounds used in speech.
The lungs are made up of two air-filled organs, each located on either side of the thorax. The right and left lungs are connected to the trachea or the windpipe by several tubular branches called the bronchi. These further spread into smaller branches called the bronchioles, and ultimately, into microscopic branches called the alveoli. The lungs have an approximate total of 300 to 500 million alveoli, which are supported by a thin layer of blood vessels and cells called the interstitium.
The right lung is naturally larger in size than the left lung, as the latter shares the left chest space with the heart. While the right is composed of three lobes, the left has only two. These lobes also further divide themselves into different bronchopulmonary segments and lobules.
Common Lung Problems/Conditions
Lung problems occur when the tissue of the lungs are affected by certain factors, such as smoking, frequent exposure to harmful substances, and infection. Common diseases and conditions that affect the lungs include:
Chronic obstructive pulmonary disease (COPD) – This condition occurs due to some damage to the lungs, which makes it difficult to exhale air. COPD is most commonly caused by smoking, with most affected individuals experiencing severe shortness of breath.
Emphysema – This is a form of COPD in which the damage affects the fragile walls of the alveoli, causing air to become trapped and disrupting the respiration process.
Acute or chronic bronchitis – This refers to the infection of the larger airways of the lungs, specifically the bonchi. Acute cases of bronchitis are commonly caused by viruses, with patients suffering from a sudden onset of cough. Chronic cases, on the other hand, are linked to smoking and are characterized by recurrent cough and difficulty breathing.
Pneumonia – This is a bacterial infection that affects one or both lungs. It is commonly caused by the streptococcus pneumoniae bacteria.
Asthma – Asthma is a long-running condition wherein the bronchi easily becomes inflamed, causing the airways to become narrow or blocked resulting in breathing problems. Asthma attacks are often caused by allergies, air pollution, and viral infections.
Tuberculosis – This is a progressive form of pneumonia caused by the bacteria called mycobacterium tuberculosis. It causes chronic cough, recurrent fevers, and weight loss.
Lung cancer – This condition develops when abnormal cell growths form on any part of the lungs. Most cases of lung cancer are linked to smoking.
Common Pulmonary Procedures and Surgeries
Lung biopsy – This is a procedure in which a small piece of lung tissue is taken from the lungs for diagnostic purposes.
Lung transplant – This is a major procedure in which a diseased lung is removed from the body and replaced with a healthy lung taken from an organ donor.
Lobectomy – This refers to a surgical procedure in which one or more lobes are removed from the lungs. This is often performed when there are malignant cancerous cells in some lobes.
Pneumonectomy – This surgical procedure is used to remove an entire lung, either the left or the right. It is used for the treatment of lung cancer that can no longer be treated with a lobectomy.