There is a pair of spongy organs, each on either side of the chest. This organ is also responsible for filtering the air we breathe in and providing the required oxygen to the blood for our body metabolisms. This pair of organs is called Lungs. Lungs are the largest organs in the body, and they work with the respiratory system that permits one to take in fresh air, get rid of stale air and also talk.
Lungs are located on both sides of the chest in the ribs above the stomach, liver, kidneys and resting on the diaphragm. The right Lung is divided into three lobes – superior lobe, middle lobe and inferior lobe by a horizontal fissure and an oblique fissure while the left Lung is divided into superior and inferior lobes only by an oblique fissure. The left Lung is smaller than the right one because of the heart. It also has an indentation known as the cardiac notch that covers the apex of the heart. The Lungs have a rounded tip known as apex and a concave bottom known as base. The entire of the Lungs is covered by a thin layer of tissue known as pleura, double-layered serous membrane. The outer layer is known as parietal pleura and the inner layer is known as visceral pleura. Between the layers there is a hollow space known as pleural cavity which the Lungs use to expand while inhaling. The pleura also secrete a fluid known as serous fluid which helps the Lungs to expand and contract without any irritation or friction during inhalation and exhalation respectively. The entire of the inner surface of the Lungs would cover an area of 80 to 100 sq. metres if stretched out flat.
The main function of the Lungs is respiration where the Lungs remove carbon dioxide from the air we breathe in and let it out while exhaling and retain the oxygen from the air. The Lungs also supply oxygen to the blood cells which they can use for various body metabolisms.
Lung diseases are among the most widely affected diseases in the world. The major reasons of the Lung diseases are smoking, infections and genetics. Some of the major Lung diseases are:
Asthma: This disease is caused mainly due to the inflammation of the respiratory tubes which create occasional spasm that leads to shortage of breath and the person starts panting.
Chronic obstructive pulmonary disease (COPD): It is the Lung disease in which the Lung suffers from the inability to exhale leading to difficulty in breathing.
Tuberculosis: This is a bacterial infection caused by a bacterium known as Mycobacterium tuberculosis.
Lung Cancer: This is one of the most hazardous Lung diseases and is developed in any part of the Lungs.
Pleurisy: One suffering from pleurisy feels pain while inhaling which is due to the inflammation of the pleura.
The first filtering of the air that we inhale is done at nose itself where most of the irritants are prevented from entering inside. Few of the other irritants that managed to enter towards the Lungs are trapped by the mucus secreted in the thin layer of the respiratory tubes and the hair like microscopic filaments known as cilia moves the mucus towards the mouth. Another mechanism that protects Lungs is coughing. It occurs when there are irritants along the inner linings of the respiratory tubes and it thus helps in moving the mucus with irritants out. The most common protective measure of Lungs to protect themselves is bronchospasm where the muscle bands around the airways are tightened narrowing down the airways. This mechanism happens only when the Lungs are irritated and it helps in keeping the irritants out.