Lungs

The lungs are the body's respiratory organs. Located in the chest and surrounded by the ribs, they enable us to absorb oxygen from inhaled air and remove waste products through exhaled air.

Anatomy of the lungs

Humans have two lungs: a left lung and a right lung. There are some anatomical differences between them. The left lung is slightly smaller than the right because the heart is largely located on the left side. The left lung consists of two lobes, while the right lung has three. As shown in the image, the lungs resemble an upside-down tree inside a bag. From top to bottom, there is first the trachea, which acts as the "trunk." It carries inhaled air from the nasal or oral cavity to the lungs. At the end of the trachea are the bronchi, the branches that form the entrance to the lungs. Once inside the lungs, the bronchi branch approximately ten more times. In addition to distributing oxygen, the bronchi also filter inhaled dust particles and bacteria. At the ends of these branches lie the alveoli, or air sacs. These are tiny cell sacs where gas exchange occurs between the inhaled air and waste products, primarily carbon dioxide (CO₂), in the blood.

Function of the lungs

The respiratory system consists of the nasal cavity, oral cavity, pharynx, trachea, bronchi, and alveoli. Together, they supply the body with oxygen (O₂) while removing carbon dioxide from the blood. Inhaled air contains only 20% oxygen and 79% nitrogen, an inert gas. In healthy lungs, gas exchange occurs approximately 15 to 20 times per minute. This means the lungs process about 0.5 litres of inhaled air every 3 to 4 seconds. The millions of alveoli have thin, elastic walls, and gas exchange takes place through a network of tiny blood vessels surrounding them.

Respiratory centre

The brain contains the respiratory centre, which ensures that carbon dioxide and oxygen levels in the body remain constant. This process is automatic. When the carbon dioxide level in the alveoli reaches a certain threshold, a nerve impulse is sent to the respiratory centre. This centre then immediately commands the respiratory system to inhale using the respiratory muscles. The resulting gas exchange reduces the carbon dioxide level in the alveoli. This cycle repeats whenever carbon dioxide levels rise again.

Diseases of the lungs

Problems with the lungs or airways can have serious consequences, as proper lung function is vital. A common lung disease is asthma, in which inflammation causes breathing difficulties. Another common condition is COPD, an umbrella term for chronic lung diseases that damage the lungs. Two key conditions under this term are bronchitis and emphysema. In pneumonia, the lower airways, particularly the alveoli and surrounding tissue, become inflamed. The body attempts to clear the bacteria or virus causing the issue, which can lead to mucus buildup. This, combined with irritation, results in coughing and shortness of breath. A pulmonary embolism is a blockage in the pulmonary artery, reducing oxygen uptake in the lung. This is usually caused by a blood clot that formed elsewhere in the body and travelled through the bloodstream.

Treatment of lung problems

Lung problems can be treated by various specialists. The first point of contact is usually a GP. For mild lung issues, the GP can provide advice or prescribe medication. In more complex cases, the GP may refer patients to a pulmonologist or a respiratory physiotherapist.