As lungs are indispensable organs of our body, knowing what are lung diseases can help us keep our health in check. We all inhale and exhale around twenty times per minute without thinking. This amazing phenomenon happens due to the functions of the respiratory system. The lungs can be considered as the main organ in the respiratory system. They are complex organs with many parts in each of them. In this article, we are going to look at the anatomy of the lung, how it functions, how it gets affected in an injury or in a disease and the newest intervention in biomedical engineering to overcome the problems.
Anatomy of lungs
The lungs are spongy tissued organs, filling the chest cavity. They have a cone shape, and their main task is to exchange the gases between the body and the external environment. The superior end of the lungs, which makes a narrowed tip is known as the apex, and the inferior end, which is above the diaphragm is called as the base.Each of the lungs is covered with a thin membrane called pleura that has two layers. The inner layer is next to the lung, and the outer layer is medial to the wall of the thorax cavity. In between the two layers there is a serous fluid which helps to protect the lungs from friction during breathing. Though there are two lungs in our body, they are not identical as the right lung has three lobes – the superior, middle, and inferior while the left lung only has two lobes- superior and inferior to give space to the heart. The tidal volume (the normal inhale and exhale volume per one respiratory cycle) of the lung is about 500ml.
Functioning of lungs
The lungs receive air through a process of changing pressure. When inhaling, the diaphragm and the intercostal muscle, which are around the lungs, expand, making the volume of the thorax cavity larger and a low pressure hole. Then, the air comes from outside to inside. When exhaling, the inverse of this happens. The muscles contract, reducing the thorax cavity volume and making a high-pressure region. Then, the air moves from inside to outside.
The trachea (windpipe) takes the air into the lungs through its branches called bronchi. Furthermore, they divide into smaller branches called bronchioles and finally end up making a cluster of air sacs called alveoli. These alveoli are the main functional units in the lungs. Inside these sacs, the oxygen concentration is higher than that of the human blood, so oxygen diffuses across the alveolar membrane into the pulmonary capillary. Those oxygen molecules make bonds with hemoglobin in the blood. The blood in the pulmonary capillaries contains more carbon dioxide. Hence, CO2 releases from the capillaries and diffuses into the alveolus.
Each of the lungs is connected to the immune system through lymph nodes. These lymphatic vessels help to take bacteria, viruses and cancer cells away from our lungs.
What are Lung Diseases and What are their effects
We can identify many lung diseases as they are the most common type of medical issues in the world. Most of the lung diseases arise due to infections, genetic problems and smoking. These diseases and poor functioning issues can be categorized by the part that the disease affects. In this section, we are going to look at some of the common diseases and the effects taken place.
The first category is the diseases affecting the airways: the trachea, the bronchus, and bronchioles. Asthma, COPD (chronic obstructive pulmonary disease) and Chronic Bronchitis are the common diseases we all know which affect the airways. Wheezing and shortness of breathing are happening in asthma condition as the airways become thinner from inside. COPD and Chronic Bronchitis make difficulties in breathing and cough.
The second type is Alveoli affecting diseases such as Pneumonia, Tuberculosis, common lung cancers and ARDS (Acute Respiratory Distress Syndrome). Most of these conditions are fatal if proper treatments are not carried out. Bacteria and viruses infect pneumonia and Tuberculosis. In these situations alveolus decay due to a bacterial infection. In many occasions, lungcancers grow out of smoking and some other causes may also be reasons for lung cancers. Many functional disorders such as wheezing, coughing and difficulties in breathing may happen due to cancers.
The interstitium is the thin, delicate lining between the alveoli. Tiny blood vessels run through the interstitium and allow gas exchange between the alveoli and the blood. ILD (Interstitial Lung Disease) is not a name used for a particular disease, but a collection of diseases that affects the interstitium. Sarcoidosis, idiopathic pulmonary fibrosis, and autoimmune disease are among the types of ILD. Pneumonia can also affect the interstitium.
Some blood vessel problems may also end up with lung problems as pulmonary arteries go into the lungs for gas exchange. Pulmonary embolism: a condition where a blood clot breaks off in the pulmonary artery and Pulmonary hypertension (High blood pressure) cause low oxygen level in the blood and difficulties in breathing.
The Pleura can also be affected due to someother diseases or disorders. Pleural effusion is a situation where a fluid collects between the chest wall and the lungs, which leads to difficulties in breathing. It can be caused by a heart failure. Pneumothorax is another condition where instead of a fluid air enters between the lungs and the chest wall collapsing the lung. There are some other rare issues on chest walls, which leads to difficulties in breathing such as neuromuscular disorders and Obesity hypoventilation syndrome.
Biomedical engineering inventions to cure lung diseases
Nowadays biomedical engineering is at a stage where many lung issues can be cured with biomedical engineering inventions.
Asthma is normally treated using inhalers and medicines, but more advanced and quick method called Doctors use bronchial Thermoplasty as the newest treatment method. In this method, a flexible tube is inserted into the lungs through the mouth of the patient. Then a small wire is passed through the tube to the places where the airway is thinner. Through the wire, a radio wave is emitted and this radio wave heats the airway making it wider. This is done under an anesthetic condition and it is a painless method.
In COPD and bronchitis a same type method mentioned above is used but in a different manner. In this case a tiny flexible coil is passed through the tube and permanently placed inside the airways to restoring the elasticity of the airway. The lungflute isanother new simple therapy for COPD. When the patient blows the flute, sound waves travel down the airways and mobilize mucus.
The patients who cannot have surgery for the primary stage lung cancers can now have a new radiation therapy method called SBRT (Stereotactic Body Radiation Therapy). In this method, a high radiation dose is given to the patient with extreme accuracy. Its quickness can be identified as the conventional radiation method has to be used for patients over 5 -6 weeks while this method only spends 3-4 days for the full treatment. There are also non-invasive GPS systems to track down the lung cancers.
Lungs are complex organs that perform a special task and important in the human body. They help to exchange the gases between the body and the external environment. They can be easily affected by many things such as bacteria, viruses, dust, genetic problems and smoking. There are five places that are affected during a lung disease. They are airways, Alveoli, Interstitium, blood vessels, Pleura and the chest wall. The early days traditional methods like antibiotics and other medical therapies were used, but in nowadays with the intervention of biomedicalengineering,more technologically developed easier methods, are used to treat the lung issues.
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