The lungs are responsible for taking oxygen from the air we breathe. Oxygen is an essential fuel that our body cells need in order for them to function properly and the lungs pass this vital gas into our blood stream so that it can be transported to where it’s needed by red blood cells. Know more…
Where they are…
In normal human anatomy there are two lungs, one being positioned either side of the breastbone. The left lung is slightly smaller than the right to allow room for the heart, which also fits here in the chest cavity. The medical term relating to the lungs is ‘pulmonary,’ which comes from the Latin ‘pulmo,’ for lung.
What they do…
The lungs are responsible for taking oxygen from the air we breathe. Oxygen is an essential fuel that our body cells need in order for them to function properly and the lungs pass this vital gas into our blood stream so that it can be transported to where it’s needed by red blood cells. As well as taking oxygen from the atmosphere, the lungs remove the waste product carbon dioxide from the blood, expelling it into our surroundings. Our bodies are only able to work within a specific pH range and carbon dioxide falls outside of these normal parameters. Any build-up of this gas in the blood would cause the body to become too acidic to function.
Lung anatomy…
The lungs are divided into five main sections called lobes and are connected to our mouths and noses by the major wind pipe in the throat, which is called the trachea. The trachea branches into two thinner tubes called the left and right main bronchi, which feed into the respective left and right lungs. These bronchi then sub-divide into narrower tubes called bronchioles and at the very end of the bronchioles are bunches of tiny round air sacs called alveoli. Each of these air sacs is covered in a mesh of tiny blood vessels called capillaries, which are connected to a network of arteries and veins that move blood throughout the body. The anatomy of the lungs, therefore, can be seen to resemble the form of a tree in the way that its larger vessels branch off into smaller ones. In turn, the alveoli can be seen as taking the form of small bunches of grapes in the manner that they are grouped around the bronchioles.
How they function…
There are two stages to breathing, or respiration; inhalation (breathing in) and exhalation (breathing out). The inhalation phase brings oxygen into the lungs and the exhalation phase removes the carbon dioxide. Inhalation occurs when the muscle at the base of the lungs, called the diaphragm, contracts. As it does so, it pulls air into the lungs and it is aided in this process by the muscles connected to the rib cage. Exhalation takes place when the diaphragm relaxes and compresses the lungs, pushing the air out of them. During inhalation, air travels down the trachea and along the bronchi and bronchioles until it reaches the alveoli. It is across the alveoli and capillary membrane that oxygen passes into the blood stream and carbon dioxide passes out. On average, a person inhales and exhales around 12 times a minute when at rest, but any form of exertion will require the body to take in more fuel and will produce more waste. In this instance, sensors in the body signal the lungs to breathe more rapidly in order for them to take in more oxygen and to get rid of the extra carbon dioxide.
What can go wrong…
The lungs can be affected by a number of disorders that are bracketed under the term ‘respiratory diseases.’ These disorders may be hereditary, caused by infection, result from trauma or be linked to environmental factors that compromise the quality of the air we breathe. Examples of lung disease include cystic fibrosis, which is a hereditary disorder that causes the lung to produce abnormally thick mucous. This mucous plugs-off the bronchioles and makes breathing very difficult. Asthma is a common immunological lung disease, which is characterised by inflammation and spasm of the lining of the airways. This tightening of the bronchioles results in ‘wheezing,’ as air is attempted to be forced through these narrowed vessels. Tuberculosis and pneumonia are two infectious disease of the lung, with tuberculosis being caused by bacteria. It is life threatening, highly transmissible and one of the most common infectious diseases in the world. Pneumonia is also a serious respiratory condition and is one that is caused by bacteria, viruses or fungi. Traumatic injury to the chest area can also result in damage to either one or both of the lungs. A collapsed lung, known as a pneumothorax, can occur when one or both walls of the lung sac are penetrated. This allows air to enter around the outside of the lung, preventing it from expanding properly during inhalation.
Many lung diseases are caused by, or worsened by, smoking. Examples of serious conditions caused by tobacco products include lung cancer and emphysema. There are many toxic compounds in cigarette smoke which can cause damage to cells in the lungs, resulting in cancerous tumours forming. Emphysema occurs when cigarette smoke causes the alveoli to break down and change shape. The smaller, individual sacs become single larger ones and this reduces the surface area for the exchange of oxygen and carbon dioxide to and from the blood stream. In severe cases of lung disease, a diseased lobe may have to be removed. However, patients can still breathe well using their remaining lobes.
Keeping your lungs healthy…
Without doubt, the best prevention for lung disease is to quit smoking, or if you are a non-smoker, ensuring that you don’t start. Avoiding tobacco smoke also means staying away from an environment where there may be second-hand smoke, as this is just as dangerous as actively smoking. Similarly, if you regularly come into contact with hazardous chemicals, you should ensure that the area is well ventilated to minimise the risk of inhaling toxic fumes. Certain infectious lung diseases, such as influenza (flu) and some forms of pneumonia can be prevented with vaccination, so you should ensure that you are immunised if you are in a high risk group. This includes people over 65 years of age or anyone with an existing chronic health problem, such as heart disease or diabetes.