Human Anatomy – Lungs
- Human Anatomy – Tonsils
- Human Anatomy – Teeth
- Human Anatomy – Stomach
- Human Anatomy – Tongue
- Human Anatomy – Esophagus
- Human Anatomy – Liver
- Human Anatomy – Gallbladder
- Human Anatomy – Pancreas
- Human Anatomy – Spleen
- Human Anatomy – Appendix
- Human Anatomy – Intestines
- Human Anatomy – Colon
- Human Anatomy – Abdomen
- Human Anatomy – Penis
- Human Anatomy – Bladder
- Human Anatomy – Kidneys
- Human Anatomy – Prostate
- Human Anatomy – Vagina
- Human Anatomy – Heart
- Human Anatomy – Skin
- Human Anatomy – Aorta
- Human Anatomy – Thyroid
- Human Anatomy – Lungs
- Human Anatomy – Brain
- Human Anatomy – Eyes
- Human Anatomy – Ears
- Human Anatomy – Sinuses
- Human Anatomy – Trachea
- Human Anatomy – Blood
- Human Anatomy – Rotator Cuff
- Human Anatomy – Shoulder
- Human Anatomy – Feet
- Human Anatomy – Hair
- Human Anatomy – Achilles Tendon
No human being could survive without breathing air. To be able to do that, everyone is equipped from birth with two organs known as the lungs.
Air travels to each lungs through the trachea or windpipe, and then through a pair of large tubes called the bronchi. The bronchus goes inside the lung, where it branches out into small bronchioles. At the tips of the bronchiole are branches of the even tinier alveoli, which are practically microscopic bags of air. There are millions of these, connected to capillaries in the lungs.
Every time you breathe in or inhale, whenever air passes through your nose or mouth, tiny hairs known as cilia trap dust from it. These hairs line the nostrils and along with mucus, the windpipe. After traveling through the bronchi and the bronchioles, the air ultimately winds up in the alveoli. The wall of every alveolus then filters the air, such that only oxygen enters the capillaries, where red blood cells transport it to the heart. The heart pumps this “oxygenated” blood to all the cells in the body.
In exchange for oxygen, the cells in the body unload their waste (carbon dioxide) on the red blood cells, which then return to the lungs. From the capillaries, the red blood cells empty the carbon dioxide into the alveoli. The carbon dioxide-filled air then rushes out of the alveoli; through the bronchioles, bronchi, windpipe; and finally out of the nose or mouth. All these happen whenever you breathe out or exhale.
Your lungs are not symmetrical; the right lung is slightly larger than the other. This arrangement allows the heart to fit in the left side of the chest.
Right beneath the lungs is a muscle called the diaphragm. It contracts whenever you breathe, lifting your ribs while pushing down the organs below the expanding lungs. The opposite happens when you exhale: The diaphragm relaxes along with the muscles between the ribs.
Lung diseases and conditions
In 2003, a phenomenon called severe acute respiratory syndrome (SARS) swept the world. The pandemic has since been controlled, but not before it made international headlines. SARS is a kind of pneumonia, an umbrella term for an infection in the lungs.
Pneumonia is often caused by bacteria, such as Streptococcus pneumonia. It may even be caused by fungi: as in Coccidioidomycosis, by the fungus Coccidioides, and Histoplasmosis, by the fungus Histoplasma capsulatum.
Sometimes, pneumonia may be preceded by the highly contagious disease known as influenza. Any of several viruses cause this disease, known popularly as the flu.
Pneumonia becomes an especially urgent condition when it occurs with tuberculosis, one of the world’s deadliest diseases. Caused by the bacteria Mycobacterium tuberculosis, this disease is characterized as a slow-progressing pneumonia accompanied by chronic cough, fever, weight loss, and night sweats.
Lung cancer is also one of the deadliest diseases in the world. According to the World Health Organization, this type of cancer claims more than a million lives every year. Smoking is the number one cause of this cancer.
Smoking leads to a variety of lung-related conditions other than cancer. It can inflict damage on the lungs, causing shortness of breath in a condition called chronic obstructive pulmonary disease (COPD). Emphysema is a kind of COPD in which the alveolus wall becomes damaged, locking in air and interfering with breathing.
Smoking can also cause chronic bronchitis, an inflammation of the lining of the bronchi. However, viruses usually cause acute bronchitis. Either way, bronchitis manifests itself with frequent, repeated coughing.
Bronchitis shares similarities with bronchiectasis, a lung condition that occurs when part of the bronchi becomes irreversibly dilated. Someone who has this condition coughs a hefty amount of mucus.
Asthma is when you have chronically inflamed bronchi, making breathing difficult and causing spasms. Its symptoms flare up once you get exposed to triggers, such as allergies, viruses, dust, and polluted air.
A bacterium called the Bordetella pertussis can infect the bronchi. The resultant condition is called pertussis, more commonly known as whooping cough. Pertussis can be prevented with booster vaccination though.
It is not only the bronchus that is vulnerable to debilitating conditions. The interstitium or the walls among alveoli can also become diseased. If left untreated, interstitial lung disease worsens into pulmonary fibrosis or scarring of the alveoli walls. Cystic fibrosis is what you call the hereditary condition in which excess mucus lingers in the bronchi, leading to recurring bouts of pneumonia and bronchitis.
Even the pleural space – the limited void between the lungs and the lining of the chest – is not impervious to conditions. When fluid accumulates in this space, you are said to have pleural effusion. If air fills up this space instead, you have pneumothorax.
In hindsight, all parts of the lungs can be easily inflamed. Sarcoidosis refers to pockets of inflammation throughout the lungs. Pleurisy refers to the inflammation of the pleura or lung wall.
Pulmonary embolism is an oft-mentioned cause of pleurisy. This condition happens when the heart pumps a blood clot into the lungs. The clot usually journeyed to the heart from elsewhere in the body, e.g. the legs.
Sometimes, the arteries connecting the lungs to the heart may suffer from high blood pressure. Such condition is known as idiopathic pulmonary arterial hypertension.
Several factors other than lung conditions can cause you to have difficulty breathing. There are cases when obesity interferes with this activity, a condition termed obesity hypoventilation syndrome. If not obesity, dust can make breathing difficult, by triggering an allergic reaction called hypersensitivity pneumonitis.
Severe illness can inure the lungs all of a sudden. This condition, known in medical parlance as acute respiratory distress syndrome, requires life support.
On top of all these conditions, there are rarer lung conditions in existence. An example would be mesothelioma, a cancer usually caused by exposure to asbestos. Another would be lymphangioleiomyomatosis, wherein cysts build up around the lungs.
Treating lung conditions
Healthy lifestyle advocates could not overemphasize enough the virtues of not smoking. Quit smoking or don’t even start. It would also save your life if you stay away from second-hand smoke, which is far deadlier.
On the whole, lungs are averse to many gaseous substances. In this thought, healthy lifestyle experts recommend wearing a mask when handling even household chemicals.
Finally, healthy lifestyle experts advise exercising. Aerobic activity strengthens the muscles of the lungs.
If your lung is too diseased to salvage however, the doctor may have no choice but to surgically remove it. This is usually the solution if you have serious cases of pulmonary fibrosis, COPD and pulmonary hypertension. A lung can be transplanted from a donor to replace the removed organ.
Lung cancer is usually treated with lung resection or the surgical removal of a part of the lung. But surgery is not enough. Lung resectioning is always paired with chemotherapy and radiotherapy.
Doctors usually drain fluid or air from the lungs via a tube, in a procedure known as thoracostomy, or a needle, in pleurocentesis.
Medicines work effectively, insofar as they correspond to conditions they are indicated for. Antibiotics are for conditions of bacterial origin, while antiviral medicines are for those of viral nature, such as influenza. However, the latter cannot effectively treat viral or acute bronchitis.
COPD and asthma sufferers may use oral or inhalable corticosteroids to alleviate their symptoms. Alternatively, they can use bronchodilators to widen the bronchi.
As for individuals with pulmonary hypertension, vasodilators are in order. These are usually taken intravenously.
Mechanical ventilators are recommended for those who have serious trouble breathing. These are machines that pump air through a tube introduced into the patient’s mouth or neck. Likewise, the patient can receive air via continuous positive airway pressure, or a mask connected to a machine.
Tests for lung conditions
Before diagnosing lung conditions, doctors often ask for a simple X-ray. An X-ray should be able to spot air or fluid in the lung or chest. It can also detect masses and foreign bodies therein.
Otherwise, the doctor may request for multiple examinations called pulmonary function tests (PFTs). These tests measure, among others, the capacity of the lung and its ability to oxygenate the blood.
Your sputum can be used in several lung tests. One test is sputum culture, used to diagnose pneumonias and bronchitis. Another is sputum cytology, used to identify lung cancer.
If all else fails, the doctor may call for an endoscope to be inserted into the bronchi, a test called bronchoscopy. The endoscope used may either be flexible or rigid. While it is less effective than rigid bronchoscopy, flexible bronchoscopy does not need general anesthesia.