Coughing is due to irritation of the airways - due to bronchitis, the common cold, or smoking. It causes rapid exhalation. Hiccups are due to an involuntary contraction of muscles is the diaphragm and hoarseness often is due to overexertion.
is a perfectly natural reaction to various irritants in the airways and therefore it is not a disease in itself; it is more a symptom of a problem located somewhere in our airways.
Coughing is a kind of airway preventive reflex to avoid making our lung capacity reduced on account of pollution which in the long run would result in cell anaemia. A sustained cough is often a sign that the immune system works at protecting us from disease.
Located in the trachea, bronchi, pleura, and the mucosa of the large bronchi are nerve receptors that are very sensitive to irritation. If they come into contact with some kind of particle, a reflex is triggered causing the well-known, violent, jerky expirations from the lungs supposed to remove phlegm and other irritants.
Coughing can be done voluntarily when purposely coughing to dissolve phlegm and other things irritating the airways. It is more difficult to suppress coughing. Most people know the feeling of being in an audience at some kind of cultural performance with a cough that only gets worse if trying to suppress it.
The cough itself consists of a deep inspiration, the glottis closes, and the air in the lungs and airways is set under pressure as the diaphragma contracts - then the glottis opens, and the air is violently emitted (expiration). Simultaneously, the muscles contract causing the airways to constrict. This creates the violent emission of air pressing phlegm and foreign bodies up into the pharynx where it can be spat out through the mouth.
Coughing is often caused by a mucosal irritation in the airways, possibly because of an inflammation caused by microorganisms - also called catarrh. There might be an inflammation with a lot of mucus where the coughing serves to remove the mucus from the airways - this is called a loose and humid cough. This cough serves a purpose just like the cough that removes irritants from the airways.
The dry cough that is not accompanied by phlegm, however, does not have any purpose and can actually cause damage in the long run by maintainig the irritative condition in the mucosa.
There have been examples where otherwise healthy women non-smokers with chronic cough coupled with slight throat inflammation have experienced relief from their symptoms by taking iron supplements for a few months.
Coughing can also be a symptom of a more serious disease, e.g. a functional disturbance in the thyroid gland - causing croup - or tuberculosis. Moreover, tumours and swollen lymph nodes also can put pressure on sensitive areas in the airways. Therefore, if you have bloody sputum or experience an extreme fatigue you should be examined by a doctor. If you suffer from croup for a long period of time (weeks) you should be examined for possible thyroid gland disturbances.
If your throat, airways, pharynx, or larynx is attacked by bacteria or vira, the coughing reflex will set in. Bronchitis arise if bacteria and vira attack the upper respiratory passages and causes mucus to be created by the bronchial mucosa. This often leads to a painful cough. Some people experience a transcient cough when eating cold things like ice cream or very cold drinks.