A is a sudden, often repetitive,
Spasm odic contraction of the
Thoracic Cavity , resulting in violent release of air from the
Lung s, and usually accompanied by a distinctive sound. Coughing is an action the body takes to get rid of substances that are irritating the air passages. A cough is usually initiated to clear a buildup of
Phlegm in the
Trachea ; air may move through this passage at up to 480
Km/h (300
Mph ) during a contraction. Coughing can also be triggered by a
Bolus of food going down the trachea instead of the
Esophagus , due to a failure of the
Epiglottis , although this may result in
Choking instead. Frequent or
Chronic coughing usually indicates the presence of a
Disease . Provided the patient is a non-smoker and has a normal chest
X-ray , the cause of chronic cough in 93% of all patients is due to
Asthma , reflux (
Heartburn ) or
Post-nasal Drip . Other causes of chronic cough include chronic
Bronchitis and medications such as ACE inhibitors. Coughing can happen voluntarily as well as involuntarily.
The physiological action of coughing is responsible in part to the
Vagus Nerve , which runs through the
Lungs to the
Brain . The vagus
Nerve is activated when
Capsaicin is released, which stimulates the
Sensory Nerve endings. Centrally acting cough suppressants, such as
Codeine and
Dextromethorphan , reduce the urge to cough by inhibiting the capsaicin-induced sensory nerve by
Depolarization of the vagus nerve.
In severe cases, prolonged coughing can cause fatigue fractures of lower ribs and
Costochondritis , an
Inflammation of the connective tissue between the breastbone and the ribs. It can also lead to fainting spells when coughs are prolonged and forceful. In certain cases, it can even lead to abdominal or pelvic
Hernias .
Coughs can be treated with
Cough Medicine s. Dry coughs are treated with cough suppressants (antitussives) that suppress the body's urge to cough, while productive coughs (coughs that produce
Phlegm ) are treated with expectorants that loosen
Mucus from the
Respiratory Tract .
