Cough reflex

Cough is a reflection of the human body's protective respiratory tract. When the respiratory tract (oral, throat, trachea, bronchus) is stimulated (such as inflammation, foreign body), it is a kind of physiology caused by the impulses of nerve endings into the medulla cough center. Reflexes, through the action of coughing, expel airway secretions or foreign bodies (such as slimy sputum, bacteria, fibers) to keep the airway clean and unobstructed. Therefore, we can say that coughing is a beneficial action and is sometimes seen in healthy people. In general, for mild and infrequent cough, as long as the sputum or foreign body is discharged, it can be relieved naturally without the need to apply antitussives. However, for those dry cough without sputum or severe cough with sputum, it not only increases the patient's pain, affects rest and sleep, increases physical exertion, and even promotes the development of the disease, resulting in other complications. At this time, the disadvantages are greater than Profit. Antitussives should be applied appropriately to relieve cough. Coughing is a kind of action. It is essentially a strong and vigorous inhalation of the human body, then the glottis is closed, and the intercostal muscles and condyles are constricted successively, which can establish an intra-pulmonary pressure of about 40 kPa (kPa). Then the glottis suddenly opened, and the constriction quickly and forcefully contracted, causing the gas in the lungs to rush out of the respiratory tract at a high speed, ejecting the substances adhered to the respiratory mucosa, forming cough and sputum. Such a complex and coordinated action is composed of a series of reflections, called a cough reflex arc. The cough reflex arc includes four links: (1) Receptors of respiratory nerve endings, including mechanoreceptors, chemosensors, and lung stretch receptors. (2) The afferent nerve is the vagus nerve fiber. (3) The medulla cough center is located on the dorsal part of the medulla oblongata, adjacent to the respiratory center. (4) Efferent nerves, including vagal nerve efferent fibers, superior laryngeal nerve and cerebral nerve. They work together to complete the cough movement. There are many mechanoreceptors, chemoreceptors and lung distractors on the human respiratory tract mucosa. Therefore, mechanical stimulation of mucus, dust or foreign bodies, or chemical stimulation of smoke, poisonous gas, etc., and increased muscle tension caused by bronchospasm, all stimulated The nerve ending receptors excite the cough center of the medullary medulla through the afferent nerve, and then the impulse is emitted from the cough center. The efferent nerve acts on the intercostal muscles, the diaphragm, and the glottis to erupt cough. Any change or dysfunction in any of the above cough reflex arcs will cause cough movement disorders. The cough reflex can last for several days or even months. The cough associated with acute respiratory infections lasts for several days and can disappear after inflammation control. Cough caused by chronic bronchitis, asthma, smoking, etc., usually lasts for more than 3 weeks. Can be considered a chronic cough.