The cough reflex is a protective reflex of the body, which means that when a person has pathological secretions (most often sputum) in the respiratory tract, or when a foreign body (especially in children) accidentally enters the respiratory tract (more often when a grain of rice falls into the trachea after a meal), it triggers the body’s reflex response and is expelled by coughing. The mechanism of coughing In fact, coughing may seem “simple”, just “coughing”, but it involves many parts and organs of the body. First of all, there is a special part of the human brain called the metencephalon, which is located below the cerebellum and is part of the brainstem. There is a group of nerve cells in the cerebellum that form a “cough center”, which means that this center is the “command” that controls coughing in the human body, and their task is to receive and “process and analyze Their task is to receive and “process and analyze” various stimuli that can cause coughing, and then send “signals” to the relevant nerves, which transmit the signals (or impulses) to the relevant muscles and organs (such as the vocal cords described below), which then respond in a coordinated manner to the cough. What are the nerves involved in coughing? They are mostly nerves related to the respiratory mucosa, such as the “vagus nerve”, the “glossopharyngeal nerve”, the “trigeminal nerve”, etc., as they are called by doctors, whose task is to transmit stimuli to the to the cough center. Other nerves involved in coughing are the “hypoglossal”, “phrenic” and “spinal” nerves, which are responsible for receiving “commands” from the respiratory center and transmitting impulses to the cough center. These nerves are responsible for receiving “commands” from the respiratory center and transmitting impulses to the parts or muscles that cause coughing, such as the pharyngeal muscles, the vocal cords, the diaphragm, and the respiratory muscles, and the coordinated action of these muscles or parts causes coughing to occur. This process is called the “cough reflex” by doctors. Specifically, the whole process of coughing is like this: a short inhalation, followed by the immediate closure of the vocal chambers, the simultaneous descent of the diaphragm, followed by a rapid contraction of the respiratory muscles and diaphragm, causing a rapid increase in intrapulmonary pressure, and then the sudden opening of the vocal chambers, with the high-pressure air ejected from the lungs and hitting the narrow vocal chambers, resulting in a special sound that is known as coughing. This is called coughing. Because of the high pressure air ejected during coughing, secretions or foreign bodies (such as inadvertently dropped rice grains) can be expelled from the respiratory tract. Cough reflex in disease states In pathological conditions, most coughs cannot be controlled at will. However, the human cerebral cortex can also influence the onset of coughing and can therefore control or produce it at will in some cases, most commonly in patients with chest or abdominal pain during coughing, who actively suppress it to avoid pain. In some diseases, the cough has a certain rhythm, for example, a “mono-cough” is more common in patients with laryngitis, bronchitis, early tuberculosis, and smokers, while others have a light cough from time to time even though they are not suffering from a disease. This is called a “habitual cough” and also falls under the category of “mono-cough”. Another type of cough that is quite disturbing is “spasmodic cough”, which is a paroxysmal, violent, and difficult to control cough, mostly seen in children with whooping cough, foreign body aspiration, bronchial asthma, endobronchial tuberculosis, and bronchial tumors. As for long-term chronic cough, it is more often caused by chronic respiratory diseases, such as the so-called “old chronic bronchitis” (chronic bronchitis in the elderly), bronchiectasis, chronic lung abscess, and cavitary tuberculosis.