What is the swallowing reflex?The swallowing reflex is a foreign reflex of the human body, which makes it possible to absorb food and fluid.
The swallowing reflex is innate and reflexive, ie reflex-like, controlled. To absorb and transport food, this reflex is essential. Man swallows between 1000 and 3000 times a day. By absorbing the food through the oral cavity, it then enters the esophagus.
Swallowing is triggered by the touch of the palatal arches, the tongue and the posterior pharyngeal wall. While the person is swallowing, breathing stops. This act is regulated by the swallowing center located in the brain stem. The act of swallowing may also be impaired and is referred to as a swallowing disorder.
Depending on the type of food that the person consumes, the size and duration of swallowing varies. The duration depends on how well the food was chewed and mixed with saliva. On average, the duration of swallowing is between 8 and 20 seconds.
Function & Task
The swallowing process is divided into individual phases. Each of these phases has its own task to fulfill.
The preparatory phase is the process that makes the actual swallowing process possible. The food must first be sufficiently chewed and mixed with saliva so that the spine can slide through the esophagus.
The transport phase is the second step of the reflex. With the mouth closed to prevent saliva loss and avoid swallowing extra air, the tongue pushes against the palate and the swallowing process is triggered. About the Rachenenge the food bolus is transported into the throat. The muscles of the tongue provide wavy applications for the triggering. Swallowing is triggered when the tongue base or the back of the pharynx is touched by the bolus.
In the pharyngeal transport phase, the upper and lower airways are sealed. This prevents the passage of food into the nose and possible ingestion. When swallowing, there is pressure equalization in the middle ear and an external pressure. This happens when the soft palate is tense and thereby additionally the ear trumpet widens.
If the nasopharynx is not closed during swallowing, chyme can enter the airways. Also, the larynx must be closed by the epiglottis. The upper pharyngeal cords (constrictor pharyngis superior muscle) contract and thus the occlusion of the airways is complete. The vocal folds are closed, the epiglottis sinks and the musculature of the floor of the mouth contracts. As the larynx gets higher, the epiglottis and laryngeal inlet become closer so that the lower airways are threefold protected. The upper sphincter of the esophagus opens and the food can be transported.
In the last phase, the esophageal transport phase, the muscle closes again. The food bolus has landed in the esophagus. The airways are reopened. The bolus takes its usual course. The stomach opens, and after the bolus is found in the stomach, it closes again. The swallowing act is over.
Diseases & complaints
During pregnancy the swallowing act of the child is formed. But if it comes to malformations in the central nervous system or in the digestive tract, the swallowing reflex is disturbed. Even in older people swallowing may occur.
The symptoms associated with a dysphagia are often a lumpy sensation in the throat, choking reflex when swallowing or coughing during ingestion.
The causes of a given swallowing disorder may be a psychological cause, but also a concomitant of a neurological or chronic disease. Especially in patients with multiple sclerosis or ALS, a review is required. Other physical causes that affect the swallowing reflex are sometimes injuries and tumors.
Often, dysphagia are side effects of a severe cold or tonsillitis. The swelling of the mucous membranes makes swallowing more difficult.
A neurogenic disorder is the most common cause of impaired swallowing reflex. After a stroke, a meningitis or a disease such as Parkinson's. Even with muscle wasting, a disease of the muscles, difficulty swallowing occurs.
With tumors or after operations in the neck, mouth and head area swallowing complaints are very frequent. If the cervical and oesophageal area is in contact with a foreign body over an extended period of time, dysphagia sets in. The same can be caused by poisoning or chemotherapy.
In younger patients, the problems are in the psychological area. The sufferers have the feeling of constantly having a lump in their throats. Children often suffer from congenital malformations.
In the elderly, it decreases efficiently when swallowing. In presbyphagia, the reaction time of the muscles is slowed down. Tooth loss and dried out mucous membranes make swallowing difficult. Also, a dysphagia may occur as a concomitant dementia.