The contraction of the genioglossus and styloglossus (both XII) also contributes to the formation of the central trough.Īt the end of the oral preparatory phase, the food bolus has been formed and is ready to be propelled posteriorly into the pharynx. The tongue is then elevated to the roof of the mouth (by the mylohyoid (mylohyoid nerve-V 3), genioglossus, styloglossus and hyoglossus (the rest XII)) such that the tongue slopes downwards posteriorly. The intrinsic muscles of the tongue (XII) contract to make a trough (a longitudinal concave fold) at the back of the tongue. The trough obliterates against the hard palate from front to back, forcing the bolus to the back of the tongue. Any food that is too dry to form a bolus will not be swallowed.Ī trough is then formed at the back of the tongue by the intrinsic muscles (XII). The bolus is ready for swallowing when it is held together by saliva (largely mucus), sensed by the lingual nerve of the tongue (VII-chorda tympani and IX-lesser petrosal) (V 3). ![]() Buccinator (VII) helps to contain the food against the occlusal surfaces of the teeth. This results in a bolus which is moved from one side of the oral cavity to the other by the tongue. The following stages describe the normal and necessary actions to form the bolus, which is defined as the state of the food in which it is ready to be swallowed.įood is moistened by saliva from the salivary glands ( parasympathetic).įood is mechanically broken down by the action of the teeth controlled by the muscles of mastication (V 3) acting on the temporomandibular joint. Upon entering the oral cavity, the mandible elevates and the lips adduct to assist in oral containment of the food and liquid. Prior to the following stages of the oral phase, the mandible depresses and the lips abduct to allow food or liquid to enter the oral cavity. Sagittal view of mouth and pharynx Phases Oral phase The autonomic nervous system (ANS) coordinates this process in the pharyngeal and esophageal phases. Swallowing is a complex mechanism using both skeletal muscle ( tongue) and smooth muscles of the pharynx and esophagus. The reflex is initiated by touch receptors in the pharynx as a bolus of food is pushed to the back of the mouth by the tongue, or by stimulation of the palate (palatal reflex). The pharyngeal swallow is started by the oral phase and subsequently is coordinated by the swallowing center on the medulla oblongata and pons. The oral phase, which is entirely voluntary, is mainly controlled by the medial temporal lobes and limbic system of the cerebral cortex with contributions from the motor cortex and other cortical areas. Each phase is controlled by a different neurological mechanism. However, from the viewpoints of physiology, of speech–language pathology, and of health care for people with difficulty in swallowing (dysphagia), it is an interesting topic with extensive scientific literature.Įating and swallowing are complex neuromuscular activities consisting essentially of three phases, an ' oral, pharyngeal and esophageal phase. Swallowing comes so easily to most people that the process rarely prompts much thought. In colloquial English, the term "swallowing" is also used to describe the action of taking in a large mouthful of food without any biting, where the word gulping is more adequate. The portion of food, drink, or other material that will move through the neck in one swallow is called a bolus. In the human body the automatic temporary closing of the epiglottis is controlled by the swallowing reflex. If the process fails and the material (such as food, drink, or medicine) goes through the trachea, then choking or pulmonary aspiration can occur. Swallowing is an important part of eating and drinking. Swallowing, sometimes called deglutition in scientific contexts, is the process in the human or animal body that allows for a substance to pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis. ![]() JSTOR ( May 2009) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. ![]() This article needs additional citations for verification.
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