Act that moves food from the mouth to the stomach. The tongue pushes liquid or chewed food mixed with saliva into the pharynx. Reflex takes over as the soft palate rises to close off the nasal cavity; the larynx rises and the epiglottis covers the trachea, interrupting breathing. Pressure in the mouth and pharynx pushes food toward the esophagus, whose upper sphincter opens to let food in and closes to prevent backflow. Breathing resumes as the larynx lowers. As peristalsis pushes food to the stomach, the lower esophageal sphincter opens and then closes to prevent reflux. Painful swallowing is usually caused by inflammation; other problems are caused by blockage or disorders affecting the motions of swallowing.
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