Drinking a glass of water, eating a candy bar or sitting down to a good meal are very pleasurable activities. They are so automatic we take them for granted. We also take for granted the pleasure we get form the tastes and textures of the foods we eat.
Normal swallowing is fast and well coordinated: Normal swallowing of food and liquid requires coordination of a large number of muscles in the mouth, throat (pharynx) and esophagus (a tube that leads from the pharynx to the stomach). As food is placed in the mouth, we close our lips to prevent drooling. Muscles of the tongue and jaw move food around in the mouth for chewing. When chewing is finished, the food is collected into a ball by movements of the tongue.
The swallow begins as the tongue pushes the food upward and backward toward the back of the mouth and the throat (pharynx). As the tongue pushes the food or liquid toward the back of the mouth, the muscles in the pharynx begin to move to receive the food. The top of the windpipe (larynx) begins to lift, move forward, adn close to keep food from going into the lungs. The soft part of the roof of the mouth (the soft palate) lifts to close off the entrance to the nose.
As food passes over the back of the tongue and enters the pharynx, muscles in the pharynx contract to squeeze the food through the pharynx and into the esophagus. Ass the food approaches the entrance to the esophagus, the valve at the top of the esophagus opens to allow the food to pass. Muscles in the esophagus then contract to push the food from the top of the esophagus through the valve at the bottom of the esophagus and into the stomach.
Normal swallowing is safe and efficient: Normal swallowing is a very fast process, taking less than 2 seconds to move the food from the mouth, through the pharynx, and into the esophagus. Normal swallowing is safe because the larynx (the entrance to the windpipe) is closed as the food passes. The food is normally moved efficiently through the mouth and pharynx, with very little trace of food or liquid left behind.
If larger amounts of food are swallowed at one time, the swallow takes slightly longer and the muscles of the mouth and pharynx work simultaneously, rather than in a sequence. At times, we hold our breath to protect the windpipe in anticipation of a very large swallow. Though normal swallowing changes at times with the types of food swallowed, the safety and efficiency of the swallow do not change.