Stage 3:Esophagus
At this point, the partially digested food enters the Esophagus, a narrow, muscular tube about 30 centimeters (12 inches) long, starts at the pharynx, passes through the larynx and diaphragm, and ends at the cardiac orifice of the stomach.
The wall of the Esophagus is made up of two layers of smooth muscles, which form a continuous layer from the Esophagus to the oten and contract slowly, over long periods of time. The inner layer of muscles is arranged circularly in a series of descending rings, while the outer layer is arranged longitudinally.
At the top of the Esophagus, is a flap of tissue called the epiglottis that closes during swallowing to prevent food from entering the trachea (windpipe). The chewed food is pushed down the Esophagus to the stomach through peristaltic contraction of these muscles. It takes only seconds for food to pass through the Esophagus, and little digestion actually takes place at this point!
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