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Mouth, Esophagus and Stomach. In the Mouth. Soft and hard plates separate the nasal chamber from the mouth cavity. These two tubes join at the pharynx Soft palate forms into a piece of tissue that hangs down called the uvula. This lifts to close the nasal cavity during swallowing.
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In the Mouth • Soft and hard plates separate the nasal chamber from the mouth cavity. • These two tubes join at the pharynx • Soft palate forms into a piece of tissue that hangs down called the uvula. This lifts to close the nasal cavity during swallowing. • Below the pharynx the traches and esophagus begin.
Esophagus • Flexible Tube • About 25 cm long • Connects pharynx to stomach
Esophagus Wall • Several Layers • 1. Thick lining with a film of slippery mucus • 2. Glands, nerves and blood vessels • 3. 2 layers of muscle: • Circular, around the tube. • Longitudinal- length of the tube. • 4. Thin sheet of connective tissue to help anchor to surrounding tissues.
Peristalsis • Rhythmic contractions of circular and loingitudinal muscles. • Move bolus of food down the esophagus • http://www.westga.edu/~lkral/peristalsis/index.html
Stomach • Located beneath the diaphragm toward the left side of the abdomen. • Muscular bag that stretches as it fills with food. • 3 layers of muscle • Lengthwise, circular, diagonal • Contract rhythmically to mix food with gastric secretions (enzymes and HCL acid). • Lined with a mucus secretion called mucin to protect from gastric juices.
Sphincters • Cardiac sphincter. At junction of the esophagus and stomach. Ring of muscle, like a drawstring on a bag. Controls movement of food into stomach. • Pyloric sphincter. At the end of the stomach. Ring of muscle. Controls flow of chyme into the small intestine. Chymeis semi liquid, partly digested food in the stomach.
