Question

the digestive system - the esophagus and stomach
the esophagus is a muscular tube about ten inches long that conveys food from the throat or pharynx to the stomach. it lies behind the trachea or windpipe and the heart. as you swallow, two sets of muscles act together to force the food and water through the esophagus and into the stomach. one set is circular and presses inward. the other set runs up and down and also contracts inward forcing the food downward. this wave - like motion is called peristalsis. since the ring of muscle contracts behind the food, you can swallow upside down. in the esopha - gus there is no chemical digestion since the esophagus does not produce any enzymes. it does secrete mucus, however. this mucus acts as a lubricant permitting the food to slide through the esophagus more easily.
the stomach is a j - shaped sac lying in the abdomen just under the diaphragm. the diaphragm is a muscle that forms the floor of the chest cavity. the stomach is made of three layers of smooth muscle tissue, each running in a different direction. the stomach is mainly a store - house for food. it can hold as much as two quarts of food. peristal - tic waves, moving across the stomach, break the food up into small pieces. it may continue to churn the food for up to five hours before passing it on to the small intestine.
the stomach aids the process of chemical digestion by mixing the food with gastric juices produced by the lining of its walls. gastric juices are made up of water, mucus, hydrochloric acid, and the enzyme, pepsin. the water softens the food. the mucus protects the stomach from digesting itself. the hydrochloric acid creates a favorable envi - ronment for the enzyme pepsin to work. pepsin begins the digestion of proteins. by the time the food leaves the stomach to enter the small intestine, it is a semi - liquid called chyme.
questions

1. what is the name of the wave - like process that moves food down the esophagus?
2. does any chemical digestion occur in the esophagus?
3. what acid is present in the stomach? acid
4. what enzyme do gastric juices contain? a)

what food type does it work on? b)

1. what is the semi - liquid food that leaves the stomach?
2. what word best describes the function of the stomach?

activities
locate diagram 6 on activity sheet 4 and diagram 3 on activity sheet 3. color the esophagus orange and the stomach purple. next, cut out diagram 6 and diagram 3 and glue them to your display sheet. then, label the esophagus and stomach.
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Explanation:

1. The text mentions "the wave - like motion is called peristalsis".
2. The text states "In the esophagus there is no chemical digestion since the esophagus does not produce any enzymes".
3. The text says "Gastric juices are made up of water, mucus, hydrochloric acid...".
4. The text mentions "the enzyme, pepsin" and "Pepsin begins the digestion of proteins".
5. The text says "By the time the food leaves the stomach to enter the small intestine, it is a semi - liquid called chyme".
6. The text states "The stomach is mainly a store - house for food".

Answer:

1. Peristalsis
2. No
3. Hydrochloric
4. a) Pepsin; b) Proteins
5. Chyme
6. Store - house