2. Esophagus and Stomach
Rosemary and Sasha
Background info
● Esophagus: muscular tube
connecting the throat
(pharynx) to the stomach
● Stomach: muscular organ
located on the left side of
the upper abdomen, involves
the 2nd stage of digestion
What is peristaltic movement and how does it
function in the esophagus?
● The muscles contract in a wave-like motion to move food
through the esophagus called Peristalsis
● Food then propels a ball of food (bolus) along through
the upper gastrointestinal tract & chyme in the stomach
Does any digestion of food occur in the esophagus?
● No; the esophagus is the organ that pushes swallowed
food to the stomach
What are the primary functions of the stomach?
● To breakdown and digest food in order to extract
necessary nutrients from what you have eaten
What role does the stomach play in
decontaminating the incoming food matter?
● The stomach contains many acids which help break down
food matter & kill bacteria
What is chyme and how does the stomach mix this
material?
● The chyme is a “pulpy” acidic fluid that passes from the
stomach to the small intestine
● The stomach then mixes this material by combining food,
enzymes and gastric juices
What cells in the stomach function to form enzymes
and acids?
● Parietal cells in the stomach function to form enzymes
and acids
● The digestive glands & intestines must produce various
enzymes (pepsin and acid) to break down the food
Why doesn’t gastric juice digest the inside of the stomach?
● The stomach has a membrane on the inside called
mucus.
● It forms a layer between the deadly gastric juices and the
lining of the stomach walls.
● The mucus lining prevents the acids present in the gastric
juices from damaging the stomach.(it is strong enough to
withstand the gastric acids).
What are sphincters and how are they related to the stomach?
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Circumferential muscles that can relax or constrict to
regulate the passage of material through a particular
area.
The stomach is bound by two sphincters in humans:
(the lower esophageal sphincter that keep stomach
acid in the stomach and the pyloric sphincter that
regulates the flow of food in the stomach into the
duodenum).
Open and close when needed to either allow food
into the stomach or to allow digested food out of the
stomach.
What mechanical and chemical digestion occurs in the stomach?
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Mechanical digestion: involves physical breakdown of food.
begins in the mouth-teeth,tongue and palates.
esophagus-peristalsis.
stomach
Chemical digestion: involves the chemical breakdown of food.
Begins in the stomach(small intestines).
Occurs as the churning food makes contact with the digestive juice (a juice
produced by the cells in the lining of the stomach).
References
Barron, J. (2007, March 12). Stomach Acid & Digestion. Retrieved December 7, 2015, from Baseline of Health
Foundation website: http://jonbarron.org/article/stomach-acid#.VmWxKigViko
Digestive Disorders Health Center. (n.d.). Retrieved December 7, 2015, from Web MD website: http://www.webmd.
com/digestive-disorders/picture-of-the-stomach
Esophagus Conditions. (n.d.). Retrieved December 7, 2015, from Web MD website: http://www.webmd.
com/digestive-disorders/picture-of-the-esophagus
Picture of the Stomach [Image]. (n.d.). Retrieved from http://www.webmd.com/digestive-disorders/picture-of-thestomach
The stomach and its role in digestion. (n.d.). Retrieved December 7, 2015, from Laparoscopic.md website: http:
//www.laparoscopic.md/digestion/stomach