The Digestive System
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The duodenum produces large amounts of mucus to protect the intestinal lining from acid in the
chyme.
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The esophagus empties into the stomach, which mixes food with digestive juices such as the
enzymes pepsin, and lipase.
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Other organs that play a role in digestion include the liver, gallbladder, and pancreas.
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The liverprocesses nutrients absorbed in the blood by the small intestine, creating glycogen
from carbohydrates.
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What's left in the digestive tract passes into the large intestine.
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Mechanical digestion is what begins in the mouth.
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The digestive tract has four layers.
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The digestive system is also called the gastrointestinal tract and the alimentary canal.
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The digestive tract is approximately 30 feet long through the middle of the body.
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A person has more than 400 species of bacteria in the colon.
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The esophagus does not take part in digestion.
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Amylase is a digestive enzyme that breaks down carbohydrates.
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Chyme is a thick liquid of partially digested food that is passed from the stomach to the small
intestine.
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The bolus is a battered, moistened, and partially digested ball of food that passes from the
mouth to the stomach.
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Villi: Fingerlike projections in the small intestine that increase the absorption area of the
intestine.
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Chemical digestion begins in the stomach.
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Food in the stomach is broken down by gastric juice, which contains hydrochloric acid and
pepsin.
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The large intestine is wider and heavier than the small intestine.
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The large intestine removes water from the waste products of digestion and returns some of it
to the bloodstream.
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The esophagus is approximately 25cm long.
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Muscles contract in waves to move the food down the esophagus.
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Food stays in your stomach for 2 to 3 hours.
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The pharynx is the portion of the digestive tract that receives the food from your mouth.
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The stomach is a sac-like organ with strong muscular walls.
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The duodenum is responsible for the continuing breakdown process.
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It normally takes about 36 hours for stool to get through the colon.
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The gallbladder is a storage sac for excess bile.
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Cells in the lining of the stomach secrete a strong acid and enzymes that are responsible for the
breakdown process.
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Contents of the small intestine start out semi-solid, and end in a liquid form after passing
through the organ.
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The pancreas secretes digestive enzymes into the duodenum, the first segment of the small
intestine.
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The pancreas makes insulin, secreting it directly into the bloodstream.
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The colon is a 6-foot long muscular tube that connects the small intestine to the rectum.
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Bile from the liver secreted into the small intestine also plays a role in digesting fat.
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The outside of the tongue contains a rough surface for gripping food as it is moved by the
tongue’s muscles.
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The mouth has 3 sets of salivary glands.
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By the time food leaves the small intestine, around 90% of all nutrients have been taken from
the food that entered it.
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The first function of the digestive system is ingestion, or the intake of food.
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The digestive system secretes around 7 liters of fluids.
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The muscular layer of the digestive tract contracts and relaxes to force the food through the
system to organs that need it.
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The body cannot use protein or carbohydrates in their whole forms.
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Peristalsis is the involuntary movement of material through the digestive system.
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The walls of the digestive tract have four layers.