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Unit 19: Biology Part 2 Page 42 of 137

1. Digestion. Digestion things (starches) into smaller
involves the breakdown of sugar molecules.
what we consume into  Pepsin helps us digest
nutrients. The first step is protein in our stomachs.
mechanical digestion—  Pancreatic lipase breaks
chewing. After we down fats. It is secreted by
mechanically break down the the pancreas.
food with our teeth, we begin
chemical digestion. Hormones
Chemical digestion breaks

down what we eat and drink What is happening when we feel
chemically. Chemical hungry? Or when we feel thirsty?
digestion is mostly What we are feeling is hormones
accomplished by proteins signaling our brains that we need
called enzymes. food or we need water.
2. Absorption. After we’ve Hormones—made by the endocrine
broken down the nutrients system—play a large role in our
we need, we absorb them digestion process. They help
into our body. This step is maintain homeostasis by

called absorption. stimulating appetite, thirst, as well
3. Elimination. Lastly, we as many, many other bodily
excrete solid and liquid functions.
waste.
Digestive Organs

Enzymes
The digestive system is essentially

Enzymes make reactions go one long tube. It begins with the
faster—they are catalysts. They mouth and ends with the anus. On
are found at every important step average, it is thirty feet long! In
of digestion. between the mouth and anus are
many organs which play various
Here are some of the key roles; esophagus, stomach, small
enzymes: intestine, large intestine, and anus,
to name a few.
 Amylase is found in our
saliva (in our mouths). It Food is moved through the tube via
helps breaks down bread-like muscle contractions. The muscle
contractions start in the esophagus

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