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Amanda Dermer
Keane Archibald
Dayana Jimenez
Courtney Blazer
 Chapter
18: Lesson 1
 Eighth
Graders
 Age: 13-14
 Digestion
 Absorption
 Elimination
Digestive System
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The purpose
define the function of
each organ
 the pathway food
takes through the
digestive tract
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Work Sheet Fill
in the Blank
Digestive System
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The organs and parts of
the digestive pathway:
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Oral cavity
Pharynx
Esophagus
Stomach
Small Intestine
Large Intestine
Digestive System
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Teeth
Tongue
Liver
Pancreas
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The process that breaks down food into
substances that can be absorbed by the body for
energy, growth, and repair.
Ingestion:
Mouth, Teeth & Tongue
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The function of the mouth is to
ingest food sources
The teeth are used for
mastication
 breaking food down into
smaller pieces
The tongue forms food into a
ball to prepare for swallowing
Ingestion:
Mouth, Teeth & Tongue
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The mouth, teeth, and tongue play a role in
mechanical digestion.
Mechanical digestion physically prepares food
for chemical digestion by enzymes.
Salivary Glands
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Secretes saliva
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a watery solution
containing an enzyme that
starts the digestion
Cleanses the mouth
Dissolves food chemicals
Moisten food
Salivary Glands
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The salivary glands begin the process of
chemical digestion.
Pharynx
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After leaving the mouth, food is
passed on to the pharynx.
As you swallow:
 Uvula: prevents food from
passing into the nasal cavity.
 Epiglottis: prevent food
from entering the respiratory
tract.
Esophagus
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Food passes through the
pharynx into the
esophagus
 Extends from the
pharynx to the
stomach
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Primary Function;
 Carry foods and
liquids to stomach
 Peristalsis moves food
though the digestive
tract
Stomach
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Located below the
esophagus
A hollow, saclike organ
 Consists of three layers
of muscles
 Flexible, allowing it to
expand when you eat.
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Stomach
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A temporary “storage tank” where the chemical
breakdown of proteins begin.
The food is mixed together with gastric juices,
secretions from the stomach’s lining
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containing pepsin and hydrochloric acid.
Stomach
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As the stomach fills:
stomach contract
 churn the food and
gastric juices together
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This produces chyme
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a creamy, fluid mixture of
food and gastric juices .
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The passage of digested food from the digestive
tract into the circulatory system.
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The small intestine is the major absorption site.
Small Intestine
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The major part of digestion and
absorption
20 to 23 feet in length
Secretions from the pancreas,
liver, and intestinal juices
complete the chemical
breakdown of all food.
Small Intestine
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Millions of fingerlike
projections called villi
Each villus contains a
network of capillaries
which absorb digested
food particles from the
small intestine.
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Once food particles
enter the capillaries in
the villi, they are carried
throughout the body by
the blood.
Small Intestine
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Three parts to the small
intestine
 Duodenum
 Food enters here
from the stomach
 Jejunum
 The middle section
of the SI
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Ileum
 Allow one way
flow into the large
intestine.
The Liver & Pancreas
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Liver: 2nd largest organ in the
body.
 Acts to clear the blood of
toxins then excreting them
in the bile.
 Bile is a yellowish-green,
bitter fluid important in
the breakdown of fats.
Liver & Pancreas
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The pancreas produces 3 enzymes:
Trypsin, which digests proteins
 Amylase, which digests carbohydrates
 Lipase, which digests fats
 Located in the C of the SI’s duodenum.
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Gallbladder
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Storage organ for bile
produced from liver
Located below the liver
The small intestine
stimulates the release of
bile into the duodenum.
Not required for
digestion
Large Intestine
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Starts Ascending colon
Ends at the anus.
 A.K.A. the colon
 5 to 6 feet long
Large Intestine
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Unabsorbed materials:
 leave the small intestine in the form of liquid and
fiber
 enter the large intestine
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Absorbs most remaining
 Water
 Vitamins
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The expulsion of undigested food or body
wastes.
Elimination
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Harmless bacteria in the
large intestine change the
consistency of the
undigested food into a
semisolid waste, called feces
Feces passes from the body
through the anus
Termed “bowel movement”
Activity: Place that Organ
Lifestyle & Dietary Factors
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Eat at least 3 servings from a variety of fruits
and vegetables to avoid constipation
Practice good hand washing hygiene
Throw food away after it falls on the floor
Wash all foods before eating
Decrease caffeine consumption
 See
Fact Sheet for More Dietary Info
Dietary Activity
Unhealthy Diet
Scenario
Medications
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Some over the counter drugs that will help aid in
the relief of constipation and diarrhea.
Diarrhea
a. Imodium AD
b. Pepto-Bismol
 Constipation
a. Citrucel
b. Ex-Lax
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Stats of Constipation & Diarrhea
Deaths due to Constipation & Diarrhea
Constipation
17%
Infectious Diarrhea
Constipation
Infectious
Diarrhea
83%
Create your own digestive tract
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Each group will be representing a different
part the digestive tract
A member from each group will stand in
front of the class and explain their organs
function during the process of digestion
 Be creative and have fun with the activity