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CH 18: Nutrients & Digestion
What you should read! Chapter 18
pages 523 - 529
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Digestive System
The process of breakingdown food so it can beabsorbed and moved byblood system
2 forms of digestion
1. Chemical Digestion chemicalaction of breaking down food by
enzymes or acids
2. Mechanical Digestion - thephysical action of breaking down food
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DS Pathway
The minute you take a bite of aTwinkie your digestive systemstarts to work!!
Ingestion/ Digestion
1. The MouthMechanical Digestion
Teeth grind & tear food tosmaller pieces. Tonguehelps to mix it.
Chemical Digestion
Salivary Glands producesaliva that contains anenzyme to start breakingdown food.
Go
tofigure 11,
page 523
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Now the food is somewhat broken down and
your mouth has made it mushy with
chemicals. Where does it go?
2. The Throat
Epiglottis Small flap that
closes over windpipe smooth muscle
Esophagus Pipe that
transports food to the
stomach
NO digestion occurs
Peristalsis - smooth
muscle contractions that
move food down through
the pipe
Go
to
figure 13,page 525
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Now that Twinkie is really mushy and the
peristalsis muscles have pushed it down
into your stomach. What happens?
Digestion
3. The Stomach
J-Shaped organ lined with muscle
Mechanical Digestion
smooth muscle mixes and
breaks down food
Chemical Digestion
Gastric Juices/acids
hydrochloric acid insidestomach
-Food is now a thin watery liquid
called Chyme
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Twinkie is just plain mushy mixed with acid, & mucus;its like really runny oatmeal. Where does it go?
Digestion
4. The Small Intestine~6 meters of coiled tubes wrapped in smooth
muscle
Most of the digestion occurs here
Chemical Digestion
acids break down food even more
Mechanical Digestion
Smooth muscle push food throughintestines
AbsorptionVilli Small fingerlike projections that line the
inside walls
Digested food is absorbed into blood vessels
Go
to
figure 13,page 525
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Does any other organ help in digestion?
Accessory Organs
The Liver Produces bile (breaks up fat)
Aids drug detoxification
The Gall Bladder Stores bile
Releases some bile intoduodenum to help in digestion
The Pancreas Produces pancreatic juices
which help in digestion
Produce insulin which controlsblood sugar levels
Food does not pass through these organs!
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So where does the food that doesntget absorbed go?
Absorption
Large Intestine Horseshoe shaped around the
small intestine
Contains all the undigestedfood, water, etc
Absorbs water-maintainhomeostasis
Mix stuff into solid mixture
Elimination
Rectum Very end of the large intestines
Stores solid waste, before itleaves body through anus
Muscles control the release
Go to
figure 4,page 488
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1. Whatare the structures inside thesmall intestine called thatabsorbthe nutrients?
2. What is the flap of muscle that
covers your windpipe?3. What is the role of the gallbladder?
4. Name the muscle Contractions thathelppush food through the D.S.
5. Where does most of the digestiontake place (be specific)?
6. Explain the role (s) of the largeintestine be sure to include the stageor stages?
I know these
answers!! Im so
smart Im floating
with knowledge
Quick Quiz
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Identify The Parts
1 2
3
4
5
6
8
7
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Quick Quiz
1. Whatare the structures inside thesmall intestine called thatabsorb thenutrients?
2. What is the flap of muscle that coversyour windpipe?
3. What is that pipe that transports foodto the stomachcalled?
4. Name the muscle Contractions thathelppush food through the D.S.
5. Where does most of the digestion takeplace?
6. What organabsorbs the water?
I know these
answers!! Im so
smart Im floating
with knowledge
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Answers
1. Villi
2. Epiglottis
3. Esophagus
4. Peristalsis
5. Duodenum (small intestine)
6. Large intestines
Yummy, yummy
in my tummy,
Ms. Von is so
funny!
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Answers
1. Mouth/Salivary
glands
5. Small intestines
4. Large intestines
3. Stomach
6. Rectum
7. Pancreas
8. Liver
2. Esophagus
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