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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