1. JH-KEADLE
Digestive System

2. Nutrients
Substances in food that provide raw materials and energy the body needs to live
Our digestive system turns the chemical energy in these nutrients into energy we can use

3. Functions of the Digestive System
Digests food into molecules the body can use (physical or chemical change)
Absorbs nutrient molecules and carries them around the body (physical change)
Eliminates waste material from unused nutrients

4. Digestion body breaks down food into small nutrient molecules
mechanical
chemical

5. Mechanical Digestion
Food is physically broken down into smaller pieces
Begins in the mouth
Teeth chewing/tearing
Movement of
smooth muscles

6. Chemical Digestion
Chemicals produced by the body break foods into their smaller nutrients
mouth
stomach

7. Absorption
Process by which nutrient molecules pass through the wall of your digestive system into your blood
The lining of the small intestine is covered in villi that aid in absorption

8. Elimination Materials that are not absorbed leave the body as waste
The waste material left over after food is digested must leave the body to prevent illness

9. Which is not a function of the digestive system?
Breaking down food into molecules the body can use
Absorbing food molecules into the blood to deliver to the body
Changing waste into molecules the body can use
Eliminating undigested waste from the body

10. Organs of the Digestive System
Mouth Rectum
Esophagus Anus
Stomach Pancreas
Small intestine Gall Bladder
Large intestine Liver

11. Mouth Digestion begins in the mouth Mechanical – teeth
Chemical - saliva

12. Esophagus Muscular tube that connects your mouth to your stomach
moves food down into your stomach
using involuntary muscle
contractions (peristalsis)
Lined with mucus that
allows food to slide down

13. The Stomach J-shaped muscular pouch
Most mechanical digestion takes place in the stomach
Chemical digestions also takes place
Stomach secretes digestive juice (enzymes) that break down food
Average adult stomach holds 2 liters
Mucus keeps the acids from burning a hole in your stomach

14. Stomach

15. Modeling
Place the marble in the end of the tube and squeeze it down into the balloon.

16. Modeling What do you think this could be a model of? What is the tube?
What is the balloon?
What is the marble?
What is the soap?
esophagus
stomach
food
saliva and mucus

17. Which is not an example of mechanical digestion?
Teeth chewing food
Tongue breaking up food
Smooth muscles in stomach churning food
Hydrochloric acid breaking down proteins

18. Small Intestine Where most of the chemical digestion takes place
Where most of the absorption takes place
Covered in villi which
enlarge the surface area

19. Small Intestine Most digestion happens here.
Intestinal juice (full of enzymes)
breaks down food.
Digestive Helpers
Liver, Gall bladder, Pancreas
Digested food is absorbed
through the villi into a network of
blood vessels that carry the
nutrients to all parts of the body.
e) By the time food leaves the small intestine, it is empty of all nutrients except water.

20. Small Intestine
The villi increase the surface area that can absorb nutrients

21. Where does most digestion take place?
Mouth
Stomach
Small intestine
Liver

22. Liver Breaks down medicines and other chemicals
Produces bile that breaks up fat particles
The gall bladder
stores bile

23. Pancreas Produces enzymes that flow into the small intestine
Secretes insulin
Causes diabetes when it does not make insulin

24. Large Intestine Last section of the digestive tract
Food spends hours here
Where water is absorbed
Vitamins B & K are made by bacteria in the large intestine

25. Rectum and Anus
Rectum – end of the large intestine, forms the solid waste
elimination
Anus – muscular opening at the end of the rectum

26. Which cell parts are like the digestive system?
Which one makes energy?
mitochondria
Which one allows materials to pass in and out?
cell membrane
Which one helps get rid of waste?
lysosomes

28. The Digestive System Interacts with:
muscular system (smooth
muscle) to move and digest food
respiratory system to provide
oxygen
circulatory system to move
nutrients