1. Chapter 3
“Food and Digestion”

2. Section 2.1 Food and Energy

3. Section 2.1 Food and Energy

4. Section 2.1 Food and Energy

5. Section 2.1 Food and Energy

6. Section 2.1 Food and Energy

7. Section 2.1 Food and Energy
Homework: READ pp

8. Section 2.2 Healthy Eating

9. Section 2.3 The Digestive Process Begins
Functions of the Digestive System
1.) It breaks down food into molecules the body can use
2.) The molecules are absorbed into the blood and carried throughout the body.
3.) Wastes are eliminated from the body
Digestion is the process which your body breaks down food into small nutrient molecules.
Absorption is the process by which nutrient molecules pass through the wall of your digestive system into your blood. Materials that are not absorbed, such as fiber, are eliminated from the body as wastes.
Enzymes are proteins that speed up chemical reactions in the body.

10. Section 2.3 The Digestive Process Begins
Mouth: both mechanical and chemical digestion begin in the mouth. Tongue, teeth, & saliva from the salivary glands change food into soft mass called bolus.
Esophagus: muscular tube moves food to stomach using peristalsis (muscle contractions) – mechanical digestion. The esophagus is sealed off by a flap of tissue called the epiglottis as you swallow to prevent food from entering the windpipe.
Stomach: a muscular sac that turn food into a thin, watery liquid called chyme. Mechanical digestion by peristalsis/Chemical digestion by digestive juices/enzymes.

11. 2.3 The Digestive Process Begins
Homework: READ pp

12. Bill Nye - Digestion
23 Minutes

13. Section 2.4 Final Digestion and Absorption
Small Intestine: long tube (small diameter) that functions in chemical digestion and nutrient absorption. Lined with villi: finger-like projections. Each villus is composed of cells that have microvilli. Cells transport nutrients to the bloodstream through capillary beds to be distributed to the body cell. Pancreas, liver, and Gallbladder all help the small intestine with chemical digestion.
Large Intestine: absorbs water from undigested chyme. Chyme can be in L.I. as long as three days.
Rectum & Anus: rectum stores solid waste (feces) until it is released from the body through the anus.

14. Section 2.4 Final Digestion and Absorption
Brainpop

15. Section 2.4 Final Digestion and Absorption

16. Section 2.4 Final Digestion and Absorption
Human GI Tract

17. Section 2.4 Final Digestion and Absorption
“As the Stomach Churns” LAB (2 Days)

18. Chapter 2 – Study Guide/Review Answers
1.) C 2.) D 3.) D 4.) C 5.) A
6.) complete 7.) Minerals 8.) true
9.) Peristalsis 10.) small
12.) Fiber helps keep the digestive system functioning properly.
14.) The epiglottis is located in the back of your mouth and seals off your windpipe
When you swallow to prevent food from entering.
15.) It pushes food and undigested material through the
Digestive system.
16.) The pancreas produces enzyes that flow into the small
Intestine and help break down starches, proteins, and fats.

19. Chapter 2 – Study Guide/Review Answers
17.) Villi absorb nutrient molecules. They cover the surface of the small intestine.
24.) Milk, yogurt, and cheese group; 2 to 3 servings
Standardized Test Prep
1.) D 2.) G 3.) B 4.) F 5.) B
6.) mechanical digestion causes a physical change as the pieces
Of food are broken down into smaller blocks with the help of
Enzymes. The processes are similar in that they break down food
into smaller pieces or components. The processes are
different in that mechanical digestions does not involve
chemical reactions that use enzymes. Mechanical digestion
occurs in the mouth and stomach. Chemical digestion occurs
in the mouth, stomach, and small intestine.