1. Chapter 7
Section 1 The Digestive System
Objectives
Describe how the digestive system fuels body functions.
Compare mechanical digestion with chemical digestion.
Describe the parts and functions of the digestive system.

2. Digestive System at a Glance
Chapter 7
Section 1 The Digestive System
Digestive System at a Glance
Your digestive system is a group of organs that break down food so that it can be used by the body.
Food passes through the digestive tract. The digestive tract includes your mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.
The liver, gallbladder, pancreas, and salivary glands are also part of the digestive system.

3. Chapter 7
Section 1 The Digestive System

4. Chapter 7 Breaking Down Food
Section 1 The Digestive System
Breaking Down Food
The breaking, crushing, and mashing of food is called mechanical digestion.
In chemical digestion, large molecules are broken down into nutrients with the aid of enzymes.

5. Chapter 7
Section 1 The Digestive System

6. Digestion Begins in the Mouth
Chapter 7
Section 1 The Digestive System
Digestion Begins in the Mouth
Teeth With the help of strong jaw muscles, teeth break and grind food.

7. Digestion Begins in the Mouth, continued
Chapter 7
Section 1 The Digestive System
Digestion Begins in the Mouth, continued
Saliva contains an enzyme that begins the chemical digestion of carbohydrates.
Leaving the Mouth Once the food has been reduced to a soft mush, the tongue pushes it into the throat, which leads to a long, straight tube called the esophagus.

8. The Harsh Environment of the Stomach
Chapter 7
Section 1 The Digestive System
The Harsh Environment of the Stomach
The stomach is a muscular, saclike, digestive organ attached to the lower end of the esophagus.
Tiny glands in the stomach produce enzymes and acid to break food down into nutrients.
After a few hours of combined mechanical and chemical digestion, food leaves your stomach as a soupy mixture called chyme.

9. The Pancreas and Small Intestine
Chapter 7
Section 1 The Digestive System
The Pancreas and Small Intestine
The Pancreas is an organ located between the stomach and small intestine. Its makes fluids that protect the small intestine from the acid in chyme.
The Small Intestine is a muscular tube that is about 2.5 cm in diameter. In the small intestine, nutrients are absorbed into the bloodstream through fingerlike projections called villi.

10. Chapter 7
Section 1 The Digestive System

11. The Liver and Gallbladder
Chapter 7
Section 1 The Digestive System
The Liver and Gallbladder
The liver is a large, reddish brown organ that helps with digestion by making bile to break up fat.
Bile is stored in a saclike organ called the gallbladder which squeezes the bile into the small intestine.
The liver also stores excess nutrients until the body is ready to absorb them into the bloodstream.

12. The Liver and the Gallbladder, continued
Chapter 7
Section 1 The Digestive System
The Liver and the Gallbladder, continued

13. Chapter 7 The End of the Line
Section 1 The Digestive System
The End of the Line
Material that can’t be absorbed into the blood is pushed into the large intestine.
The large intestine absorbs most of the water in undigested material and changes the liquid into semisolid waste material called feces, or stool.
Feces are stored in the rectum until they can be expelled.

14. The End of the Line, continued
Chapter 7
Section 1 The Digestive System
The End of the Line, continued
Feces pass to the outside of the body through an opening called the anus.
It takes each of your meals about 24 hours to make this journey through your digestive system.

15. Chapter 7
Section 1 The Digestive System
Chemical Digestion

16. Chapter 7 Concept Mapping
The Digestive and Urinary Systems
Concept Mapping
Use the terms below to complete the concept map on the next slide.
food
digestive system
mechanical digestion
chemical digestion
proteins
enzymes
nutrients

17. Concept Mapping, continued
Chapter 7
The Digestive and Urinary Systems
Concept Mapping, continued

18. Concept Mapping, continued
Chapter 7
The Digestive and Urinary Systems
Concept Mapping, continued

19. Chapter 7
Standardized Test Preparation
1. Wei has been diagnosed with diabetes, so she has to be careful about eating too much sugar. Her body does not produce enough insulin to break down sugars and adequately regulate the amount of glucose in her blood.
Continued on the next slide

20. Chapter 7
Standardized Test Preparation
1. One of Wei’s organs is not working well. Which of the following statements describes that organ?
A. Her pancreas is not making enough insulin.
B. Her salivary glands are breaking down the insulin too quickly.
C. Her smooth muscle tissue is not squeezing out enough insulin.
D. Her stomach acids are reacting with the insulin and neutralizing it.

21. Chapter 7
Standardized Test Preparation
1. One of Wei’s organs is not working well. Which of the following statements describes that organ?
A. Her pancreas is not making enough insulin.
B. Her salivary glands are breaking down the insulin too quickly.
C. Her smooth muscle tissue is not squeezing out enough insulin.
D. Her stomach acids are reacting with the insulin and neutralizing it.

22. Chapter 7
Standardized Test Preparation
5. Jamal’s teacher has made a chart for the class describing the functions of organs of the digestive system. A section from the chart is shown below.

23. Chapter 7 5. continued What information belongs in the missing cells?
Standardized Test Preparation
5. continued
What information belongs in the missing cells?

24. Chapter 7 5. continued What information belongs in the missing cells?
Standardized Test Preparation
5. continued
What information belongs in the missing cells?
1. breaks down toxins
2. makes bile to break up fats
3. insulin

25. Chapter 7
Standardized Test Preparation
6. The digestive system shown in the diagram below is responsible for digesting food so that the body can absorb it. Digestion of food consists of mechanical and chemical digestion.
Continued on the next slide

26. Chapter 7
Standardized Test Preparation
6. Which number indicates the organ that performs most of the chemical digestion of food?
F. 1
G. 2
H. 3
I. 4

27. Chapter 7
Standardized Test Preparation
6. Which number indicates the organ that performs most of the chemical digestion of food?
F. 1
G. 2
H. 3
I. 4

28. Chapter 7
Section 1 The Digestive System

29. Chapter 7
Section 1 The Digestive System