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BC Science 8 CH02 11/5/06 11:39 AM Page 26 Name Section Date 2.2 The Digestive and Excretory Systems Summary Textbook pages 64–81 Before You Read Many structures and organs work together to digest food. What parts of your body do you think play a role? Write your thoughts on the lines below. _______________________________________________________________________________________ _______________________________________________________________________________________ ◆ ✏ Mark the Text Create an Outline Make an outline of this section. Use the headings in the reading as a starting point. Include the terms that you think are important. ✔ ● Reading Check 1. What are the five nutrients? What makes up the food you eat? The food and liquids that you take into your body have nutrients. Nutrients are substances that supply the energy and materials your body needs. Your body uses nutrients to grow, develop, and repair itself. Water is not a nutrient but your body needs water to transport the nutrients and wastes. There are five types of nutrients: ◆ Carbohydrates are the body’s quickest source of energy. Examples: pasta and brown rice ◆ Proteins help to build muscles, skin, hair, and nails. Examples: fish and nuts ◆ Fats build cell membranes and are stored for energy. Examples: butter and oil ◆ Vitamins help keep your body healthy and strong. Examples: vitamin D from sunlight and vitamin C from oranges ◆ Minerals help keep your body healthy and strong. Examples: iron from leafy vegetables and calcium ✔ from milk ● ___________________ ___________________ ___________________ ___________________ ___________________ How are nutrients from food digested? The process of digestion breaks down nutrients, absorbs them, and stores some of them for later use. The digestive system also removes solid wastes that the body is not able to use. There are four stages of digestion. Read about them in the table on the next page. 26 MHR • Section 2.2 The Digestive and Excretory Systems © 2006 McGraw-Hill Ryerson Limited BC Science 8 CH02 11/5/06 11:39 AM Page 27 Section Name 2.2 Date Summary continued The four stages of digestion What parts of the digestive system are involved? What happens? 1. ingesting mouth • Food is taken into the mouth. 2. digesting mouth esophagus stomach small intestine • Teeth grind food into smaller pieces. • Saliva mixes with the food pieces. • Muscles in the esophagus push the food down into the stomach. • The food is covered with gastric juice, which is a mixture of strong hydrochloric acid, mucus, and enzymes that break down the food into a liquid form. Enzymes are proteins that speed up digestion. The thick, slippery mucus protects the stomach lining from the strong acid. • The liquid food leaves the stomach and enters the first part of the small intestine, where it is broken down into small nutrient particles. Tubes connect to other organs, such as the pancreas, liver, and gall bladder, that produce substances to help digest the food. 3. absorbing small intestine large intestine • Nutrients are absorbed in the rest of the small intestine. • The small intestine is lined with many villi. Villi are fold-like structures that increase the surface available to absorb nutrients. • Undigested food leaves the small intestine and enters the large intestine, where water and some minerals are absorbed. 4. eliminating rectum anus ✔ ● Reading Check 2. What are the four stages of digestion? • Any undigested material (feces) is stored in the rectum. • The feces leave the body through the anus. ___________________ ● ✔ How is liquid waste removed from the body? ___________________ ___________________ ___________________ Excretion is the job of the excretory system. Excretion removes liquid wastes and gas wastes from the body. Your kidneys filter liquid wastes from your blood and store the wastes (urine) in your bladder until they are flushed from the body. © 2006 McGraw-Hill Ryerson Limited Section 2.2 The Digestive and Excretory Systems • MHR 27 BC Science 8 CH02 11/5/06 11:39 AM Page 28 Name Date Cloze Activity Section 2.2 Use with textbook pages 64–69. Know your nutrients Vocabulary brown rice butter calcium circulatory digestive energy excretory fish gastric juice iron nuts oil pasta protein respiratory villi vitamin C vitamin D Use the terms in the vocabulary box to fill in the blanks. Each term may be used more than once. You will not need to use every term. 1. Carbohydrates are the body’s fastest source of _________________________________. 2. Examples of foods containing carbohydrates are ________________________________ and ________________________________________________________________________. 3. ________________________________________ help build muscles, skin, hair, and nails. Examples of foods containing this nutrient are __________________________________ and _______________________________________________________________________. 4. Fats are used to build _______________________________________ and can be stored by the body for _____________________________________________________________. 5. Examples of foods containing fats are __________________________________________ and _______________________________________________________________________. 6. Two common minerals are ____________________________________________________ and ________________________________________________________________________. 7. Two common vitamins are ____________________________________________________ and ________________________________________________________________________. 8. The ____________________________________________ system breaks down nutrients, absorbs them, and stores some of them for later use. 9. The ________________________________________ system removes liquid wastes and gas wastes from the body. 28 MHR • Section 2.2 The Digestive and Excretory Systems © 2006 McGraw-Hill Ryerson Limited BC Science 8 CH02 11/5/06 11:39 AM Page 29 Name Date Illustrating Concepts Section 2.2 Use with textbook page 70. Stages of digestion Use a different colour for each stage of digestion. Colour in the areas of the digestive system where each of the stages occurs. Be sure to label each section. © 2006 McGraw-Hill Ryerson Limited Section 2.2 The Digestive and Excretory Systems • MHR 29 BC Science 8 CH02 11/5/06 11:39 AM Page 30 Name Vocabulary Section 2.2 Date Use with textbook pages 71–76. Looking inside digestion and excretion Match each Term on the left with the best Descriptor on the right. Each Descriptor may be used only once. You will not need to use all the Descriptors. Term Descriptor 1. ______ feces A. a liquid in the stomach 2. ______ urine B. fold-like structures that absorb nutrients in the small intestine 3. ______ villi C. mixes with food pieces in the mouth 4. ______ gastric juice D. undigested material leaves the body through this 5. ______ enzymes E. undigested material stored in the rectum 6. ______ mucus F. proteins that speed up digestion 7. ______ anus G. liquid wastes stored in your bladder 8. ______ blood H. kidneys filter liquid wastes from this 9. ______ saliva 10. ______ nutrients I. a thick, slippery substance that protects the lining of the stomach J. the liquid food that is broken down into nutrients K. substances that supply energy 30 MHR • Section 2.2 The Digestive and Excretory Systems © 2006 McGraw-Hill Ryerson Limited BC Science 8 CH02 11/5/06 11:39 AM Page 31 Name Assessment Section 2.2 Date Use with textbook pages 64–80. 6. The part of the digestive system in which nutrients are absorbed includes the The digestive and excretory systems A. stomach and esophagus B. small intestine and large intestine C. stomach and small intestine Circle the letter of the best answer. 1. A nutrient used for quick energy is a D. all of the above 7. The part of the digestive system that ingests food is the A. protein B. carbohydrate A. mouth C. fat B. stomach D. mineral C. esophagus 2. A nutrient used to build cell membranes is a A. protein D. all of the above 8. The part of the digestive system that digests food is the B. carbohydrate C. fat A. mouth and esophagus D. vitamin B. stomach 3. A nutrient used to build muscle, skin, hair, and nails is a C. small intestine D. all of the above A. protein Match each Term on the left with the best Descriptor on the right. Each Descriptor may be used only once. B. carbohydrate C. mineral D. vitamin 4. Iron and calcium are examples of A. minerals B. carbohydrates C. fats D. vitamins 5. The part of the digestive system in which undigested material is eliminated includes the A. rectum and anus B. pancreas, liver, and gall bladder C. large intestine Term Descriptor 9. ______ digestion 10. ______ excretion 11. ______ gastric juice 12. ______ mucus 13. ______ nutrients 14. ______ villi A. thick slippery substance that protects the stomach lining B. breaks down, absorbs, and stores nutrients C. liquid in stomach D. fold-like structures that absorb nutrients E. mixes with food pieces in mouth F. substances that supply energy G. removes wastes D. none of the above © 2006 McGraw-Hill Ryerson Limited Section 2.2 The Digestive and Excretory Systems • MHR 31