Digestive System Worksheet
Digestive System Worksheet
Digestive System Worksheet
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Lesson Summary
Functions of the Digestive System The digestive system converts food into small molecules
that can be used by body cells. Food is processed by the digestive system in four phases: ingestion, digestion, absorption, and elimination. Ingestion is the process of putting food into your mouth. Mechanical digestion is the physical breakdown of large pieces of food into smaller pieces. During chemical digestion, enzymes break down food into molecules the body can use. Food molecules are absorbed into the circulatory system by cells in the small intestine. Materials the body cannot digest travel through the large intestine and are eliminated as feces.
The Process of Digestion During digestion, food travels through the mouth, esophagus, stomach,
and small intestine. Mechanical digestion begins as teeth tear and grind food. Saliva contains amylase, an enzyme that breaks down starches into sugars. This begins the process of chemical digestion. Once food is chewed, it is pushed into the pharynx. The tube leading from the pharynx to the stomach is called the esophagus. Contractions of smooth muscles, called peristalsis, move food through the esophagus to the stomach, a large muscular sac that continues digestion. Glands in the stomach lining release hydrochloric acid and the enzyme pepsin, which breaks proteins into smaller polypeptide fragments. Contractions of stomach muscles churn the stomach contents, which forms chyme, a mixture with an oatmeal-like consistency. As chyme moves out of the stomach, it enters the duodenum, the uppermost portion of the small intestine. Here, digestive fluids from the pancreas, liver, and lining of the duodenum are added to the chyme.
Absorption and Elimination Most nutrients from food are absorbed by the small intestine. The
large intestine absorbs water and prepares waste for elimination from the body. The small intestine has fingerlike projections ( villi) that are covered with microvilli, which absorb nutrients. Most nutrients are absorbed into the blood, but fats are absorbed into the lymph. When chyme leaves the small intestine, it enters the large intestine, or colon. The large intestine absorbs water and some vitamins that are produced by bacteria in the large intestine. The remaining waste material leaves the body through the anus.
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5. Where does chemical digestion begin? A. the stomach C. the mouth B. the small intestine D. the esophagus 6. Saliva eases the passage of food through the digestive system and contains A. amylase. C. sodium bicarbonate. B. pepsin. D. bile. 7. Which is the correct order of passage of food through the digestive system? A. mouth, stomach, esophagus, large intestine, small intestine B. mouth, stomach, esophagus, small intestine, large intestine C. mouth, esophagus, stomach, small intestine, large intestine D. mouth, esophagus, stomach, large intestine, small intestine 8. Which of the following is not a role of the pancreas? A. produces sodium bicarbonate B. produces bile C. produces hormones that regulate blood sugar D. produces enzymes that break down carbohydrates, proteins, lipids, and nucleic acids
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Active Site
Enzyme
Effect on Food
Breaks down starches into disaccharides
Pepsin Small intestine (released from pancreas) Trypsin Breaks down fat Small intestine Maltase, sucrase, lactase Continues the breakdown of starch
THINK VISUALLY 10. Draw and label the digestive system. Include the salivary glands, mouth, epiglottis, esophagus, stomach, liver, gallbladder, small intestine, and large intestine.
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11. The folded surface and fingerlike projections of the surface area for absorption of nutrient molecules. 12. The fingerlike projections are called 13. Capillaries in the villi absorb the products of 14. Fats and fatty acids are absorbed by 15. In some animals, the . . and
provide a large
digestion.
16. Once chyme leaves the small intestine, it enters the large intestine, or
17. The small intestine is longer than the large intestine. How did the large intestine get its name?
19. What happens to waste materials when they leave the colon?
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5. Where does chemical digestion begin? A. the stomach C. the mouth B. the small intestine D. the esophagus 6. Saliva eases the passage of food through the digestive system and contains A. amylase. C. sodium bicarbonate. B. pepsin. D. bile. 7. Which is the correct order of passage of food through the digestive system? A. mouth, stomach, esophagus, large intestine, small intestine B. mouth, stomach, esophagus, small intestine, large intestine C. mouth, esophagus, stomach, small intestine, large intestine D. mouth, esophagus, stomach, large intestine, small intestine 8. Which of the following is not a role of the pancreas? A. produces sodium bicarbonate B. produces bile C. produces hormones that regulate blood sugar D. produces enzymes that break down carbohydrates, proteins, lipids, and nucleic acids
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Class
Date
Active Site
Mouth Stomach
Enzyme
Amylase
Effect on Food
Breaks down starches into disaccharides Proteins amino acids
Pepsin Amylase
Trypsin Lipase Breaks down fat Converts disaccharides to monosaccharides Breaks down dipeptides into amino acids
Small intestine
THINK VISUALLY 10. Draw and label the digestive system. Include the salivary glands, mouth, epiglottis, esophagus, stomach, liver, gallbladder, small intestine, and large intestine.
474Name
Class
Date
11. The folded surface and fingerlike projections of the small intestine provide a large surface area for absorption of nutrient molecules. 12. The fingerlike projections are called villi and microvilli 13. Capillaries in the villi absorb the products of physical 14. Fats and fatty acids are absorbed by lymph vessel 15. In some animals, the large intestine . . . and chemical digestion.
16. Once chyme leaves the small intestine, it enters the large intestine, or
17. The small intestine is longer than the large intestine. How did the large intestine get its name? The diameter is bigger 18. What is the primary function of the large intestine? Water absorbtion 19. What happens to waste materials when they leave the colon? Expelled as feces