Interest Grabber Section 38 1 Good Food Sense

Interest Grabber Section 38 -1 Good Food Sense Nutrients are molecules that provide the body with energy and materials for growth. Three kinds of nutrients you eat are called fats, proteins, and carbohydrates—terms you may have already heard. Think about what they may mean. 1. Write a brief description of what you think fats, proteins, and carbohydrates are. 2. Which of these three nutrients do you think should make up the largest part of your diet? Which should make up the smallest part? Arrange three nutrients in order starting from the one that you should eat the most to the one that you should eat the least. 3. Why might it be unwise to eat too much of the nutrient you listed last? Go to Section:

Section Outline Section 38 -1 38– 1 Food and Nutrition A. Food and Energy B. Nutrients 1. Water 2. Carbohydrates 3. Fats 4. Proteins 5. Vitamins 6. Minerals C. Nutrition and a Balanced Diet Go to Section:

Concept Map Section 38 -1 Nutrients include Carbohydrates Fats Proteins Vitamins Minerals include are made of are made using include Simple Complex such as Amino acids Fatty Acids Sugars Go to Section: Starches Calcium Glycerol Fat-soluble Watersoluble Iron

Figure 38– 6 Types of Vitamins Section 38 -1 Vitamin Sources Function A (retinol) Yellow, orange, and dark green vegetables; dairy products Important for growth of skin cells; important for night vision D (calciferol) Fish oils, eggs; made by skin when exposed to sunlight; added to dairy products Promotes bone growth; increases calcium and phosphorus absorption E (tocopherol) Green leafy vegetables, seeds, vegetable oils Antioxidant; prevents cellular damage K Green leafy vegetables; made by bacteria that live in human intestine Needed for normal blood clotting B 1 (thiamine) B 2 (riboflavin) Go to Section: Whole grains, pork, legumes, milk Dairy products, meats, vegetables, whole-grain cereal Normal metabolism of carbohydrates Normal growth; part of electron transport chain; energy metabolism

Figure 38– 6 Types of Vitamins Section 38 -1 Vitamin Sources Function Niacin Liver, milk, whole grains, nuts, meats, legumes Important in energy metabolism B 6 (pyridoxine) Whole grains, meats, vegetables Important for amino acid metabolism Pantothenic acid Meats, dairy, whole grains Needed for energy metabolism Folic acid Legumes, nuts, green leafy vegetables, oranges, broccoli, peas, fortified bread and cereal Coenzyme involved in nucleic acid metabolism; prevents neural-tube defects in developing fetuses B 12 (cyanocobalamin) Meats, eggs, dairy products, enriched cereals Coenzyme in nucleic acid metabolism; maturation of red blood cells Go to Section:

Figure 38– 6 Types of Vitamins Section 38 -1 Vitamin Sources Function C (ascorbic acid) Citrus fruits, tomatoes, red or green peppers, broccoli, cabbage, strawberries Maintenance of cartilage and bone; antioxidant; improves iron absorption; important for healthy gums, tissue repair, and wound healing Biotin Legumes, vegetables, meat Coenzyme in synthesis of fat; glycogen formation; amino acid metabolism Choline Egg yolk, liver, grains, legumes Required for phospholipids and neurotransmitters Go to Section:

Figure 38– 7 Types of Minerals Section 38 -1 Mineral Calcium Phosphorus Potassium Sources Diary products; salmon; sardines; kale; tofu; collard greens; legumes Dairy products; meats; poultry; grains Meats; dairy products; many fruits and vegetables; grains Function Bone and tooth formation; blood clotting; nerve and muscle function Bone and tooth formation; acid-base balance Acid-base balance; body water balance; nerve function Chlorine Table salt; processed foods Acid-base balance; formation of gastric juice Sodium Table salt; processed foods Acid-base balance; body water balance; nerve function Magnesium Whole grains; green leafy vegetables Activation of enzymes in protein synthesis Iron Meats; eggs; legumes; whole grains; green leafy vegetables; dried fruit Component of hemoglobin and of electron carriers used in energy metabolism Fluorine Fluoridated drinking water; tea; seafood Maintenance of tooth structure; maintenance of bone structure Iodine Seafood; dairy products; iodized salt Component of thyroid hormones Zinc Go to Section: Meats; seafood; grains Component of certain digestive enzymes

Figure 38– 8 Food Guide Pyramid Section 38 -1 Fats, Oils, and Sweets (use sparingly) Soft drinks, candy, ice cream, mayonnaise, and other foods in this group have relatively few valuable nutrients. Milk, Yogurt, and Cheese Group (2 -3 Servings) Milk and other dairy products are rich in proteins, carbohydrates, vitamins, and minerals. Vegetable Group (3 -5 servings) Vegetables are a low-fat source of carbohydrates, fiber, vitamins, and minerals. Fats Sugars Go to Section: Meat, Poultry, Fish, Dry Beans, Eggs, and Nut Group (2 -3 servings) These foods are high in protein. They also supply vitamins and minerals. Fruit Group (2 -4 servings) Fruits are good sources of carbohydrates, fiber, vitamins and water. Bread, Cereal, Rice and Pasta Group (6 -11 servings) The foods at the base of the pyramid are rich in complex carbohydrates and also provide proteins, fiber, vitamins, and some minerals.

Interest Grabber Section 38 -2 Dinner Is Served Remember the last time you sat down to a dinner of your favorite foods? Recall everything that you did before you swallowed your first bite. 1. Why do you cut up your food? 2. What role do your teeth play in eating? 3. Saliva is the fluid that is found in your mouth. What role do you think it plays in eating? Go to Section:

Section Outline Section 38 -2 38– 2 The Process of Digestion A. The Mouth 1. Teeth 2. Saliva B. The Esophagus C. The Stomach 1. Chemical Digestion 2. Mechanical Digestion D. The Small Intestine Accessory Structures of Digestion E. Absorption in the Small Intestine F. The Large Intestine G. Digestive System Disorders Go to Section:

The Digestive Enzymes Section 38 -2 Site Enzyme Role in Digestion Mouth Salivary amylase Breaks down starches into disaccharides Stomach Pepsin Breaks down proteins into large peptides Small intestine (from pancreas) Amylase Continues the breakdown of starch Trypsin Continues the breakdown of protein Lipase Breaks down fat Maltase, sucrase, lactase Breaks down remaining disaccharides into monosaccharides Peptidase Breaks down dipeptides into amino acids. Small intestine Go to Section:

Figure 38– 10 The Digestive System Section 38 -2 Mouth Pharynx Salivary glands Esophagus Liver Gallbladder (behind liver) Stomach Pancreas (behind stomach) Large intestine Small intestine Rectum Go to Section:

Figure 38– 13 The Liver and the Pancreas Section 38 -2 Liver Gallbladder Duodenum Bile duct Pancreas Pancreatic duct To rest of small intestine Go to Section:

Figure 38– 14 The Small Intestine Section 38 -2 Villus Small Intestine Circular folds Epithelial cells Villi Capillaries Lacteal Vein Artery Go to Section:

Interest Grabber Section 38 -3 Your Body’s Filter Have you ever seen a water-purification system attached to a faucet? This system removes impurities from the water such as arsenic or other chemicals that can be harmful to people. As water passes through the filters contained in the system, the impurities are trapped on the surface of the filters. Eventually, the water that comes out of this purifier is free of the impurities. 1. Your body has its own system for filtering blood. Why might the blood in your body need to be filtered? 2. What organ(s) do you think filters your blood? 3. How do you think the filtered materials leave your body? Go to Section:

Section Outline Section 38 -3 38– 3 The Excretory System A. Functions of the Excretory System B. The Kidneys 1. Kidney Structure 2. Filtration 3. Reabsorption 4. Kidney Stones C. Control of Kidney Function D. Homeostasis by Machine Go to Section:

The Urinary System Section 38 -3 Vein Kidney (Cross Section) Kidney Cortex Medulla Ureter Urinary bladder Urethra Go to Section: Artery

Figure 38– 17 Structure of the Kidneys Section 38 -3 Kidney Nephron Bowman’s capsule Cortex Medulla Renal artery Capillaries Glomerulus Renal vein Ureter Collecting duct Vein To the bladder Artery Loop of Henle Go to Section: To the ureter

The Nephron Section 38 -3 Reabsorption Filtration Most filtration occurs in the glomerulus. Blood pressure forces water, salt, glucose, amino acids, and urea into Bowman’s capsule. Proteins and blood cells are too large to cross the membrane; they remain in the blood. The fluid that enters the renal tubules is called the filtrate. Go to Section: As the filtrate flows through the renal tubule, most of the water and nutrients are reabsorbed into the blood. The concentrated fluid that remains is called urine.

Figure 38– 19 Kidney Dialysis Section 38 -3 Blood in tubing flows through dialysis fluid Blood pump Vein Artery Used dialysis fluid Shunt Air detector Go to Section: Dialysis machine Fresh dialysis fluid Compressed air

Videos Click a hyperlink to choose a video. Human Digestion Kidney Function

Video 1 Human Digestion Click the image to play the video segment.

Video 2 Kidney Function Click the image to play the video segment.

Go Online Interactive test For links on nutrition, go to www. scilinks. org and enter the Web Code as follows: cbn-0381. For links on digestion, go to www. scilinks. org and enter the Web Code as follows: cbn-0382. For links on the excretory system, go to www. scilinks. org and enter the Web Code as follows: cbn-0383.

Interest Grabber Answers 1. Write a brief description of what you think fats, proteins, and carbohydrates are. Accept all reasonable descriptions. You may wish to have students revisit their descriptions after completing this section. 2. Which of these three nutrients do you think should make up the largest part of your diet? Which should make up the smallest part? Arrange three nutrients in order starting from the one that you should eat the most to the one that you should eat the least. Carbohydrate, protein, fat 3. Why might it be unwise to eat too much of the nutrient you listed last? Possible answer: The body needs only small amounts of fats; fats contain more Calories than the other nutrients do.

Interest Grabber Answers 1. Why do you cut up your food? To make pieces small enough to fit in the mouth 2. What role do your teeth play in eating? They crush the food so it is small enough to be swallowed. 3. Saliva is the fluid that is found in your mouth. What role do you think it plays in eating? Students will likely say that it moistens the food so it is easier to swallow. Students may also be aware that saliva contains a digestive enzyme.

Interest Grabber Answers 1. Your body has its own system for filtering blood. Why might the blood in your body need to be filtered? In order to remove from the blood any impurities that could be harmful 2. What organ(s) do you think filters your blood? Possible answer: kidneys 3. How do you think the filtered materials leave your body? Possible answer: as urine

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