Go to Section: Interest Grabber Good Food Sense Nutrients are molecules that provide the body with energy and materials for growth. Three kinds of nutrients.

Go to Section:

Interest Grabber

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.

Section 38-1

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 the 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

38–1 Food and NutritionA. Food and Energy

B. Nutrients

1. Water

2. Carbohydrates

3. Fats

4. Proteins

5. Vitamins

6. Minerals

C. Nutrition and a Balanced Diet

Section 38-1

Go to Section:

include

include

such as such as

are made of include

Concept Map

includeare made using

Section 38-1

Nutrients

Carbohydrates Fats MineralsProteins Vitamins

Simple ComplexAmino acids

Calcium Iron

Fatty Acids Glycerol

Sugars Starches Fat-solubleWater-soluble

Go to Section:

Figure 38–6 Types of Vitamins

Vitamin

A (retinol)

D (calciferol)

E (tocopherol)

K

B1 (thiamine)

B2 (riboflavin)

Vitamin

A (retinol)

D (calciferol)

E (tocopherol)

K

B1 (thiamine)

B2 (riboflavin)

Sources

Yellow, orange, and dark green vegetables; dairy products

Fish oils, eggs; made by skin when exposed to sunlight; added to dairy products

Green leafy vegetables, seeds, vegetable oils

Green leafy vegetables; made by bacteria that live in human intestine

Whole grains, pork, legumes, milk

Dairy products, meats, vegetables, whole-grain cereal

Sources

Yellow, orange, and dark green vegetables; dairy products

Fish oils, eggs; made by skin when exposed to sunlight; added to dairy products

Green leafy vegetables, seeds, vegetable oils

Green leafy vegetables; made by bacteria that live in human intestine

Whole grains, pork, legumes, milk

Dairy products, meats, vegetables, whole-grain cereal

Function

Important for growth of skin cells; important for night vision

Promotes bone growth; increases calcium and phosphorus absorption

Antioxidant; prevents cellular damage

Needed for normal blood clotting

Normal metabolism of carbohydrates

Normal growth; part of electron transport chain; energy metabolism

Function

Important for growth of skin cells; important for night vision

Promotes bone growth; increases calcium and phosphorus absorption

Antioxidant; prevents cellular damage

Needed for normal blood clotting

Normal metabolism of carbohydrates

Normal growth; part of electron transport chain; energy metabolism

Section 38-1

Go to Section:

Figure 38–6 Types of Vitamins

Vitamin

Niacin

B6 (pyridoxine)

Pantothenic acid

Folic acid

B12 (cyanocobalamin)

Vitamin

Niacin

B6 (pyridoxine)

Pantothenic acid

Folic acid

B12 (cyanocobalamin)

Sources

Liver, milk, whole grains, nuts, meats, legumes

Whole grains, meats, vegetables

Meats, dairy, whole grains

Legumes, nuts, green leafy vegetables, oranges, broccoli, peas, fortified bread and cereal

Meats, eggs, dairy products, enriched cereals

Sources

Liver, milk, whole grains, nuts, meats, legumes

Whole grains, meats, vegetables

Meats, dairy, whole grains

Legumes, nuts, green leafy vegetables, oranges, broccoli, peas, fortified bread and cereal

Meats, eggs, dairy products, enriched cereals

Function

Important in energy metabolism

Important for amino acid metabolism

Needed for energy metabolism

Coenzyme involved in nucleic acid metabolism; prevents neural-tube defects in developing fetuses

Coenzyme in nucleic acid metabolism; maturation of red blood cells

Function

Important in energy metabolism

Important for amino acid metabolism

Needed for energy metabolism

Coenzyme involved in nucleic acid metabolism; prevents neural-tube defects in developing fetuses

Coenzyme in nucleic acid metabolism; maturation of red blood cells

Section 38-1

Go to Section:

Figure 38–6 Types of Vitamins

Vitamin

C (ascorbic acid)

Biotin

Choline

Vitamin

C (ascorbic acid)

Biotin

Choline

Sources

Citrus fruits, tomatoes, red or green peppers, broccoli, cabbage, strawberries

Legumes, vegetables, meat

Egg yolk, liver, grains, legumes

Sources

Citrus fruits, tomatoes, red or green peppers, broccoli, cabbage, strawberries

Legumes, vegetables, meat

Egg yolk, liver, grains, legumes

Function

Maintenance of cartilage and bone; antioxidant; improves iron absorption; important for healthy gums, tissue repair, and wound healing

Coenzyme in synthesis of fat; glycogen formation; amino acid metabolism

Required for phospholipids and neurotransmitters

Function

Maintenance of cartilage and bone; antioxidant; improves iron absorption; important for healthy gums, tissue repair, and wound healing

Coenzyme in synthesis of fat; glycogen formation; amino acid metabolism

Required for phospholipids and neurotransmitters

Section 38-1

Go to Section:

Figure 38–7 Types of Minerals

Section 38-1

Mineral

Calcium

Phosphorus

Potassium

Chlorine

Sodium

Magnesium

Iron

Fluorine

Iodine

Zinc

Sources

Diary products; salmon; sardines;

kale; tofu; collard greens; legumes

Dairy products; meats; poultry; grains

Meats; dairy products; manyfruits and vegetables; grains

Table salt; processed foods

Table salt; processed foods

Whole grains; green leafy vegetables

Meats; eggs; legumes; whole grains; green leafy vegetables; dried fruit

Fluoridated drinking water; tea; seafood

Seafood; dairy products; iodized salt

Meats; seafood; 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

Acid-base balance; formation of gastric juice

Acid-base balance; body water balance; nerve function

Activation of enzymes in protein synthesis

Component of hemoglobin and of electron carriers used in energy metabolism

Maintenance of tooth structure; maintenance of bone structure

Component of thyroid hormones

Component of certain digestive enzymes

Go to Section:

FatsSugars

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.

Meat, Poultry, Fish, Dry Beans, Eggs, and Nut Group(2-3 servings)These foods are high in protein. They also supply vitamins and minerals.

Vegetable Group(3-5 servings)Vegetables are a low-fat source of carbohydrates,fiber, vitamins, and minerals.

Fruit Group(2-4 servings)Fruits are good sources of carbohydrates, fiber, vitaminsand water.

Bread, Cereal, Riceand 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.

Figure 38–8 Food Guide Pyramid

Section 38-1

Go to Section:

Interest Grabber

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.

Section 38-2

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

38–2 The Process of DigestionA. 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

Section 38-2

Go to Section:

The Digestive Enzymes

Site

Mouth

Stomach

Small intestine(from pancreas)

Small intestine

Site

Mouth

Stomach

Small intestine(from pancreas)

Small intestine

EnzymeEnzyme Role in DigestionRole in Digestion

Section 38-2

Salivary amylase

Pepsin

Amylase

Trypsin

Lipase

Maltase, sucrase, lactase

Peptidase

Breaks down starches into disaccharides

Breaks down proteins into large peptides

Continues the breakdown of starch

Continues the breakdown of protein

Breaks down fat

Breaks down remaining disaccharides into monosaccharides

Breaks down dipeptides into amino acids.

Go to Section:

Mouth

Salivary glands

Stomach

Pancreas (behind stomach)Large intestine

Small intestine

Rectum

Gallbladder (behind liver)

Liver

Esophagus

Pharynx

Figure 38–10 The Digestive System

Section 38-2

Go to Section:

Liver

Gallbladder

Duodenum

Bile duct

Pancreas

Pancreatic duct

To rest of small intestine

Figure 38–13 The Liver and the Pancreas

Section 38-2

Go to Section:

Small Intestine Villus

Circular folds

Villi

Epithelial cells

Capillaries

Lacteal

Vein

Artery

Figure 38–14 The Small Intestine

Section 38-2

Go to Section:

Interest Grabber

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.

Section 38-3

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

38–3 The Excretory SystemA. 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

Section 38-3

Go to Section:

Kidney (Cross Section)

Cortex

Medulla

Vein Artery

Kidney

Ureter

Urinary bladder

Urethra

The Urinary System

Section 38-3

Go to Section:

Kidney Nephron

Cortex

Medulla Renal artery

Renal vein

Ureter

To the bladder

Bowman’s capsule

Glomerulus

Capillaries

Collecting duct

To the ureter

Loop of Henle

Artery

Vein

Figure 38–17 Structure of the Kidneys

Section 38-3

Go to Section:

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.

Reabsorption

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.

The Nephron

Section 38-3

Go to Section:

Vein

Artery

Shunt

Air detector Dialysis machine

Blood pump

Blood in tubing flows through dialysis fluid

Used dialysis fluid

Compressed air

Fresh dialysis

fluid

Figure 38–19 Kidney Dialysis

Section 38-3

Videos

Click a hyperlink to choose a video.

Human Digestion

Kidney Function

Click the image to play the video segment.

Video 1

Human Digestion

Click the image to play the video segment.

Video 2

Kidney Function

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 the 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

This slide is intentionally blank.