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 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
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
include
Simple
Complex
such as
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
B1 (thiamine)
Whole grains, pork, legumes,
milk
Normal metabolism of
carbohydrates
B2 (riboflavin)
Dairy products, meats,
vegetables, whole-grain cereal
Normal growth; part of electron
transport chain; energy
metabolism
Go to
Section:
Figure 38–6 Types of Vitamins
Section 38-1
Vitamin
Sources
Function
Niacin
Liver, milk, whole grains, nuts,
meats, legumes
Important in energy metabolism
B6 (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
B12
(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
Bile duct
Gallbladder
Pancreas
Pancreatic duct
Duodenum
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
Capillaries
Glomerulus
Medulla
Renal
artery
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 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
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