HBHD 13e Ch20

Copyright © 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins
Chapter 20
Metabolism, Nutrition,
and Body Temperature

Copyright © 2015 Wolters Kluwer • All Rights Reserved
Overview

Key Terms
anabolism glycogen metabolic rate
basal metabolism glycolysis mineral
catabolism hypothalamus oxidation
cellular respiration hypothermia pyrogen
fever kilocalorie vitamin
glucose malnutrition

Metabolism
Learning Objectives
1. Differentiate between catabolism
and anabolism.
2. Differentiate between the anaerobic
and aerobic phases of glucose
catabolism and give the end products
and the relative amount of energy
released by each.
3.Define metabolic rate and name six
factors that affect it.
4. Explain how carbohydrates,
fats, and proteins are metabolized for
energy.
5. Compare the energy contents of
carbohydrates, fats, and proteins.

Nutritional Guidelines
Learning Objectives
6.List the recommended percentages of
carbohydrate, fat, and protein in the diet.
7. Distinguish between simple and
complex carbohydrates, giving examples
of each.
8.Compare saturated and unsaturated
fats.
9. Define essential amino acid.
10. Explain the roles of minerals and
vitamins in nutrition and give examples
of each.
11. List six adverse effects of alcohol
consumption.

Nutritional Disorders
Learning Objective
12. Describe four nutritional
disorders.

Body Temperature
Learning Objectives
13. Explain how heat is produced
and lost in the body.
14. Describe the role of the hypothalamus
in regulating body temperature.
15. Explain the role of fever in disease.
16. Describe responses to excessive heat
and cold.

Case Study
Learning Objective
17. Using the case study
and the text, define
anorexia nervosa, and list
some of its adverse effects.

Word Anatomy
Learning Objective
18. Show how word parts are used to build words
related to metabolism, nutrition, and body
temperature.

Metabolism
Types of Metabolic Activities
•Catabolism
– Breaks down complex compounds into simpler
compounds
•Anabolism
– Builds simple compounds into needed substances

Metabolism (cont.)
Cellular Respiration
•Glucose catabolism: anaerobic phase (glycolysis)
– Location: Cytoplasm
– Yield: 2 ATP per glucose molecule
– End product: Pyruvic acid
•Glucose catabolism: Aerobic phase
– Location: Mitochondria
– Yield: 32 ATP per glucose molecule
– End products: CO2 and H2O

Metabolism (cont.)
Cellular Respiration (cont.)
•Cellular respiration of fatty acids and amino acids
– Oxidized to generate energy through aerobic
mechanisms

Figure 20-1 Cellular respiration.
What does pyruvic acid produce when it is metabolized
anaerobically? What does it produce when metabolized
completely using oxygen?

Metabolism (cont.)
Metabolic Rate
•Rate at which cellular respiration converts nutrients into
ATP
•Decreases with age
•Basal metabolism
•Measured in kilocalories (kcal)

Metabolism (cont.)
Nutrient Metabolism
•Carbohydrates
– Glucose is the major energy source for cells.
– Glycogen is storage form of carbohydrates.
• Glycogen broken down to yield glucose.
– Excess glucose converted to fat and stored.
•Fats
– Fatty acids can be used for energy.
– Fatty acids are a highly concentrated energy source.
– Store excess calories.

Metabolism (cont.)
Nutrient Metabolism (cont.)
•Proteins
– No specialized storage forms for protein.
– Specific proteins are synthesized to meet specific
body needs.

Metabolism (cont.)
✓
Checkpoints
20-1 What are the two types of activities that make
up metabolism?
20-2 What name is given to the series of cellular
reactions that releases energy from nutrients?
20-3 What is the organic end product of glycolysis?
20-4 What element is required for aerobic cellular
respiration but not for glycolysis?
20-5 What is removed from amino acids before they are
metabolized for energy?

Nutritional Guidelines (cont.)
Percentage of Calories in Daily Diet
•Carbohydrate: 55% to 60%
•Fat: 30% or less
•Protein: 15% to 20%

Carbohydrates
•Types
– Simple sugars (monosaccharides)
– Complex carbohydrates (polysaccharides)
• Starches
• Fibers

Fats
•Moderate amounts are necessary.
•Essential fatty acids:
–Linoleic acid
–Alpha-linolenic acid

Fats (cont.)
•Saturated and unsaturated fats
– Saturated fats
• Most are from animal sources.
• Solid at room temperature.
– Unsaturated fats
• Derived from plants
• Liquid at room temperature

Figure 20-2 Saturated and
unsaturated fats.

Proteins
•Essential amino acids
– Most animal proteins supply all of the essential
amino acids (complete).
•Nonessential amino acids
– Can be synthesized by the body

Figure 20-3 Combining foods to obtain the essential
amino acids.

Minerals and Vitamins
•Minerals are chemical elements necessary for:
– Body structure
– Fluid balance
– Muscle contraction
– Nerve impulse conduction
– Blood clotting

Minerals and Vitamins (cont.)
•Vitamins are complex organic substances.
– Water soluble
– Fat soluble
•Some are antioxidants.
– Stabilize free radicals

Minerals and Vitamins (cont.)
•Vitamin and mineral supplements
– Supplements are controversial.
– Some populations may benefit from them.
– Some vitamins cause toxic effects when taken in
excess.

USDA Guidelines
•MyPlate updated guidelines in 2011
•ChooseMyPlate.gov
– Guidelines for individual variation

Figure 20-4 USDA dietary guidelines.

Alcohol
•Not a nutrient
•Interferes with metabolism
•Should be consumed only in moderation

✓
Checkpoints
20-6 What is the term for how rapidly a food raises the
blood glucose level?
20-7 What is meant when an amino acid or a fatty acid is
described as essential?
20-8 What is the difference between saturated and
unsaturated fats?
20-9 What is the difference between vitamins and
minerals?
20-10 How much pure alcohol can the average person
metabolize per hour?

Nutritional Disorders (cont.)
Food Allergies
•Allergens can be food or food additives.
•Allergic reactions usually involve the:
– Skin
– Respiratory tract
– Gastrointestinal tract
•Reactions can be fatal in extremely sensitive individuals.
Nonallergic Adverse Food Reactions
– Result of enzyme deficiency
– Gastrointestinal symptoms

Malnutrition
•Can occur from missing nutrients or eating too much of
wrong foods
•Protein–energy malnutrition (PEM)
•Marasmus
•Kwashiorkor

Figure 20-5 Effects of kwashiorkor.

Weight Control
•Body mass index (BMI)
•Overweight and obesity
– Measured by body mass index (BMI)
• Overweight is BMI of 25 to 30.
• Obese is BMI greater than 30.

Weight Control (cont.)
•Underweight
– BMI less than 18.5
– May result from:
• Eating disorders (anorexia, bulimia)
• Rapid growth
• Allergies
• Illness
• Psychological factors

Figure 20-6 Calculation of body mass index (BMI).
What is the BMI of a man 5′10″ in height who weighs 170
pounds? (Round off to one decimal place.)

✓
Checkpoints
20-11 What condition results from lack of any specific
nutrient in the diet?
20-12 What does the abbreviation BMI stand for?
20-13 What term applies to any chronic loss of appetite?

Nutrition and Aging
• Nutritional deficiencies may develop.
• Senses of smell and taste decline.
• Ability to synthesize vitamin D and calcium declines.
• Medications may interfere with appetite and absorption.

Body Temperature (cont.)
• Heat is by-product of chemical activities in body tissues.
• Regulatory devices keep body temperature constant
within narrow limits.

Heat Production
Heat production directly correlates with tissue activity.
•Muscle cell activity and heat production increase with
exercise.
•Food intake augments heat production.
•Hormone production.

Heat Loss
•Mechanisms of heat loss :
– Radiation
– Convection
– Evaporation
– Conduction
•Prevention of heat loss
– Volume of tissue compared with amount of skin
surface is a factor.
– Natural insulation.

Figure 20-7 Mechanisms of heat loss.
What will happen in (B) if the fan speed is increased?
What will happen in (C) as environmental humidity
increases?

Temperature Regulation
Integrating center for heat regulation is the hypothalamus.
•Responses to cold conditions
– Vasoconstriction
– Shivering
– Behavioral responses
•Responses to hot conditions
– Vasodilation
– Evaporation of sweat

Figure 20-8 Thermoregulation.
Is blood flow in the skin higher under cold conditions or hot
conditions?

Temperature Regulation (cont.)
•Age factors
– Newborns and elderly
• Reduced ability to produce heat
• Reduced ability to regulate overheating
• Should be protected from extreme temperatures
•Normal body temperature
– Normal range is 36.2°C to 37.6°C (97°F to 100°F).
– Varies with time of day.
– Varies by body part.

Fever
•Higher than normal body temperature (febrile)
•Causes:
– Infection
– Malignancies
– Brain injuries
– Toxic reactions
– Vaccine reactions
– Central nervous system diseases

Fever (cont.)
•Increase in metabolism proportional to the fever’s
intensity
•Crisis
– Profuse perspiration
– Muscular relaxation
– Vasodilation
•Lysis
•Antipyretic

Responses to Excessive Heat
•Heat cramps
– Localized muscle cramping
•Heat exhaustion
– Heat retention and fluid loss
•Heat stroke
– A medical emergency that can be fatal

Responses to Excessive Cold
•Hypothermia
– Excessively low body temperature
– Cellular metabolism slows
•Frostbite
– Can cause permanent local tissue damage.
– Likely areas are face, ears, extremities.
– Young and elderly and those with circulatory
disorders are susceptible to cold injuries.

✓
Checkpoints
20-14 What part of the brain is responsible for regulating
body temperature?
20-15 What does an antipyretic drug do?
20-16 What change occurs in cutaneous blood vessels
under cold conditions? Under hot conditions?
20-17 What is the term for excessively low body
temperature?

Case Study (cont.)
Anorexia Nervosa
•Psychological disorder
•Desire to be excessively thin
– Starvation
•Body resorts to breaking down proteins to produce
energy
•Results of the unhealthy eating behavior:
– Loss of bone protein
– Loss of cardiac muscle
– Loss of skeletal muscle protein

Word Anatomy
Learning Objective
18. Show how word parts are used to build words related
to metabolism, nutrition, and body temperature.

Word Anatomy (cont.)

HBHD 13e Ch20

Recommended

Recommended

More Related Content

Viewers also liked

Viewers also liked (13)

Similar to HBHD 13e Ch20

Similar to HBHD 13e Ch20 (20)

Recently uploaded

Recently uploaded (20)

HBHD 13e Ch20