1. Chapter 20: Metabolism, Nutrition, and Body Temperature

2. Overview

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

4. Metabolism Learning Outcomes
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.

5. Metabolism
Types of Metabolic Activities
Catabolism
Anabolism

6. Metabolism Cellular Respiration
Anaerobic glucose catabolism; glycolysis
Location: Cytoplasm
Yield:
End product:
Aerobic glucose catabolism
Location: Mitochondria
End products:

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

8. Metabolism Learning Outcomes
3. Define metabolic rate and name several factors that affect the metabolic rate.
4. Explain how carbohydrates, fats, and proteins are metabolized for energy.
5. Compare the energy contents of fats, proteins, and carbohydrates.
6. Define essential amino acid.
7. Explain the roles of minerals and vitamins in nutrition and give examples of each.

9. Metabolism Metabolic Rate Decreases with age
Measured in kilocalories (kcal)

10. Metabolism The Use of Nutrients for Energy
Glucose is main source of energy
Other energy sources

11. Metabolism
Minerals
They are necessary for
Blood clotting

12. Metabolism Vitamins Vitamins are Water soluble Fat soluble
Some are antioxidants.

13. ✓ Metabolism 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 are the two main energy sources for cells?
20-4 What is meant when an amino acid or a fatty acid is described as essential?
20-5 What is the difference between vitamins and minerals? 13

14. Nutritional Guidelines
Learning Outcomes
8. List the recommended percentages of carbohydrate, fat, and protein in the diet.
9. Distinguish between simple and complex carbohydrates, giving examples of each.
10. Compare saturated and unsaturated fats.
11. List some adverse effects of alcohol consumption.

15. Nutritional Guidelines
Percentage of Calories in Daily Diet
Carbohydrate:
Fat:
Protein:

16. Nutritional Guidelines
Carbohydrates
Types
Starches
Plant fiber

17. Nutritional Guidelines
Carbohydrates
Diet should be mainly complex, naturally occurring carbohydrates
Normal blood glucose range 85–125 mg/dL
Glycemic effect measures how rapidly food raises blood glucose level, stimulates release of insulin

18. Nutritional Guidelines
Fats
Types
Most are from animal sources
Solid at room temperature
Derived from plants
Liquid at room temperature

19. Figure 20-2 Saturated and unsaturated fats.19

20. Nutritional Guidelines
Proteins
Most animal proteins supply all essential amino acids (complete).
Most vegetable proteins lack one or more essential amino acids (incomplete).

21. Figure 20-3 Combining foods to obtain the essential amino acids.21

22. Nutritional Guidelines
Vitamin and Mineral Supplements
Supplements are controversial.
Some populations may benefit from them.
Some vitamins cause toxic effects when taken in excess.

23. Figure 20-4 USDA dietary guidelines.23

24. Nutritional Guidelines
Alcohol
Not a nutrient
Interferes with metabolism

25. Nutritional Guidelines✓
Nutritional Guidelines
Checkpoints
20-6 What is the normal range of blood glucose?
20-7 What are typical recommendations for the relative amounts of carbohydrates, fats, and proteins in the diet?
20-8 What is the difference between saturated and unsaturated fats?
20-9 What are some adverse effects of excess alcohol consumption? 25

26. Nutritional Disorders
Learning Outcome
12. Describe some nutritional disorders.

27. Nutritional Disorders
Food Allergies
Allergens can be food or food additives.
Allergic reactions involve
Skin
Respiratory tract
Gastrointestinal tract
Reactions can be fatal.n

28. Nutritional Disorders
Malnutrition
Can occur from missing nutrients or too much of wrong foods
Protein and energy malnutrition (PEM)
Marasmus
Kwashiorkor

29. Figure 20-5 Effects of kwashiorkor.29

30. Nutritional Disorders
Overweight and Obesity
Causes are complex
Incidence is increasing
Shortens life span
Measured by body mass index (BMI)
Overweight is BMI of 25–30
Obese is BMI greater than 30
Increased risk of diabetes

31. Nutritional Disorders
Underweight
Low reserves of energy
Reproductive disturbances
Nutritional deficiencies
BMI less than 18.5

32. 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.) 32

33. Nutrition and Aging Nutritional deficiencies may develop.
Medications may interfere with appetite and absorption.

34. Body Temperature Learning Outcomes
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 some adverse effects of excessive heat and cold.

35. Body Temperature
Heat is byproduct of chemical activities in body tissues
Regulatory devices keep body temperature constant within narrow limits

36. Heat Production Amount of heat produced by organs affected by
– Exercise
– Hormone production
– Food intake
– Age

37. Heat Loss More than 80% of heat loss occurs through skin Conduction
Radiation
Convection
Evaporation
15%–20% heat loss through respiration and elimination
Heat loss prevention
Clothing
Fat layer under skin

38. 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? 38

39. Temperature Regulation
Body has internal mechanisms for regulating temperature

40. The Role of the Hypothalamus
Regulation of heat loss
Constrict skin blood vessels
Shiver
Increase cell metabolism
Overheating
Stimulate sweat glands
Dilate skin blood vessels
Muscle relaxation

41. Age Factors Newborns and elderly Reduced ability to produce heat
Reduced ability to regulate overheating

42. Normal Body Temperature
Normal range is 36.3°C to 37.6°C (97.8°F to °F)
Varies with time of day
Varies by body part

43. Fever Higher than normal body temperature Causes Infection
Malignancies
Brain injuries
Toxic reactions
Vaccine reactions
Central nervous system diseases
Crisis
Lysis

44. Responses to Excessive Heat
Heat cramps
Localized muscle cramping
Heat exhaustion
Heat retention and fluid loss
Heat stroke
Medical emergency that can be fatal

45. Responses to Excessive Cold
Hypothermia
Excessively low body temperature
Used in some types of surgery
Frostbite
Can cause permanent local tissue damage
Likely areas are face, ears, extremities

46. ✓ Body Temperature Checkpoints
20-10 What are some factors that affect heat production in the body?
20-11 What part of the brain is responsible for regulating body temperature?
20-12 What is normal body temperature?
20-13 What are some conditions brought on by excessive heat?
20-14 What is the term for excessively low body temperature? 46