Vander et al

Vander et al.: Human Physiology: The Mechanism of Body The GrawHill

Companies, 2001Chapter18

Regulation of Organic Metabolism,

Growth, and Energy BalanceSECTION A

CONTROL AND INTEGRATION OF CARBOHYDRATE, PROTEIN, AND FAT METABOLISM

Events of the Absorptive and Postabsorptive States

Absorptive State

Postabsorptive State

Endocrine and Neural Control of the Absorptive and Postabsorptive States

Insulin

Glucagon

Epinephrine and Sympathetic Nerves

to Liver and Adipose Tissue

Other Hormones

Summary of Hormonal Controls

Fuel Homeostasis in Exercise and Stress

Diabetes Mellitus

Hypoglycemia as a Cause of Symptoms

Regulation of Plasma CholesterolSECTION A SUMMARY

SECTION A KEY TERMS

SECTION A REVIEW QUESTIONSSECTION BCONTROL OF GROWTH

Bone Growth

Environmental Factors

Influencing Growth

Hormonal Influences on Growth

Growth Hormone and Insulin-Like

Growth Factors

Thyroid Hormones

Insulin

Sex Hormones

Cortisol

Compensatory GrowthSECTION B SUMMARY

SECTION B KEY TERMS

SECTION B REVIEW QUESTIONS

SECTION CREGULATION OF TOTAL-BODY ENERGY BALANCE AND TEMPERATURE

Basic Concepts of Energy Expenditure

Metabolic Rate

Regulation of Total-Body Energy Stores

Control of Food Intake

Overweight and Obesity

Eating Disorders: Anorexia Nervosa

and Bulimia

What Should We Eat?

Regulation of Body Temperature

Mechanisms of Heat Loss or Gain

Temperature-Regulating Reflexes

Temperature Acclimatization

Fever and HyperthermiaSECTION C SUMMARY

SECTION C KEY TERMS

SECTION C REVIEW QUESTIONS

CHAPTER 18 CLINICAL TERMS

CHAPTER 18 THOUGHT QUESTIONSSECTION A

CONTROL AND INTEGRATION OF CARBOHYDRATE, PROTEIN, AND FAT METABOLISM

Events of the Absorptive and Postabsorptive States

Mechanisms have evolved for survival during alternating

periods of plenty and fasting. We speak of two

functional states or periods: the absorptive state, during

which ingested nutrients are entering the blood

from the gastrointestinal tract, and the postabsorptive

state, during which the gastrointestinal tract is empty

of nutrients and energy must be supplied by the bodys

own stores. Since an average meal requires approximately

4 h for complete absorption, our usual threemeal-

a-day pattern places us in the postabsorptive

state during the late morning and afternoon and almost

the entire night. We shall refer to going more than

24 h without eating as fasting.

During the absorptive period, some of the ingested

nutrients supply the energy needs of the body, and the

remainder are added to the bodys energy stores, to be

called upon during the next postabsorptive period.

Total-body energy stores are adequate for the average

person to easily withstand a fast of many weeks (provided

that water is available).

Figures 181 and 182 summarize the major pathways

to be described in this chapter. Although they

may appear formidable at first glance, they should

present little difficulty after we have described the

component parts, and these figures should be referred

to constantly during the following discussion.

Absorptive State

We shall assume, for this discussion, that an average

meal contains all three of the major nutrients

carbohydrate, protein, and fatwith carbohydrate

constituting most of the meals energy content (calories).

Recall from Chapter 17 that carbohydrate and