1. Unit Thirteen: Metabolism and Temperature Regulation
Chapter 72: Energetics and Metabolic Rate
Guyton and Hall, Textbook of Medical Physiology, 12th edition

2. Basic Properties
ATP Functions as the “Energy Currency” in Metabolism
ATP is generated by combustion of cbhs
ATP energizes the synthesis of cellular components
ATP energizes muscle contraction
ATP energizes active transport across membranes
ATP energizes glandular secretion
ATP energizes nerve conduction

3. Basic Properties
Phosphocreatinine Functions as an Accessory Storage
Depot for Energy and as an “ATP Buffer”

4. Basic Properties
Anaerobic Versus Aerobic Energy
Cbhs are the only significant food that can be used to
generate energy without oxygen
The best source of energy under anaerobic conditions
is the stored glycogen of cells
Energy utilization during strenuous bursts of activity
is derived mainly from glycolysis
Extra consumption of oxygen repays the “oxygen debt”
after completion of strenuous exercise

5. Control of Energy Release
Rate Control of Enzyme Catalyzed Reactions
(the Michaelis-Menten Equation)

6. Control of Energy Release
Role of Enzyme and Substrate Concentrations
in Regulation of Metabolic Reactions
Fig Effect of substrate and enzyme concentrations on the rate
of enzyme-catalyzed reactions

7. Control of Energy Release
Rate Limitations in a Series of Reactions
Overall rate is determined by the rate of the
slowest step in the series (rate-limiting step)
ADP concentration is a rate controlling factor
in energy release; under resting conditions, the
concentration of ADP in a cell is slight

8. Control of Energy Release
Metabolic Rate
Metabolism means all the chemical reactions in all
the cells of the body; metabolic rate is expressed
in terms of the rate of heat liberation during
chemical reactions
Heat is the end product of almost all the energy
released in the body
Measurement is usually through direct or indirect
calorimetry

9. Control of Energy Release
Energy Metabolism-Factors That Influence Energy
Output
Basal Metabolic Rate (BMR)-minimum energy
expenditure for the body to exist
Fig Components of energy
expenditure

10. Fig. 72.4 Normal basal metabolic rates at different ages for each sex

11. Control of Energy Release
Thyroid hormone increases metabolic rate
Male sex hormone increases metabolic rate
Growth hormone increases metabolic rate
Fever increases metabolic rate
Sleep decreases metabolic rate
Malnutrition decreases metabolic rae

12. Control of Energy Release
Energy Used for Processing Food
Thermogenic effect of food
Energy used for nonshivering thermogenesis