THE BASAL METABOLIC RATE

1. THE BASAL METABOLIC RATE D. C. MIKULECKY PROFESSOR OF PHYSIOLOGY VIRGINIA COMMONWEALTH UNIVERSITY

2. THE METABOLIC RATE METABOLIC RATE = ENERGY EXPENDITURE PER UNIT TIME (Calories/hour)

3. FACTORS INFLUENCING METABOLIC RATE • EXERCISE • FOOD INTAKE • SHIVERING • ANXIETY

4. BASAL METABOLIC RATE • BODY’S “IDLING SPEED” (THE MINIMAL WAKING RATE OF INTERNAL ENERGY EXPENDITURE) • DIRECT CALORIMETERY(MEASURE RATE OF HEAT PRODUCTION) • INDIRECT CALORIMETERY (MEASURE OXYGEN CONSUMPTION) • (SEE LAB NOTES FROM DEC.2)

5. FACTORS WHICH INFLUENCE BMR • FOOD INTAKE • THYROID HOMONE • EVEN LOWER LEVELS DURING SLEEP (10-15%)

6. ENERGY • THE CAPACITY TO DO WORK • THE CALORIE IS THE AMMOUNT OF HEAT ENERGY NECESSARY TO RAISE THE TEMPERATURE OF 1 GRAM OF WATER 1 DEGREE CENTIGRADE • THE NUTRITIONAL CALORIE IS 1000 CALORIES OR THE KILOCALORIE

7. ENERGY BALANCE WITH RESPECT TO THE BODY INPUT - OUTPUT = STORAGE OR DEPLETION (CONTINUITY EQUATION E/t = 2E) ( ) OUTPUT = INTERNAL WORK + EXTERNAL WORK INTERNAL WORK ------> HEAT

8. STORAGE AND/OR DEPLETION • NEUTRAL ENERGY BALANCE OCCURS WHEN INPUT AND OUTPUT MATCH • POSITIVE ENERGY BALANCE OCCURS WHEN INTAKE EXCEEDS OUTPUT - ENERGY IS STORED AS GLYCOGEN OR FAT • NEGATIVE ENERGY BALANCE OCCURS WHEN OUTPUT EXCEEDS INTAKE- ENERGY STORES ARE DEPLETED

9. FOOD AS FUEL • CARBOHYDRATE 4 CAL/G • PROTEIN 4 CAL/G • FAT 9 CAL/GRAM • ETHANOL 7 CAL/G

10. FOOD AS STORED FUEL • 3500 CALORIES = 1 LB OF BODY MASS

11. EFFICIENCY OF METABOLISM • 50% GOES TO ATP • 50% GOES TO HEAT

12. FOOD INTAKE • CONTROLED BY HYPOTHALAMUS • FEEDING CENTERS • SATIETY CENTERS

13. CONTROL OF FUEL METABOLISM • GLYCOGENESIS • GLYCOGENOLYSIS • GLUCONEOGENESIS • PROTEIN SYNTHESIS • PROTEIN DEGRADATION • FAT SYNTHESIS • FAT BREAKDOWN

14. ANABOLISM VS CATABOLISM • BUILD UP VS BREAKDOWN OF LARGE MOLECULES • ANABOLISM REQUIRES ENERGY (ATP) • CATABOLISM:ENERGY PRODUCTION

15. BLOOD GLUCOSE • ONE GRAM YIELDS ABOUT 4 CALORIES • 70 KG PERSON 2,000 CALORIES/DAY • NEED 500G GLUCOSE • AS AN ISOTONIC SOLUTION THAT WOULD BE ABOUT 10L • THE ACTUAL AMOUNT IS ABOUT 20G OR ENOUGH FOR 1 HOUR

16. PANCREATIC HORMONES AND BLOOD GLUCOSE • INSULIN • GLUCAGON

17. INSULIN: ACTION ON BLOOD SUGAR • BETA CELLS IN ISLETS OF LANGERHANS: INSULIN • FACILITIES GLUCOSE ENTRY INTO CELLS • STIMULATES GLYCOGENESIS • INHIBITS GLYCOGENOLYSIS • INHIBITS GLUCONEOGENESIS

18. INSULIN: ACTION ON FAT • INCREASES TRANSPORT INTO ADIPOSE CELLS • PROMTES TRIGLYCERIDE SYNTHESIS • INHIBITS LIPOLYSIS

19. INSULIN: ACTION ON PROTEIN • PROMOTES UPTAKE OF AA BY MUSCLE AND OTHER TISSUE • PROMOTES PROTEIN SYNTHESIS • INHIBITS PROTEIN DEGRADATION

20. CONTROL OF INSULIN SECRETION • NEGATIVE FEEDBACK: BLOOD SUGAR • BLOOD AA • GI HORMONES • PARASYMPATHETIC ACTIVITY

21. TWO TYPES OF DIABETES MELLITUS • TYPE I: AUTOIMMUNE DESTRUCTION OF BETA CELLS, LACK OF INSULIN SECRETION • TYPE II: REDUCED SENSITIVITY OF INSULIN RECEPTORS

22. ACUTE EFFECTS OF DIABETES MELLITUS • EXTRACELLULAR GLUCOSE EXCESS • GLUCOSE IN URINE • EXCESS FLUID LOSS • CIRCULATORY FAILURE • RENAL FAILURE • NERVOUS SYSTEM MALFUNCTION DUE TO DEHYDRATION • EXCESSIVE FOOD INTAKE • PROGRESSIVE WEIGHT LOSS • MOBILIZTION OF FAT • KETOSIS • ACIDOSIS • COMA AND DEATH

23. GLUCAGON • PANCREATIC ALPHA CELLS • GENERALLY OPPOSES ACTIONS OF INSULIN • DECREASE GLYCOGEN SYNTHESIS • PROMOTE GLYCOGENOLYSIS • STIMULATE GLUCONEOGENESIS • PROMOTES FAT BREAKDOWN • ONLY IN LIVER: PROTEIN CATABOLISM

24. EPINEPHRINE, CORTISOL, AND GROWTH HORMONE • ALL INCREASE BLOOD GLUCOSE AND FATTY ACIDS • CORTISOL INCREASES BLOOD AA AND DECREASES MUSCLE PROTEIN • GH DECREASES BLOOD AA AND INCREASES MUSCLE PROTEIN

25. OVERALL REGULATION OF BLOOD GLUCOSE (+) RELEASE FROM LIVER EPINEPHRINE AND NOREPINEPHRIN (+) (-) (+) GLUCAGON BLOOD GLUCOSE INSULIN GLUCOCORTICOIDS (-) (+) (-) GH CONSUMPTION BY MUSCLE AND FAT CELLS