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

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

FACTORS INFLUENCING METABOLIC RATE zEXERCISE zFOOD INTAKE zSHIVERING zANXIETY

BASAL METABOLIC RATE zBODY’S “IDLING SPEED” (THE MINIMAL WAKING RATE OF INTERNAL ENERGY EXPENDITURE) zDIRECT CALORIMETERY(MEASURE RATE OF HEAT PRODUCTION) zINDIRECT CALORIMETERY (MEASURE OXYGEN CONSUMPTION) z(SEE LAB NOTES FROM DEC.2)

FACTORS WHICH INFLUENCE BMR zFOOD INTAKE zTHYROID HOMONE zEVEN LOWER LEVELS DURING SLEEP (10-15%)

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

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

STORAGE AND/OR DEPLETION zNEUTRAL ENERGY BALANCE OCCURS WHEN INPUT AND OUTPUT MATCH zPOSITIVE ENERGY BALANCE OCCURS WHEN INTAKE EXCEEDS OUTPUT - ENERGY IS STORED AS GLYCOGEN OR FAT zNEGATIVE ENERGY BALANCE OCCURS WHEN OUTPUT EXCEEDS INTAKE- ENERGY STORES ARE DEPLETED

FOOD AS FUEL zCARBOHYDRATE 4 CAL/G zPROTEIN 4 CAL/G zFAT 9 CAL/GRAM zETHANOL 7 CAL/G

FOOD AS STORED FUEL z3500 CALORIES = 1 LB OF BODY MASS

EFFICIENCY OF METABOLISM z50% GOES TO ATP z50% GOES TO HEAT

FOOD INTAKE zCONTROLED BY HYPOTHALAMUS zFEEDING CENTERS zSATIETY CENTERS

CONTROL OF FUEL METABOLISM zGLYCOGENESIS zGLYCOGENOLYSIS zGLUCONEOGENESIS zPROTEIN SYNTHESIS zPROTEIN DEGRADATION zFAT SYNTHESIS zFAT BREAKDOWN

ANABOLISM VS CATABOLISM zBUILD UP VS BREAKDOWN OF LARGE MOLECULES zANABOLISM REQUIRES ENERGY (ATP) zCATABOLISM:ENERGY PRODUCTION

BLOOD GLUCOSE zONE GRAM YIELDS ABOUT 4 CALORIES z70 KG PERSON 2,000 CALORIES/DAY zNEED 500G GLUCOSE zAS AN ISOTONIC SOLUTION THAT WOULD BE ABOUT 10L zTHE ACTUAL AMOUNT IS ABOUT 20G OR ENOUGH FOR 1 HOUR

PANCREATIC HORMONES AND BLOOD GLUCOSE zINSULIN zGLUCAGON

INSULIN: ACTION ON BLOOD SUGAR zBETA CELLS IN ISLETS OF LANGERHANS: INSULIN zFACILITIES GLUCOSE ENTRY INTO CELLS zSTIMULATES GLYCOGENESIS zINHIBITS GLYCOGENOLYSIS zINHIBITS GLUCONEOGENESIS

INSULIN: ACTION ON FAT zINCREASES TRANSPORT INTO ADIPOSE CELLS zPROMTES TRIGLYCERIDE SYNTHESIS zINHIBITS LIPOLYSIS

INSULIN: ACTION ON PROTEIN zPROMOTES UPTAKE OF AA BY MUSCLE AND OTHER TISSUE zPROMOTES PROTEIN SYNTHESIS zINHIBITS PROTEIN DEGRADATION

CONTROL OF INSULIN SECRETION zNEGATIVE FEEDBACK: BLOOD SUGAR zBLOOD AA zGI HORMONES zPARASYMPATHETIC ACTIVITY

TWO TYPES OF DIABETES MELLITUS zTYPE I: AUTOIMMUNE DESTRUCTION OF BETA CELLS, LACK OF INSULIN SECRETION zTYPE II: REDUCED SENSITIVITY OF INSULIN RECEPTORS

ACUTE EFFECTS OF DIABETES MELLITUS zEXTRACELLULAR GLUCOSE EXCESS zGLUCOSE IN URINE zEXCESS FLUID LOSS zCIRCULATORY FAILURE zRENAL FAILURE zNERVOUS SYSTEM MALFUNCTION DUE TO DEHYDRATION zEXCESSIVE FOOD INTAKE zPROGRESSIVE WEIGHT LOSS zMOBILIZTION OF FAT zKETOSIS zACIDOSIS zCOMA AND DEATH

GLUCAGON zPANCREATIC ALPHA CELLS zGENERALLY OPPOSES ACTIONS OF INSULIN zDECREASE GLYCOGEN SYNTHESIS zPROMOTE GLYCOGENOLYSIS zSTIMULATE GLUCONEOGENESIS zPROMOTES FAT BREAKDOWN zONLY IN LIVER: PROTEIN CATABOLISM

EPINEPHRINE, CORTISOL, AND GROWTH HORMONE zALL INCREASE BLOOD GLUCOSE AND FATTY ACIDS zCORTISOL INCREASES BLOOD AA AND DECREASES MUSCLE PROTEIN zGH DECREASES BLOOD AA AND INCREASES MUSCLE PROTEIN

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