THE%20BASAL%20METABOLIC%20RATE

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THE BASAL METABOLIC RATE

• D. C. MIKULECKY
• PROFESSOR OF PHYSIOLOGY
• VIRGINIA COMMONWEALTH UNIVERSITY

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

• EXERCISE
• FOOD INTAKE
• SHIVERING
• ANXIETY

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BASAL METABOLIC RATE

• BODYS 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)

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FACTORS WHICH INFLUENCE BMR

• FOOD INTAKE
• THYROID HOMONE
• EVEN LOWER LEVELS DURING SLEEP (10-15)

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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

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ENERGY BALANCE WITH RESPECT TO THE BODY
INPUT - OUTPUT STORAGE OR DEPLETION (CONTINUI
TY EQUATION ?E/?t ?2E)
(
)
OUTPUT INTERNAL WORK EXTERNAL WORK
INTERNAL WORK ------gt HEAT
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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

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FOOD AS FUEL

• CARBOHYDRATE 4 CAL/G
• PROTEIN 4 CAL/G
• FAT 9 CAL/GRAM
• ETHANOL 7 CAL/G

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FOOD AS STORED FUEL

• 3500 CALORIES 1 LB OF BODY MASS

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EFFICIENCY OF METABOLISM

• 50 GOES TO ATP
• 50 GOES TO HEAT

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FOOD INTAKE

• CONTROLED BY HYPOTHALAMUS
• FEEDING CENTERS
• SATIETY CENTERS

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CONTROL OF FUEL METABOLISM

• GLYCOGENESIS
• GLYCOGENOLYSIS
• GLUCONEOGENESIS
• PROTEIN SYNTHESIS
• PROTEIN DEGRADATION
• FAT SYNTHESIS
• FAT BREAKDOWN

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ANABOLISM VS CATABOLISM

• BUILD UP VS BREAKDOWN OF LARGE MOLECULES
• ANABOLISM REQUIRES ENERGY (ATP)
• CATABOLISMENERGY PRODUCTION

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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

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PANCREATIC HORMONES AND BLOOD GLUCOSE

• INSULIN
• GLUCAGON

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INSULIN ACTION ON BLOOD SUGAR

• BETA CELLS IN ISLETS OF LANGERHANS INSULIN
• FACILITIES GLUCOSE ENTRY INTO CELLS
• STIMULATES GLYCOGENESIS
• INHIBITS GLYCOGENOLYSIS
• INHIBITS GLUCONEOGENESIS

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INSULIN ACTION ON FAT

• INCREASES TRANSPORT INTO ADIPOSE CELLS
• PROMTES TRIGLYCERIDE SYNTHESIS
• INHIBITS LIPOLYSIS

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INSULIN ACTION ON PROTEIN

• PROMOTES UPTAKE OF AA BY MUSCLE AND OTHER TISSUE
• PROMOTES PROTEIN SYNTHESIS
• INHIBITS PROTEIN DEGRADATION

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CONTROL OF INSULIN SECRETION

• NEGATIVE FEEDBACK BLOOD SUGAR
• BLOOD AA
• GI HORMONES
• PARASYMPATHETIC ACTIVITY

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TWO TYPES OF DIABETES MELLITUS

• TYPE I AUTOIMMUNE DESTRUCTION OF BETA CELLS,
  LACK OF INSULIN SECRETION
• TYPE II REDUCED SENSITIVITY OF INSULIN RECEPTORS

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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

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GLUCAGON

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

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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

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