Lab 4 - Metabolism

Question 1

Metabolism

Answer 1

sum total of all chemical activities in the body

Question 2

Anabolism

Answer 2

energy storage, tissue building
A = add = building

Question 3

Catabolism

Answer 3

liberation of energy, tissue or substrate breakdown

Question 4

Basal Metabolic Rate

Answer 4

• minimal energy expenditure for survival
• measured after a 14-18 hour fast
  
  • excludes body breaking down food for energy bc it is proportional to fasting time
• difficult to measure clinically

Question 5

Resting Metabolic Rate

Answer 5

• energy expenditure at rest
• measured after a 4-8 hour fast
• ALWAYS ~10% higher than BMR because also accounts for energy consumed for caloric intake

Question 6

Factors Affecting Metabolic Rate

Answer 6

(1) Sex
- males have higher BMR
- girls have higher need for body fat for survival than males
- more fat = increased metabolic rate
- lean mass consumes more energy (why males have higher BMR)

(2) Body Surface Area
- greater BSA = greater BMR
- area body encompasses = more vol. inside of body = increased energy demand and exertion = increased BMR

(3) Body Composition
- greater % fat-free mass = greater BMR
- greater % fat mass = decreased BMR
- male/female differentiation

(4) Calorie Intake
- more calories = greater BMR
- less calories = decreased BMR
- more in system, more available, more energy released, increased BMR

(5) Physical Activity
- more calories expended = greater BMR
- less calories expended = decreased BMR
- not just an EXERCISE phenomenon

(6) Sleep
- slows BMR

(7) Age
- older = decreased BMR

(8) Hormones
- some increase BMR
- thyroxine, epinephrine, growth hormone
- dysregulation can affect BMR
- Hypo- and Hyperthyroidism

(9) Genetics

(10) Body Temperature
- high body temp = increased BMR (sweating)
- low body temp = increased BMR (shivers)
- temperature affects enzymes

Question 7

Direct Calorimetry

Answer 7

measure heat production
- accuracy is better
- validity is higher

Question 8

Indirect Calorimetry

Answer 8

measure O2 consumption
- easier to do
- more cost effective

Question 9

Oxygen Consumption

Answer 9

Consumption of 1 L O2 “costs” ~5 kcals

Question 10

Absolute Oxygen Consumption

Answer 10

L/min
directly related to body size

Question 11

Relative Oxygen Consumption (VO2)

Answer 11

mL/kg/min
compare across individuals of different sizes/weights

Question 12

Energy Expenditure

Answer 12

• metabolic rate
• the consumption of macronutrients throughout the cells of the body to make energy (ATP) for survival

Question 13

Respiratory Exchange Ratio

Answer 13

RER = (VCO2 produced (1/min)) / (VO2 consumed (1/min))
- RER = 0.7 –> all fat utilized
- RER = 1.0 –> all carbs utilized

Question 14

VO2 Max

Answer 14

• measure of maximal amount of oxygen someone can consume
• accomplished by an incremental exercise test to engage the most amount of muscle fibers possible (use as much oxygen as possible)