CH. 17 Energy Balance and Temperature Regulation

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CH. 17Energy Balance and Temperature Regulation
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Do We Have Enough Energy?

• Understand what energy is and what it is used for
• Know how much energy is actually used and how
  much we lose as heat
• Understand what metabolic rate and basal
  metabolic rate are a measure of
• Know the types of energy balances that exsist
• Understand what nutrients are and how we regulate
  nutrient intake

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Energy

• Input energy stored in the bonds of ingested
  food
• Output the use of that energy
• External work
• Energy expended during skeletal voluntary
  skeletal muscle contractions
• Internal work
• All forms of biological expenditure that do not
  perform work outside of the body
• Involuntary skeletal muscle contractions
• All life sustaining activities that are always
  occurring

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Energy Consumption

• How much energy do we actually use?
• Lose about 75 as heat
• Metabolic rate
• Rate of energy use
• Energy used/unit time
• Expressed in calories, and kilocalories
  (Calories)
• BMR Basal metabolic rate
• Minimum waking rate of internal energy
  expenditure
• Influenced by thyroid hormone

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Neutral Energy Balance

• Energy input energy output
• Three states of energy balance
• Neutral energy balance
• Amount of intake to output
• Body weight remains constant
• Positive energy balance
• Amount of intake gt output
• Excess stored s adipose, weight increases
• Negative energy balance
• Amount of intake lt output
• Body must use stored energy, weight decreases

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Nutritious and Delicious

• Nutrient
• An ingested chemical that is used for growth,
  repair, and maintenance of the body
• Two categories
• Macronutrients
• Must consume in large quantities
• Water, carbohydrates, lipids , and proteins
• Micronutrients
• Small quantities needed
• Minerals and vitamins
• Calories
• Kcal
• Measure of the capacity to do work

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Metabolic States

• Absorptive state
• Nutrients are being absorbed and my be used
  immediately to meet needs
• Postabsorptive state
• Stomach and small intestines empty, energy needs
  met from stored fuel

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Regulation of Appetite

• Short-term regulators
• Ghrelin produces sensation of hunger
• Peptide YY (PYY) sensation of satisfaction
• CCK sensory stimulus of vagus nerve
  (suppressor)
• Long-term regulators (adiposity signals)
• Leptin
• Insulin
• Arcuate nucleus of hypothalamus
• NPY - stimulator
• Melanocortin - suppressor

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Psychosocial and Environmental Influences

• Eat out of habit
• Social custom
• Familial customs

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