UNIT 6: CHAPTER 25
NUTRITION, METABOLISM AND TEMPERATURE REGULATION
Define Basal Metabolic Rate (BMR) and describe 3 major uses of metabolic energy in the
body. Pg 955
o Metabolic rate is the total amount of energy produced and used by the body per
unit of time.
o A unit of ATP is produced in cells at about the same rate as it is used up.
o The Basal Metabolic Rate (BMR) is the energy needed to keep the resting body
functional.
o BMR is determined by measuring the oxygen consumption of a person who is awake
and restful and has not eaten for 12 hours. The liters of oxygen consumed are then
multiplied by 4.825 (because each liter of oxygen we use results in 4.825kcal of
energy being used).
o In the average person, basal metabolism accounts for about 60% of energy
expenditure.
o Basal metabolism supports active transport mechanisms, muscle tone, maintenance
of body temperature, beating of the heart and other activities.
o A number of factors can affect BMR. For example: Muscle tissue is metabolically
more active than adipose tissue, even at rest. Therefore, people with well-developed
muscles have a higher BMR than other people.
o Younger people also have a higher BMR than older people because of increases cell
activity, especially during growth phases.
o Metabolic energy in the body is used in 3 ways: (1) for BMR, (2) for the thermic
effect of food and (3) for muscular activity.
o BMR is discussed above.
o The thermic effect of food: This refers to energy involved in the digestion and
absorption of food.
o When we ingest food, our digestive organs and intestinal linings produce secretions,
the motility of our digestive tract increases, active transport increases and our liver is
involved in synthesizing new molecules. All of these events require energy and this is
referred to as the thermic effect of food. This accounts for about 10% of our body’s
energy expenditure.
o Muscular activity consumes about 30% of the body’s energy. Any physical activity
resulting from skeletal muscle movement requires the expenditure of energy, in
addition, the heart and muscle of respiration also require energy.
o The number of kilocalories expended in an activity depends on the amount and
duration of muscular work.
NUTRITION, METABOLISM AND TEMPERATURE REGULATION
Define Basal Metabolic Rate (BMR) and describe 3 major uses of metabolic energy in the
body. Pg 955
o Metabolic rate is the total amount of energy produced and used by the body per
unit of time.
o A unit of ATP is produced in cells at about the same rate as it is used up.
o The Basal Metabolic Rate (BMR) is the energy needed to keep the resting body
functional.
o BMR is determined by measuring the oxygen consumption of a person who is awake
and restful and has not eaten for 12 hours. The liters of oxygen consumed are then
multiplied by 4.825 (because each liter of oxygen we use results in 4.825kcal of
energy being used).
o In the average person, basal metabolism accounts for about 60% of energy
expenditure.
o Basal metabolism supports active transport mechanisms, muscle tone, maintenance
of body temperature, beating of the heart and other activities.
o A number of factors can affect BMR. For example: Muscle tissue is metabolically
more active than adipose tissue, even at rest. Therefore, people with well-developed
muscles have a higher BMR than other people.
o Younger people also have a higher BMR than older people because of increases cell
activity, especially during growth phases.
o Metabolic energy in the body is used in 3 ways: (1) for BMR, (2) for the thermic
effect of food and (3) for muscular activity.
o BMR is discussed above.
o The thermic effect of food: This refers to energy involved in the digestion and
absorption of food.
o When we ingest food, our digestive organs and intestinal linings produce secretions,
the motility of our digestive tract increases, active transport increases and our liver is
involved in synthesizing new molecules. All of these events require energy and this is
referred to as the thermic effect of food. This accounts for about 10% of our body’s
energy expenditure.
o Muscular activity consumes about 30% of the body’s energy. Any physical activity
resulting from skeletal muscle movement requires the expenditure of energy, in
addition, the heart and muscle of respiration also require energy.
o The number of kilocalories expended in an activity depends on the amount and
duration of muscular work.
