Chapter 21 - Endocrine

Chapter 21 - Endocrine - Chapter 7: Endocrine - Regulation...

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Anabolism: Molecules used in generating energy are also used in the synthesis of large molecules depending on what the body needs Mechanisms exist to regulate pathways II. Energy Intake, Utilization, and Storage Following intake, nutrients can be catabolized for energy, used as substrates for new molecules or stored for energy as glycogen (in the muscles and liver) or fat Basal Metabolic Rate (BMR): Rate of energy expenditure of a person awake, resting, lying down & fasted for 12 hours, represents min energy expenditure necessary to maintain body functions BMR increases with increase in activity Measures oxygen consumption and carbon dioxide output A rapid BMR creates high CO 2 levels in the atmosphere surrounding the person A low BMR means the body is conserving energy for a time when it is needed, the older you are the more the body attempts to conserve energy Body wants to maintain a set BMR III. Energy Balance: To maintain energy balance the energy input must equal the energy output Energy input includes work performed and the heat released from the work A positive balance means that the energy intake > energy output and energy in excess of output gets stored A negative balance means that the energy intake < energy output, need to obtain energy from stored resources, during negative balance you lose weight IV. Energy Balance Varies During Absorptive and Postabsorptive States: Energy balance is not continuous because energy input is intermittent (we do not eat continuously) The Absorptive state is 3-4 hours following the consumption of a meal when nutrient levels in the bloodstream are high The Postabsorptive state occurs between meals when stored energy must be mobilized Absorptive State: Energy input > output as nutrients absorbed Glucose = primary energy source for the cell Excess nutrients taken up will be stored in the liver and muscles as glycogen, and in adipose tissue as triglycerides Postabsorptive State: Energy input < output Glucose is spared for use by the brain and other sources for energy are used Stored nutrients are broken down and mobilized
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Cells Must Have Constant Energy Supply: During the absorptive state energy is stored in macromolecules During the postabsorptive state stored energy is mobilized Metabolic Reactions of the Absorptive State: (Fig 7.3)
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This note was uploaded on 09/22/2009 for the course BIOL 2160 taught by Professor Kt during the Spring '08 term at LSU.

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Chapter 21 - Endocrine - Chapter 7: Endocrine - Regulation...

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