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23 Cards in this Set
- Front
- Back
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Digestion
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-the gastrointestinal process of breaking down food and absorbing its constituents into the body
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How is energy delivered?
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1)lipids
2)amino acids 3)glucose |
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How is energy stored?
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1)fat
2)protein 3)glycogen |
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Phases of Energy Metabolism
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1)cephalic phase
2)absorptive phase 3)fasting phase |
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Cephalic Phase
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“preparatory phase”
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absorptive phase
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“energy is absorbed into the bloodstream”; meets immediate energy needs
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fasting phase
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all the unstored energy as been used
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Pancreatic Hormones
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1)insulin
2)glucagon |
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Insulin
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promotes use of glucose as primary source of energy
-promotes conversion of blood-borne fuels to storable forms -promotes storage of glycogen in liver and muscle, fat in adipose tissue, protein in muscle -in cephalic phase, insulin lowers level of blood-borne fuels, and in absorptive phase it minimizes increasing levels of fuels by utilizing and storing them |
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Gluconeogenesis
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conversion of protein to glucose
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“glucostatic theory”
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glucose levels determine what we eat
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“lipostatic theory”
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fat stores determine the amount of consumption over long term
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Problems with the Set Point theory
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epidemic of obesity and overweight people should not occur
-inconsistent with basic eating-related evolutionary pressure -fail to recognize major influences such as sight, smell and taste |
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Positive-Incentive Perspective
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we are drawn by the pleasure of eating, evolved to crave food
-eating is influenced by many factors: 1-learned preference for flavors 2-past experiences 3-time since the last meal 4-social influences |
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Factors that determine what/when/how much we eat
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-Adaptive species-typical preferences
-sweet and fatty tastes: high energy, vitamins and minerals -salty: sodium-rich |
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“appetizer effect”
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small amounts of food may increase hunger
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“satiety”
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feeling full; food in gut and glucose in blood can induce satiety signals
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Known as "feeding center"
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- LH lesioned animals starve to death, LH became known as the “feeding center”
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known as the "satiety center"
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-VMH lesioned animals became fat, grew to be 4x their bod weight, VMH became known as the “satiety center”
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lipogenesis
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production of fat
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lipolysis
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breakdown of fat
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Role of G.I Tract in Satiety
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studies suggest that stomach contractions lead to hunger (Cannon and Washburn) but someone who had their stomach removed still reported hunger pangs
-Koopmans used second stomach preparation; rats eat less when 2nd stomach was loaded with food even though no innervation or nutrients absorbed |
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Hunger and Satiety Peptides
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gut peptides that decrease meal size: cholecystokinin (CCK), bombesin, glucagon, alpha-melanocyte-stimulating hormone, somatostatin
- peptides are usually synthesized in the hypothalamus: neuropeptide Y, galanin, orexin-A and ghrelin -hypothalamus plays role in eating behaviours |
