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Unformatted text preview: egulated by our metabolism (body’s rate of (body’s energy utilization) and other physiological mechanisms (e.g. satiety); ► keep body in energy keep homeostasis homeostasis – Set point: biologically determined standard around biologically which body weight (fat mass) is regulated ► overeat or under-eat BUT BUT over time we may settle at new weight “Biology does not determine fixed body weight, Biology but but rather a range or zone of body weight” 6 Create PDF files without this message by purchasing novaPDF printer ( 11/30/2009 The Physiology of Hunger Signals that Start & Terminate a Meal Muscle contractions? (balloon experiment) Enzymes Enzymes break down food into key nutrients (e.g. Glucose: a major source of immediately reusable fuel); Changes in glucose supply (↓) signal hunger hunger Other Other satiety signals: - Stomach & intestinal walls stretch Stomach - Chemical signals like Cholecystokinin (CCK) (peptide –type of Cholecystokinin type hormone released by small intestine) & others travel from bloodstream to brain producing satiety Weight Weight Regulation Signals that Regulate General Appetite & Weight – Leptin (a hormone secreted by fat cells) reaches (a brain: brain: ↓appetite & ↑ energy expenditure (long-term term effects;↑ effects;↑ potency of other signals) – Ob gene directs fat cells to produce leptin Mutation obesity Daily injections reduce appetite in mice – Db gene mutation p...
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This document was uploaded on 01/15/2014.

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