Exam 3 Notes - Notes for Exam 3 Lecture 1- Ingestive...

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Unformatted text preview: Notes for Exam 3 Lecture 1- Ingestive Behavior Primary reinforcers Needs Survival Propagation Homeostasis Temperature regulation and other biological processes that keep body variables within fixed range Food and energy regulation 55% is basal metabolism (energy used to maintain constant body temperature) Absorptive phase o Glucose, amino acids, and fatty acids o Insulin level is high Cells metabolize glucose Liver and muscles convert glucose into glycogen o Excess nutrients are stored as fats Fasting phase o Sympathetic activity increases o Insulin level drops and glucagon level increase o Brain uses glucose o Rest of the body uses fatty acids Energy storage o Short term storage In liver and muscles as glucose and glycogen Glucose (ready energy) glycogen (energy source) requires insulin Glycogen glucose requires glucagon o Long term storage In adipose tissue as fat (energy store) Fatty acids (ready energy) Glucose regulation o Low blood glucose level is regulated by glucagon o High blood glucose level is regulated by insulin (diabetes mellitus) o Functions of insulin Storage of glucose as glycogen Transport of glucose into cells (other than brain) What starts a meal? o Social and environmental factors Conditioned consumption cue driven eating Food available in light and not available in tone (experiment) o Dietary selection Satiety for a specific food that has been ingested recently in the absence of general satiety for all foods. o Physiological hunger signals Glucoprivation- decreased availability of glucose to cells (detected by brain and liver) Lipoprivation- decreased availability of fatty acids to cells (detected by liver) What stops a meal? o Gastrointestinal factors Cholecystokinin (CCK) satiety peptide hormone Causes gallbladder to contract Secreted by duodenum Does not cross BBB Provides a satiety signal to the brain via vagus nerve o Long-term satiety Signals from fat tissue Fat cells secrete leptin (hormone) into blood circulation Leptin inhibits eating Leptin inhibits arcuate neurons that release NPY and excites alpha- MSH (a melanocortin) NPY activates NPY receptors which increases eating Alpha-MSH activates MRC which inhibits eating Leptin reaches hypothalamus This inhibits hunger peptides (neuropeptides Y) and excites satiety peptides (melanocortins) Neural mechanisms o Nucleus of solitary tract and area postrema (NST/AP) Receives taste information Sensory information from internal organs via vagus nerve Contains detectors for glucose Vital for glucoprivic and lipoprivic feeding Fluid regulation Osmotic thirst-a thirst resulting from eating salty foods o Osmoreceptors Stomach and duodenum OVLT (organum vasculosum laminae terminalis) third ventricle Hypovolemic thirst-a thirst resulting from loss of fluids due to bleeding or...
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This note was uploaded on 11/11/2010 for the course PSY 308 taught by Professor Jones during the Spring '08 term at University of Texas at Austin.

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Exam 3 Notes - Notes for Exam 3 Lecture 1- Ingestive...

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