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24 Cards in this Set
- Front
- Back
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Satiety
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the feeling of being full
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leptin
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-secreted by adipocytes (fat cells)
-a hormone -essential for normal body weight regulation -amount of leptin in blood indicates the total amount of triglyceride fat stored in adipose tissue *the larger the fat stores, the more leptin released into the blood |
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arcuate nucleus
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-in the hypothalamus
-major site for leptin action |
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melanofortins
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-group of hormones
-important in varying the skin color for the purpose of camouflage in some species -exert an unexpected role in energy homeostasis -inhibit hypothalamus to decrease food intake -no role in skin color in humans |
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lateral hypothalamic area (LHA)
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-richly supplies by axons from the NPY- and melanocortin-secreting neurons of the arcuate nucleus
-release chemical messengers in reponse to input from the arcuate nucleus neurons -site of the classical appetite center -produces orexins (neuropeptides)which stimulate food intake |
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paraventricular nucleus (PVN)
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-similar to LHA
-released chemical messengers in reponse to input from the arcuate nucleus neurons -decrease appetite and food intake |
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hypothalamus
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-maintain energy balance and long-term control of body weight
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internal core temperature
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-remains fairly constant
-subject to precise regulation to maintin its homeostatic constancy -core tissues do best with a temp around 100 degrees F |
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radiation
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-the emission of heat energy from the surface of a warm body in the form of electromagnetic waves/heat waves
-when it strikes an object and is absorbed, the energy of the wave motion is transformed into heat within the object -human body both emits and absorbs radiant energy -warmer to cooler |
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conduction
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-transfer of heat between objects of differing temps that are in direct contact with each other
-heat moves down thermal gradient -warmer to cooler by transfer from molecule to molecule -movement (fast=warm, slow=cold) -depends on temp difference between touching objects and the thermal conductivity of the substances involved |
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convection
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-transfer of heat energy by air currents (or water)
-as body loses heat by conduction to surround air, the air is warmed -warm air is light; it rises while cooler air moves next to skin to replace the vacating warm air -convection currents carry heat away from the body |
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evaporation
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-the final method fo heat trasnfer used by the body
-water evaporates from the skin surface, the heat needed to transform water to a gaseous state is absorbed from skin= cooling the body -heat loss occurs continually from the linings of the respiratory airways and from the surface of the skin -heat continuously lost through the water vapor in the expired air as a result of the air's humidification during tis passage through the respiratory sys -skin not waterproof=water molecules constantly diffuse through the skin and evaporate (not sweating!) |
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fever production
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Infection/Inflammation> Neutrophils (release)> Endogenous pyrogen> Prostaglandins> raise Hypothalamic set point> Initiation of "cold response"> raise Heat Production; lower Heat Loss> raise Body temp to new set point= FEVER
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nicotinamide adenine dinucleotide (NAD) & flavine adenine dinucleotide (FAD)
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-converted by the transper of hydrogen to NADH and FADH2
-hydrogen carriers |
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electron transport chain
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-NADH and FADH2 enter
-chain consistes of e- carrier molecules located in the inner mitochondrial mem lining the cristae -high-energy e- are extracted from the H held in the NADH and FADH2 -e- transfered from one e- carrier molecule to another, within cristae mem -NADH and FADH2= NAD and FAD * can now pick up more H *link between citric acid cycle and e- transport chain - e- high energy levels to low (release energy) - e- then passed to O2 * e- bound to oxygen are in their lowest energy state - oxygen breathed in enters mitochondria to serve as final e- acceptor - negative oxygen combines w/ postively charged H to form water |
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oxidative phosphorylation
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- oxygen used in final steps of energy conversion when a phosphate is added to form ATP
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anaerobic
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-lack of oxygen
-the degredation of glucose cannot proceed beyond glycolysis |
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glycolysis
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-in the cytosol
-breakdown of glucose into pyruvic acid -produces a low yield of two molecules of ATP per molecule of glucose -untapped energy in glucose molecules remains locked in the bonds of pyruvic acid * are eventually converted to lactic acid if they don't enter the pathway that ultimately leads to oxidative phosphorylation |
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aerobic
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-oxygen present-mitochondrial processing harnesses sufficient energy to generate 34 more molecules of ATP
-total 36 ATPs per molecule of glucose |
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glucose
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-principle nutrient derived from dietary carbs
-fuel preference of most cells |
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Calorie
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-kilocarlorie
-equal to 1,000 calories -a calorie is the amount of heat needed to raise the temp of 1 g of water 1 degree C. (too small when discussing human body because of amount of heat involved) |
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basal metabolic rate (BMR)
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-reflection of the body's "idling speed" or the minimal waking rate of internal energy expenditure
-thyroid hormone is the primary but not the only determinant of the rate of basal metabolism * as thyroid hormone increases, the BMR increases |
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energy balance (neutral,positive, negative)
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*energy input=energy output
*energy in food consumed = external work + internal heat production +/- stored energy Neutral- if the amnt of energy in food intake equals the amnt of energy expended by the muscles in performing external work plus the basal internal energy expenditure that eventually appears as body heat; body weight constant Positive- amnt of energy in food intake is greater than the amnt of energy expended by means of external work and internal functioning. extra energy is stored in adipose tissue; body weight increases Negative- energy from food is less than body's immediate energy requirements. body must use stored energy; body weight decrease |
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creatine phosphate
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-first energy storehouse tapped at the onset of contractile activity
-contains high-energy phosphate group that can be donated directly to ADP to form ATP -energy released when the bond between phosphate and creatine is broken (hydrolysis) -the energy released can be donated directinly to ADP to form ATP as well -catalyzed by muscle-cell enzyme creatine kinase -whole process is reversible; energy and phosphate from ATP can be transferred to creatine to form creatine phosphate -most energy stored in muscle is in creatine pools -ATP can be formed rapidly |
