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10 Cards in this Set
- Front
- Back
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Major energy (ATP) consumption in mucle |
Sarcomeric myosin motor activity -> contraction - myosin ATPase Ion pumps - maintaining Ca++ (and other) concentration in muscle low |
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Muscle types |
Skeletal - slow twitch - fast twitch Cardiac |
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Skeletal muscle - slow twitch |
Predominately aerobic Highly vascularized High mitochondrial content High levels of intramuscular triglyceride Contains glycogen High levels of lipoprotein lipase (LPL) |
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Skeletal muscle - fast twitch |
Predominately anaerobic Low vascularization Low mitochondrial content High concentration of glycolytic enzymes Low intra-muscular triglyceride Major energy store is glycogen |
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Cardiac muscle |
Very aerobic Highly vascularized High mitochondrial content Oxidizes fatty acid well Oxidizes lactate well Low capacity for glycolysis Low glycogen stores |
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Fuel sources for muscle |
Glucose - Blood - Diet/liver (via glycogenolysis/gluconeogenesis) Glycogen - Local - Muscle glycogen stores FA - Blood - Adipose Tissue TAG - Local/Blood - Cellular TAG, diet (chylomicrons)/Liver (VLDL) - LPL Ketone bodies - Blood - Liver (β-oxidation) AA's - Blood - Diet Phospho-creatine - Local - Creatine kinase ADP - Local - Adenylate kinase |
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Rapid supply of muscle ATP (Anaerobic exercise) |
- 2ADP -> Adenylate Kinase -> ATP + AMP (-> AMPK -> FA oxidation) - Creatine <-> ATP, Creatine Kinase <-> C-Pi - AMP / Ca++ -> phosphorylase kinase -> -- glycogen phosphorylase -> Glycogenolysis (PKA-independent) - PFK (++AMP, Pi, NH3, --ATP, C-Pi) -> glycolysis |
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Fueling Aerobic Exercise |
Low intensity (slow-twitch) - FA - CAT1 - slow - Acetyl-CoA -> ACC -> Malonyl-Coa --| CAT1 - AMPK --| ACC High intensity - glucose |
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Post-exercise re-fueling |
Intake of sugar & AA's: - AMPK -> GLUT4 -> replenishing glycogen stores (insulin-independent) -> insulin spike -> muscle protein synthesis |
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Consequences of FA catabolism deficiency on muscle fuel usage |
Muscle usually depends on FA oxidation during rest & exercise CPTII deficiency -> greater usage of glucose |
