1. Energy Metabolism Flashcards
What is ATP?
Energy source of muscles
Required to power all forms of biological work
Stored as creatine phosphate in muscles
How can ATP be produce anaerobically?
ADP and Pi and H+ = ATP and H20
PCr and ADP and H+ = ATP and Cr
What if I cant remember any of this cause ive not done it from school?
Biochemistry of exercise textbook
What are the bi-products of anaerobic glycolysis
Hydrogen ions and lactate
What can be sadi about glycolysis and fatty acid metabolism?
They complement each other and work at the same time.
How does ATP allow for muscle contraction?
Myosin ATPase splits ATP and the energy produced isused for muscle contraction. Increased when actin and myosin i sjoined
Cross bridge cycline continues as long as calcium remains at a sufficient level
What is rigor mortis?
Actin and myosin cannot seperate due to lack of ATP within the body
What limits power supply within the body?
The time during which ATP hydrolysis can occur
Phosphocreatine hydrolysis and lactate formation are quickest
Fat and glucose oxidation are slowest
What is fatigue?
An inability to maintain a given level of phsyical performance
What are some causes of fatigue?
Decreased energy supply
Intereference with contractile mechanisms
Disruption at NMJ
Dehydration
Central fatigue
Discuss glycogens role in fatigue in anaerobic exercise
Not a rate limiting factor in initial anaerobic exercise but it will be rate limiting after repeated intense bursts of exercise.
May see selective fatigue in Type II fibres
What does the data from spiret et al demonstrate about muscles and fatigue?
Contractile force fatigues over time, almost inversely proportional to lactate levels
Phosphocreatine diminishes rapidly over the first 25 seconds
ATP slowly decreases but is fairly maintained
Hypothesises that Fatigue is a protective mechanism for protecting ATP
How does hydrogen ion concentration impact exercise capabilities?
Increased hydrogen ions reduces acidosis
Inhibits rate limiting enzymes of glycolysis
Impairs calcium’s role in excitation contraction coupling
Impair cross bridge cycling
How does lactic acid affect exercisew capabilites?
Lactic dissociates into lactic and hydrogen ions
Leads to intracellular changes in muscle and contractile mechanism
Decreases stored high energy phosphates
Decreases glycolytic enzyme activity
Ionic imbalance
Decreased neural transmission (signalling of muscle contraction).
What may inhibit muscle excitation contraction coupling
Phosphate accumulation
Decreased Calcium transport
Increased binding to sarcoplasmic reticulum
Increased hydrogen ions, decreased pH
Efflux of potassium (important for osmolality and cell volume)
