Muscles 2 Flashcards
What increases during aerobic endurance training?
Fatigue resistance
Blood capillaries
What increases in anaerobic endurance training?
Myofibril size (more myofilaments)
Diameter of muscle fibre
Where is the energy provided from in first 2 mins of exercise?
Stored energy
Anaerobic glycolysis
What do muscle cells have a reserve of?
ATP
Phosphocreatine
The build up of what stimulates metabolic pathways in energy release?
ADP
AMP
Phosphate
What happens to creatine at rest?
Recycled into phosphocreatine in mitochondria
Glycogenesis of glucose produces …
Glucose 1 phosphate
At what state does glucose enter glycolysis?
Glucose 6 phosphate
What takes up glucose from blood?
GLUT4
Why do muscles fatigue?
H+ from lactic acid lowers the cells pH
Lactic acid accumulates from pyruvate
Advantage of anaerobic conditions
Produces ATP in the absence of 02
Disadvantage of anaerobic conditions
ATP yield is low and toxic products are generated
What are the results of anaerobic conditions?
2 ATP
Lactic acid
What do aerobic conditions produce?
38 molecules of ATP
What happens when tissue oxygen delivery increases in aerobic energy release?
Oxidative phosphorylation energy production is stimulated
What feeds oxidative phosphorylation during aerobic energy release?
Lactate is converted back to pyruvate
What releases lactate into circulation?
Type IIx fibres
What happens during extended periods of aerobic energy release?
Lactate and alanine can be used by the liver to generate glucose.
Redistribution of glycogen stores.
Mobilisation of non-muscle lipids, increasing in circulating fatty acids taken up by muscle.
Breakdown of triacylglycerol stored in muscles.
Define muscle fatigue?
Inability to maintain a desired power output.
Decline in force and velocity of muscle shortening
Define central fatigue
Deficient drive of motor cortical output
Define peripheral fatigue
Decrease in contractile strength of muscle fibres
Define high-frequency fatigue
Alteration in cell Na/K balance, particularly in type II fibres
Define low-frequency fatigue
Reduced release of Ca2+ from sarcoplasmic reticulum, particularly type I fibres
Define ATP depletion
Intense stimulation causing large drops in ATP near cross bridge formation and ATPases
What does lactic acid build up cause?
Cellular acidification
What is glycogen depletion?
Lack of glycogen leads to lack of glucose
‘Hitting a wall’
