week 5: The muscular system: Acute muscular responses to exercise: response to exercise Flashcards
upon the onset of (aerobic) exercise, what happens to ATP turnover
increased in a square-wave fashion in response to steady state work-rates
three main muscular responses to exercise
1 metabolic pathways
2 aerobic performance: O2 extraction, blood flow
3 molecular signalling pathways
oxygen deficit
oxygen consumption increases at a slower rate to meet energetic demands until a steady state is achieved
due to the oxygen lag, how are immediate energetic requirements (that are not met by aerobic metabolism) met
supplemented by anaerobic pathways
increase in skeletal muscle blood flow
at rest: 5mL/min/100g
well trained ind: 400mL/min/100g
(per 100g muscle mass)
why does skeletal muscle blood flow need to increase rapidly
so mitochondria can increase oxygen uptake and ATP provision via oxidative phosphorylation
what does a greater number of capillaries surrounding each fibre improve
O2 diffusion (Fick’s law)
substrate delivery
removal of waste product
comparison of trained vs untrained individuals capillaries
trained individuals have a higher capillary to muscle fibre ration compared to untrained
arteriole venus oxygen difference (a-VO2) change as a response to exercise
increases as performance goes towards max
why does a-VO2 difference increase
muscle is extracting more arteriole oxygenated blood
what does a-VO2 difference increase result in
ability to increase muscle- oxygen consumption
what does high VO2 indicate
high mitochondrial O2 consumption
more reliance on aerobic metabolism
less reliance on anaerobic metabolism which is associated with fatigue
different types of exercise can activate
activates important signalling proteins which turn on transcriptional activators which can then translocate into nucleus, increase exercise related proteins
