Lesson 22 Flashcards
what does ATP supply depend on?
availability of oxygen and organic energy sources
anaerobic fermentation
enables cells to produce ATP in the absence of oxygen; yields little ATP and lactic acid
aerobic respiration
uses the mitochondria to produce far more ATP than fermentation; does not generate lactate; requires a continual supply of oxygen for the mitochondria
what is the primary energy source for short term maximum acitivity?
anaerobic fermentation
what is the primary energy source for long term activity?
aerobic metabolism
oxygen is briefly supplied by _____ inside muscle cells during short, intense exercise
myoglobin
muscle meets most ATP demand by doing what?
borrowing phosphate groups from other molecules and transferring them to ADP
creatine kinase
enzyme that obtains a phosphate from a phosphate storage molecule creatine phosphate and gives it to ADP
phosphagen system
the combination of ATP and CP which provides nearly all energy for short bursts of activity
as the phosphagen system is exhausted, muscles shift to….
anaerobic fermentation
anaerobic threshold
aka lactate threshold
- point at which lactate becomes detectable in the blood
glycogen-lactate system
the pathway from glycogen to lactate
- produces enough ATP from 30 to 40 seconds of maximum activity
after about 40 sec, the respiratory and cardiovascular system do what?
they start delivering oxygen fast enough for aerobic respiration to meet most of the muscle’s ATP demand
after 3-4 min, the rate of oxygen consumption levels off to a _____ _____ where aerobic ATP production keeps pace with deman
steady state
muscle fatigue
progressive weakness from prolonged used of muscles
fatigue in high-intensity (short duration) exercise results from two things
- potassium accumulation
- ADP and Pi accumulation
fatigue in low-intensity (long duration) exercise results from these three things
- fuel depletion
- electrolyte loss
- central fatigue
potassium accumulation
in the T tubules reduces muscle cell excitability by interfering with Ca2+ release from the sarcoplasmic reticulum
ADP and Pi accumulation
slows cross-bridge movements, inhibit Ca2+ release and decrease force production in myofibrils
fuel depletion
glycogen and glucose levels decline
electrolyte loss
lost through sweat, decreased muscle excitability
central fatigue
ammonia released by active muscle inhibits motor neurons and cause less motor signals from the brain to the muscle cells
maximum oxygen uptake (VO2 max)
the point at which the rate of oxygen consumption plateaus and does not increase further with added work
what is the major determinant of one’s ability to maintain high-intensity exercise for more than 4-5min?
maximun oxygen uptake
