IN CLASS MUSCLE PHYS Flashcards
Three sources of ATP for muscle contraction
-phosphorylation of ATP for muscle contraction
-OP of ADP in mito
-Phosphorylation of ADP by glycolysis in cytosol
Time stamps for OP of ADP
5-10: draws nutrients from muscle glycogen
30 min: blood glucose and fatty acids
>30: blood fatty acids dominate
SO
rate of fatigue, rate of contraction, recover time
slow, slow, slow
SO
type of movement, motor neuron size, myglobin
low and long intensity, smallest, high (red color)
FOG
myoglobin, contraction velocity, fatigue
high (red color), fast, more resistant
FOG
type of movement, recovery time
aerobic/endurance activities, faster
FG
fatigue, type of movement, recovery time
least resistant to fatigue, powerlifting/soritning, fast
FG
motor neuron, myoglobin
largest motor neuron, no myoglobin (white )
What does the duration of contraction depend on?
the time cytosolic calcium remains elevated allowing the XBs to continue to cycle
What is muscle fatigue?
tension decreases even though stimulation occurs
What causes skeletal muscle fatigue?
-decrease in ATP production
-cell can no longer complete XB cycle
-build up of metabolites
-Mass action effect of ADP and Pi
Build up of metabolites
Aerobic: CO2 H2O
Anaerobic: lactic acid
MG and H decrease RYR calcium release, reuptake storage by SR and decrease calcium sensitivity of thin filament proteins
Mass action of ADP and Pi
these two things directly inhibit the power stroke motion of the myosin cross bridge, decreasing shortening velocity and impairs relaxation
What causes mass action effect
ADP and Pi build up because ATP is used to move the XV and you are burning alot of ATP
-when there is buildup more ATP will not be hydrolyzed leading to it
