Chapter 12 Muscle Physiology Flashcards
In a resting muscle fiber no ______ is present, therefore the myosin head group is blocking from binding to _____.
In resting muscle fiber state, what is bound to domains on headgroup?
What position is myosin head group in?
No calcium present
Blocks myosin from binding to actin
ADP and Pi is bound
Myosin is in cocked and ready position
Somatic motor neuron sends action potential to muscle cell it releases ______ from ______. The presence of this causes myosin to bind to ______.
Once this cross bridge binding occurs, ____ experiences an expulsion. This leads to a conformational change in myosin also called the___________ where the myosin head group goes from a ______ position to a ______ position.
Calcium released from SR
Ca+ present causes myosin head group to bind to actin.
Pi undergoes expulsion from head group. This leads to power stroke where head goes from cocked to flexed position
Expulsion of _____ upon myosin head group binding to actin in presence of calcium leads to power stroke.
The power stroke is the most energy _____ step. The energy required for the conformational change from the cocked to flexed position comes from the _________ of _____.
Power stroke causes the _____ filament to slide towards the center of the ________.
As sliding occurs from headgroup going from ______ to ______, _____ is released from headgroup.
Pi is released causes conformational change
Power stroke is most energy costly step
Hydrolysis of ATP: provides energy for power stroke
Power stroke: myosin head group binding slides actin towards middle of sarcomere.
Cocked to flexed state –> ADP is released
Expulsion of Pi leads to ________.
When filaments start to slide in power stroke, ____ is released.
____ binding causes myosin head group to detach from actin.
Power stroke
ADP
ATP
Once ATP binds to myosin head group, it detaches from actin. ATP then undergoes _________ to produce ____ and ____. This is referred to as the “______” of the myosin head as it prepares it for another cycle.
ATP hydrolysis produces the energy that is needed for ________.
ATP undergoes hydrolysis to create ADP and Pi/
‘Cocking of myosin head”
Produces energy for power stroke
