Specifically, once a muscle reaches complete tetatnus, is there any further benefit to force production by even further increasing the frequency of action potentials, or is the limit reached once there is any level of sustanined muscle contraction? If you kept increasing the action potential frequency without limit what would happen?
In: Biology
So muscle contraction is at its root based on muscle filaments sliding past each other, with proteins called myosins “rowing” across actin filaments.
With no action potential, there is no “rowing,” and the fibers arent even connected to each other, they have to hold onto each other for there to actually be tension held. If this rowing happens fast enough, there will either always be some connections holding this tension or the rowing will happen fast enough that due to inertia there wont even be a chance to fall back into this relaxed state. You can kind of think of it like a kayak tied to the shore with a rubber band, if the rower rows fast enough they can probably stretch the rubber band quite a bit, but unless they row fast they will probably get pulled back at least a little bit while they reset their row. But if they row faster, they can pull on the rubber band even faster.
Tetany occurs only when the inertia of the contraction is slower than the rate of contractions. But there is still a little bit of room to go faster here.
There should be a limit to the absolute speed at which myosin can undergo its cycle of activating then resetting, if the limit isnt the rate at which the action potential reset can occur.
Latest Answers