frog leg Flashcards
Why did the muscle require a stronger stimulation impulse to create the same twitch as a lower amount of stimulation on the sciatic nerve?
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what is the difference when muscle was stimulated vs sciatic nerve?
when nerve is stimulated AP is propagated down the axon and Ach is released from the axon terminal at the level of the muscle fiber
when muscle is stimulated AP is propagated amoung the muscle fibers and no Ach is released
define muscle twitch
the movement created by an AP stimulus
what would happen if Ca++ were applied to the muscle cell?
it could contribute to the sacroplasm’s Ca++ concentration, meaning a smaller amount of stimulation would create a larger twitch
define multiple-wave summation
as AP frequency is increased, the muscle has less of a chance to relax in between (Ca++ is not able to be taken up by the sarcoplasmic reticulum quickly enough) so subsequent twitches are stronger (to a certain extent) if AP frequency is high enough, muscle has no chance to relax in between (tetany) occurs
define treppe
a constant stimulus applied at a low frequency, creates muscle twitches of increasing tension because sarcoplasmic reticulum is unable to uptake Ca++ quickly enough to return to resting levels (0 Ca++ in sarcoplasm)
why does the gastrocnemius muscle need to be under an amount of tension to create a measurable muscle twitch?
to create the optimal overlap between the myosin and actin myofilaments
what would happen if no tension was applied to the gastrocnemius muscle?
the sarcomeres would already be “contracted” to their fullest extent an no cross-bridges could form
what would happen if the muscle was put under too much tension and then stimulation applied
the muscle twitch would be much smaller because many fewer cross-bridges would be able to form–the actin and myosin couldn’t “get a grip” to produce an efficient twitch
