Function of skeletal muscle organs Flashcards
twitch contraction
A quick jerk of a muscle produced as a result of a single, brief threshold stimulus (generally occurs only in experimental situations)
Latent phase
nerve impulse travels to the SR to trigger release of Ca++
ATP->ACh-> impulse
Contraction phase
Ca++ binds to troponin and sliding of filaments occurs
Relaxation phase
sliding of filaments ceases
Treppe: the staircase phenomenon
Gradual, steplike increase in the strength of contraction that is seen in a series of twitch contractions that occur 1 second apart
If the relaxation phase disappears completely
a contracture occurs
The muscle eventually responds with less-forceful contractions, and the relaxation phase
becomes shorter
Multiple wave summation
multiple twitch waves added together to sustain muscle tension for a longer time
Incomplete tetanus
very short periods of relaxation between peaks of tension
Tetanus
smooth, sustained contractions(normal)
Complete tetanus(normal)
twitch waves fuse into a single, sustained peak
The availability of Ca++ determines whether a muscle will contract; if Ca++ is continuously available
then contraction will be sustained