Biology / Unit 13 Bio 3115 short lesson, about 20 seconds
Sliding Filament Mechanism
Captions available
The idea
Myosin heads bind actin, pivot in a power stroke that pulls the actin filament inward, release, and re-bind further along, repeatedly shortening the sarcomere.
In practice
Repeated myosin power strokes ratchet the actin filament stepwise toward the sarcomere's center, like hand-over-hand rope-pulling.
Where people slip
Filament sliding pulls a sarcomere inward from both ends at once — it is not a one-directional tug.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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