Anatomy & Physiology › Section I · Muscle tissue › Topic I.2
Fibre contraction and relaxation
Once calcium floods a muscle fibre, millions of tiny myosin heads start pulling on actin, each one powered by a molecule of ATP. This topic follows that pull from the switch that starts it to the pumps that end it, and asks where the fibre finds its ATP.
In this topic
- Picking up the signal
- The troponin-tropomyosin switch
- The sliding filament model
- The cross-bridge cycle
- Worked example: counting power strokes
- Relaxation, and rigor mortis
- Where ATP comes from
- Worked example: two routes to 300 ATP
- Fatigue and recovery
- Duchenne muscular dystrophy
- Common mistakes to avoid
- Key takeaways
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