MODEL
Slide the filaments
Change sarcomere length and inspect A band, I band and overlap.
Model
The Z discs move closer as thin filaments slide past thick filaments. Filaments retain their lengths.
A band: 1.6 µm
H zone: 0.5 µm
Combined thin-only regions: 0.9 µm
Schematic geometry: each thin filament is 1.0 µm and the thick filament 1.6 µm. It shows overlap and band changes, not force or cross-bridge counts.
Explain what you observed
Do the filaments themselves shorten?
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Connect this activity with your lesson notes and chapter practice.
Read a related learning guide →Practise Support & Movement →Open the student notes folder ↗Concepts and sources
Curriculum connections: 9.4, 9.5. Selected concepts.
Read the supporting source ↗PMDC curriculum ↗Questions and explanations are original teaching material; these are not official exam questions.