Class, CLICK HERE for a very good animation/explanation of the Cross-Bridge (S1 units) Movement during Muscle Contraction

CLICK HERE for a great explanation of sarcomere shortening

Here is a Sequence of Basic Muscle Summary Events We Have Covered Up to this Point. Please Learn and Quiz Yourself Below to see if you can put these Events in Correct Order.
1. Impulse arrives at neuromuscular junction

2. Acetylcholine (ACh) released and motor end plate depolarizes

3. Impulse travels t-tubules to sarcoplasmic reticulum (SR)

4. Calciums ions (Ca2+) are released

5. Ca2+ binds with troponin

6. Tropomyosin shifts, binding sites available

7. ATPase splits ATP to ADP + Pi + Energy

8. S1 unit binds actin

9. Power Stroke

10. Impulse stops, Ca2+ pumped back into SR

11. Tropomyosin returns over binding sites
Here is a Sequence NOT IN CORRECT order. Please Print out and see if you can put in correct order (we will do in class quiz as well).
Tropomyosin returns over binding sites

Impulse arrives at neuromuscular junction

Impulse stops, Ca2+ pumped back into SR

Acetylcholine (ACh) released and motor end plate depolarizes

Power Stroke

Impulse travels t-tubules to sarcoplasmic reticulum

S1 unit binds actin

Calciums ions (Ca2+) are released

ATPase splits ATP to ADP + Pi + Energy

Tropomyosin shifts, binding sites available

Ca2+ binds with troponin
Ex Phys Home