Muscle Physiology

Question 1

how is calcium removed from the SR in skeletal muscle?

Answer 1

1. action potential reaches the t-tubule
2. DHP receptor activates ryanodine receptor on the SR
3. Ca2+ released from SR
4. Ca2+ binds to troponin on actin and removes tropomyosin

Question 2

what is the cross-bridge cycling?

Answer 2

1) ATP attaches to myosin head to release it from actin
2) ATP hydrolysis to ADP +Pi
3) Lose Pi and add Ca2+ to bind myosin head to actin
4) lose ADP to cause power stroke

Question 3

which stage of the cross-bridge cycling causes rigor?

Answer 3

lack of ATP causes actin to stay stuck to myosin head