Answer: Muscle contractions stimulate the release of calcium
from sarcoplasmic reticulum.
Explanation:
During muscle contractions, calcium is released from its store into the sarcoplasma, where it goes and bind to troponin protein complex . This causes the troponin to change its shape and remove the tropomyosin from the myosin-binding site for exposure. Myosin then binds to actin active site and form a cross-bridge or power stroke due the presence of ATP.
Calcium functions in regulating muscle contractions and relaxations in response to stimulus.
