Question

What happens when Ca2+ are released in the cytoplasm of the muscle cell?

Answer 1

Explanation:

Travels down a motor neuron and down T-tubules into muscle fibre.

-Ca2+ released from SR.

-Tropomyosin moves and uncovers myosin binding site on actin.

-Crossbridge formation = myosin binds to actin.

-Power stroke = stored energy in myosin head is released and myosin head pivots.

-Cross-bridge breaks as ATP binds myosin head.

-Myosin reactivation = myosin head splits ATP into ADP and Pi and 're-cocks' ready for another contraction cycle.

-Contraction cycle repeats if Ca2+ is still present. Bind, power stroke, detach and extend.

Answer 2

Answer:

pls refer to the attachment above