Process of Muscle Contraction

These flashcards cover the process of muscle contraction, including the roles of calcium ions, myosin, actin, ATP, and the re-cocking of the myosin head.

What role do calcium ions play in muscle contraction?

Calcium ions diffuse into myofibrils from the sarcoplasmic reticulum, bind to tropomyosin, causing it to move and exposing the binding sites on actin.

What forms when myosin heads attach to actin?

An actin-myosin cross bridge is formed.

What happens during the power stroke?

The myosin head bends, pulling the actin filament along while releasing ADP.

What causes myosin heads to detach from actin?

A new ATP molecule attaches to the myosin head, causing it to detach from the actin binding site.

What is the function of ATPase in muscle contraction?

ATPase hydrolyzes ATP to ADP and Pi, providing energy needed to re-cock the myosin head for the next contraction.

What occurs when muscle impulses stop?

Calcium ions are actively transported back to the sarcoplasmic reticulum and tropomyosin returns to its original shape.