Animation of skeletal muscle contraction [back]

Upon stimulation, calcium is released from the sarcoplasmic reticulum, due to inhibition of the calcium pumps. The process demonstrated in the animation will repeat as long as calcium is present, pulling the actin chains toward the center of the sarcomere and the Z-lines closer together. Scroll down to see the text below the illustration.  Click here to see illustration of myofilament organization.