muscle+contraction+1


 * __How Does a Muscle Contraction Work?__**

Animation of Muscle Contraction

1) An efferent neuron stimulates an effector (muscle) by way of action potential 2) Neuron triggers the release of Calcium ions into the sarcoplasm 3) Calcium combines with troponin on the actin (aka thin filament), causing the shape of the troponin to change shape 4) The change in shape causes the tropomyosin to move away from the binding site* 5) Myosin then binds with the actin and, in a trigger like fashion, causes the muscle to contract**


 * Usually tropomyosin blocks the binding cites for actin and myosin. So, in order for the muscle contraction to be possible, troponin must be moved.
 * ATP provides the energy for the contraction

http://www.teachpe.com/anatomy/sliding_filament_1a.jpg


 * Muscle contraction decreases the size of...**

-the I-Band -the H-Zone


 * The A-band remains the same**