26 Peer Pointers

The Steps of Muscle Contraction.

1.) Action Potential allows an electrical impulse to be sent out from neurons to the Neuromuscular junction (where a neuron meets a muscle fiber). Acetylcholine is released.
2.) AcH binds to the receptors on the Sarcolemma. The impulse spreads along the Sarcolemma and travels down the T-tubules. Calcium is released.
3.) Calcium binds to Troponin (a protein on Actin) this causes Tropomyosin to roll over, exposing Myosin binding sites on Actin.
4.) Myosin heads bind to the exposed sites on Actin, forming a cross bridge. Then pivot using ATP.
5) As the sites pivot and move toward the M line which causes muscle contraction.

3 Main things are needed for Muscle Contractions:
1- Stimulation from the Nervous System
2-Calcium
3-ATP