Muscle Contraction

Kaylee Hennessey            November 22, 2013       Period A

The Mechanism of Muscle Contraction

Texas A&M University

1 Page

Summary of the Article

The following steps are involved in muscle contraction:

1. Reflexes from the spinal cord or instructions from the brain cause nerve cells to initiate a reaction

2. A motor neuron is activated, and action potential passes out of the spinal cord

3. Action potential is conveyed to a numerous amount of places on the motor unit

4. ACh is released into synaptic clefts on the surface of the muscle fiber

5. ACh causes an action potential on the muscle fiber surface, dragging in separate directions

The Sliding Filament Theory

6. Action potential spreads into the muscle fiber through each transverse tubule

7. Sarcoplasmic reticulum releases calcium ions

8. Calcium ions result in movement of tropomin and tropomyosin on thin filaments. Myosin molecules swivel the filaments, which is the driving force of muscle contraction.

In conclusion, the nervous system plays a large part in the contraction and relaxation of muscles.