Physiology of Muscle Contraction

Physiology of muscle contraction

Release of Acetylcholine

Action potential comes to nerve terminal, that potential open the voltage gated calcium channels at nerve terminal. The movement of calcium ion inside the cell. Vesicles filled with acetylcholine present at nerve terminal. Calcium evoked vesicle of Ach. Ach vesicles are ruptured and release Ach.

Activation of Ach Receptors

Two molecules of Ach Ach binding  to Ach receptor on the motor end plate. Voltage gated sodium channels are open and influx of sodium ion in muscle fibers. 

Production of Muscle Action Potential 

Numbers of sodium ion inside muscle fiber are increase and generate action potential that potential cause muscle contraction.

Sodium ions enter inside the cells and potassium ions comes out from cell, changes of ion produce electrical charge. Both interior and exterior of muscle cell become positively charge.

Membrane get depolarized, this depolarization cause contraction. 

When the muscle contraction is over, then acetylcholine destroyed by acetylcholinersterase. After this potassium ions move into the cell and sodium ions move out of the cell, this potential stage called repolarization. 

Physiology of Muscle Contraction Flow Chart