Delivery of stimulus above threshold intensity leads to a constant amplitude of AP and is known as:

All or none principle - - Once AP, is elicited at any point on membrane of normal fiber, depolarization process travels over entire membrane if conditions are right, but it doesn't travel at all if conditions are not right. This is all or none principle. Relative refractory period: - It is the time, at which muscle is difficult to excite than normal but can be excited by very strong excitatory signal. Absolute refractory period: - Period during which 2nd action potential cannot be elicited, even with strong stimulus . Electronic potential: - Work per unit of charge required to move a charge from reference point to specified point is called electric potential.