A gradual potential is first produced to depolarize the axon, action potentials are all or nothing so if the electrical signal is weak it will not produce a potential action since it does not reach the threshold value, “they are called acute subthreshold potentials” (Guyton & Hall, 2006); however the graded potentials add up, this is called summation and the axon hillock decides if the potential as a whole is higher than the threshold value and if the electrical signal exceeds the threshold which is around -55 mV a potential d is generated action (figure 2). This causes the cell to become slightly depolarized because Na+ ions flow through the few voltage-gated sodium ions that are open, which causes more voltage-gated sodium channels to open; “This results in positive feedback and an explosive self-amplifying depolarization.” At this point the “membrane is more permeable to Na+” (Willmer, et al., 2005). The membrane potential changes from “-70 mV to +50 mV” (Willmer, et al., 2005), sodium ion channels are inactivated and potassium ion channels are activated and K+ ions flow out of the cell repolarizing the membrane. The membrane becomes hyperpolarized when the voltage-gated potassium channels remain open, the resting potential is restored by the sodium-potassium pump, and the voltage-gated potassium channels close. So the signal