The âline of actual controlâ between China and India in Arunachal Pradesh, which the Chinese refer to as South Tibet, is not as tense as the one in Kashmir. Talks between the two countries aimed at resolving the border issue have been going on for ten years and 15 rounds.
An excitatory postsynaptic potential, a type of graded potential, occurs because of the influx of Na+ through chemically gated channels in the receptive region, or postsynaptiâ¦c membrane, of a neuron.
The Na+ leaking into the cell (called the Na+ influx) causes the membrane potential to increase (become less negative). When the membrane potential crosses a threshold value (usually about -65mV), suddenly a whole lot more of Na+ channels are opened.There is a sudden rush of Na+ into the cell causing a rapid spike in the membrane potential. This can go up to 20mV. This influx of Na+ is the start of the action potential/impulse.When the voltage reaches the peak, Na+ channels are closed off due to the voltage. At the same time, these closed Na+ channels are inactivated temporarily and cannot be stimulated to open again. This is known as the absolute refractory period.ust think of it sitting there doing nothing. =p All cells have a membrane potential, which is the voltage across it's membranes. This is due to the difference in concentrations of ions inside and outside of the cells.