We know that the sum of the measures of any triangle is 180 degrees. Using the fact that angle A + angle B + angle C = 180 degrees, we can find the measure of angle C. angle A = 40. angle B = 60. angle C = we don't know.
When a depolarization wave reaches the synaptic end bulb of a presynaptic neuron, the NEXT event is diffusion of calcium ions into the cell A neurotransmitter that allows sodium ions to leak into a postsynaptic neuron causes
This means that some event (a stimulus) causes the resting potential to move toward 0 mV. When the depolarization reaches about -55 mV a neuron will fire an action potential. This is the threshold. If the neuron does not reach this critical threshold level, then no action potential will fire.