Definition: A portion of a line which starts at a point and goes off in a particular direction to infinity. Try this Adjust the ray below by dragging an orange dot and see how the ray AB behaves. Point A is the ray's endpoint.
Plant cell cross-section, showing the membrane. Animal cell cross-section, showing the membrane. Resting membrane potential is the difference in voltage of the fluids inside a cell and outside a cell, which is usually between -70 to -80 millivolts (mV). View slideshow of images above.
The resting potential of the neuron refers to the difference between the voltage inside and outside the neuron. The resting potential of the average neuron is around -70 millivolts, indicating that the inside of the cell is 70 millivolts less than the outside of the cell.