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.
Hyperpolarization and depolarization. At rest, a typical neuron has a resting potential (potential across the membrane) of â60-60â60minus, 60 to â70-70â70minus, 70 millivolts. This means that the interior of the cell is negatively charged relative to the outside. See videos: Neuron resting potential description, Neuron resting potential mechanism.