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.
plasma membranes of cells, especially nerve and muscle cells, leads to a resting state in which. the cytosol is electrically polarized (negative) with respect to the extracellular fluid. This steady-. state electrical potential (voltage) difference across the cell membrane is known as the resting. membrane potential.