Final answer:
The resting membrane potential is the voltage across a neuron's membrane at rest, characterized by the interior of the cell being around -70 mV compared to the outside. This is due to ion concentration gradients and the action of the sodium-potassium pump, which uses ATP to maintain this potential. The neuron remains ready to respond to signals thanks to this potential difference.
Step-by-step explanation:
Resting Membrane Potential Explained
The resting membrane potential is a crucial concept in understanding how neurons operate. This electric potential exists across the neuron's plasma membrane when it is not actively transmitting a signal. The inside of a resting neuron is approximately 70 millivolts (mV) more negative than the outside, typically around -70 mV. This is because of concentration gradients of ions, like potassium (K+) and sodium (Na+), across the neural cell membrane, established by ion channels and pumps, particularly the sodium-potassium pump.
Potassium ions, being in higher concentration inside the cell, exit the neuron through potassium channels, leading to a net negative charge inside. Sodium ions, in contrast, are higher in concentration outside the neuron and enter more slowly due to fewer sodium leak channels. This movement of positive ions out of the cell contributes to the negative resting potential inside. The sodium-potassium pump uses ATP to transport ions against their concentration gradients, further establishing the resting potential by moving two K+ ions into the cell and extruding three Na+ ions out of it for each ATP molecule consumed.
It's important to note that up to 50 percent of a neuron's ATP may be used to maintain this electrical difference, which is vital for the neuron's ability to respond to and transmit signals.