Question

Would lowering a neurons intracellular (k) by 1 mMs have the same effect on resting membrane potential as raising the extracellular fluid (k) by 1mM?

Answer 1

A neuron at rest is negatively charged: the inside of a cell is approximately 70 millivolts more negative than the outside (−70 mV, note that this number varies by neuron type and by species). This voltage is called the resting membrane potential; it is caused by differences in the concentrations of ions inside and outside the cell. If the membrane were equally permeable to all ions, each type of ion would flow across the membrane and the system would reach equilibrium. Because ions cannot simply cross the membrane at will, there are different concentrations of several ions inside and outside the cell, The difference in the number of positively charged potassium ions (K⁺) inside and outside the cell dominates the resting membrane potential ( The negative charge within the cell is created by the cell membrane is more permeable to potassium ion movement than the sodium ion movement. The resting membrane potential is a result of different concentrations inside and outside the cell. The difference in the number of positively charged potassium ions (K⁺) inside and outside the cell dominates the resting membrane potential

If the extracellular potassium concentration surrounding a myocyte increase, then the potassium gradient across the cell membrane decreases, and therefore the resting membrane potential will become more positive. Similarly, if extracellular potassium decreases, the resting membrane potential will be more negative. become more positive. Similarly, if extracellular potassium decreases, the resting membrane potential will be more negative.

The resting potential is determined by concentration gradients of ions across the membrane and by membrane permeability to each type of ion. ... Ions move down their gradients via channels, leading to a separation of charge that creates the resting potential.