Lepopotentiaalissa

Lepopotentiaalissa refers to the resting potential of a cell. This is the membrane potential of a non-excited cell, meaning it is not actively sending or receiving signals. It is the baseline electrical state of a cell's membrane.

The resting potential is primarily established and maintained by the difference in ion concentrations across the cell membrane and the selective permeability of the membrane to these ions. Key ions involved include sodium (Na+), potassium (K+), chloride (Cl-), and large negatively charged organic molecules (anions). The sodium-potassium pump plays a crucial role by actively transporting three sodium ions out of the cell for every two potassium ions pumped into the cell, thus maintaining the electrochemical gradients.

The resting potential is typically negative inside the cell relative to the outside. This negativity arises because the cell membrane is more permeable to potassium ions, which tend to leak out of the cell down their concentration gradient, leaving behind a net negative charge. While sodium ions can also leak in, their inward movement is less significant in establishing the resting potential due to the membrane's lower permeability to them. The precise value of the resting potential varies between different cell types but is generally in the range of -60 to -80 millivolts. This state is essential for cellular functions and is the foundation upon which electrical excitability in cells like neurons and muscle cells is built.