puhkepotentsiaalista

Puhkepotentsiaalista refers to the resting potential of a cell, a concept particularly relevant in cell biology and neuroscience. It describes the electrical potential difference across the plasma membrane of a cell when it is not stimulated or actively transmitting a signal. This potential is primarily established by the uneven distribution of ions, such as sodium (Na+) and potassium (K+), across the cell membrane and the selective permeability of the membrane to these ions.

The resting potential is maintained by the action of ion pumps, most notably the sodium-potassium pump, which actively transports ions against their concentration gradients, and by ion channels that allow specific ions to diffuse across the membrane. The concentration of potassium ions is typically higher inside the cell, while sodium ions are more concentrated outside. Due to the presence of more potassium leak channels than sodium leak channels, potassium ions tend to diffuse out of the cell more readily than sodium ions diffuse in, creating a net negative charge inside the cell relative to the outside.

This negative electrical potential inside the cell is crucial for cellular functions. For excitable cells like neurons and muscle cells, the resting potential serves as a baseline from which action potentials can be generated. Changes in the resting potential, known as depolarization or hyperpolarization, are the basis of electrical signaling in these cells. The precise value of the resting potential varies among different cell types but is typically in the range of -60 to -80 millivolts.