bioelectricity

Bioelectricity refers to electrical phenomena in living organisms. It arises from charge separation and ion movements across cell membranes, producing membrane potentials and electric currents that coordinate cellular processes. The principal medium is the intracellular and extracellular fluids separated by lipid membranes containing ion channels, pumps such as the Na+/K+-ATPase, and other transport proteins.

Most cells maintain a resting membrane potential, typically ranging from about -40 to -90 millivolts, depending on cell type and ion gradients. When stimulated, excitable cells may generate action potentials: rapid depolarizations caused by the opening of voltage-gated sodium channels, followed by repolarization mediated by potassium channels and other currents. Action potentials propagate along axons or muscle fibers, enabling rapid communication and coordinated contraction.

Beyond excitable tissues, bioelectric signals arise from ion movements and field effects in non-neuronal cells. These signals influence development, wound healing, and regeneration, and they can direct cell migration, orientation, and pattern formation during embryogenesis.

Organisms exhibit specialized electrical systems. Electric fish use electrocytes to produce high-voltage discharges for communication and navigation. Plants and some algae generate slower, long-distance electrical signals in response to stimuli, providing rapid signaling without nerves.

Measurement techniques include microelectrode recordings, patch-clamp methods, and voltage-sensitive dyes. The study of bioelectricity has historical roots in experiments by Galvani and Volta and informs modern neuroscience, cardiology, and the emerging field of bioelectronic medicine, including devices such as pacemakers and neural stimulators.