Närvikonduktiiooni

Närvikonduktiiooni, also known as nerve conduction, refers to the process by which electrical signals are transmitted along nerve fibers. This process is fundamental to the functioning of the nervous system, enabling communication between the brain, spinal cord, and the rest of the body.

The electrical signal that travels along a nerve fiber is called an action potential. This potential is generated when the membrane of the neuron undergoes a rapid change in its electrical charge. This change is initiated by the influx of sodium ions into the cell, followed by the efflux of potassium ions. This wave of depolarization and repolarization propagates along the axon, the long projection of a nerve cell.

In myelinated nerve fibers, which are covered by a fatty insulating sheath called myelin, nerve conduction is significantly faster. This is due to a phenomenon called saltatory conduction, where the action potential "jumps" from one gap in the myelin sheath, known as a Node of Ranvier, to the next. This rapid transmission is crucial for quick reflexes and complex motor functions. Unmyelinated fibers, lacking myelin, conduct signals much more slowly.

Nerve conduction studies, or electroneuromyography (ENMG), are diagnostic tests used to evaluate the speed and strength of nerve impulses. These tests can help identify nerve damage or diseases that affect nerve function, such as peripheral neuropathy or carpal tunnel syndrome. By measuring the time it takes for an electrical signal to travel a certain distance along a nerve, clinicians can assess the health of the nerve.