nervledningen

Nervledningen is the process by which nerve impulses are transmitted within the nervous system. It encompasses the electrical signaling along neurons as well as the transmission of signals across synapses. The term is commonly used in physiological descriptions and clinical neurophysiology, where nerve conduction studies measure the speed and strength of signal transmission in peripheral nerves.

During an action potential, voltage-gated sodium channels open, depolarizing the membrane, followed by potassium channels that restore the resting potential. Propagation occurs as the depolarization of one segment triggers the next. In myelinated fibers, the myelin sheath increases conduction velocity by forcing the impulse to jump between nodes of Ranvier (saltatory conduction). Myelin is produced by oligodendrocytes in the central nervous system and by Schwann cells in the peripheral nervous system.

Conduction velocity is influenced by axon diameter, degree of myelination, and temperature. Unmyelinated fibers conduct slowly (roughly 0.5–2 m/s), while large myelinated fibers can reach speeds up to about 120 m/s. Nerve conduction studies quantify these properties to assess nerve function.

Disruptions of nervledningen can indicate neurological disorders such as demyelinating diseases, axonal neuropathies, or compressive injuries. Clinically, nerve conduction studies, sometimes combined with electromyography, aid in diagnosis and monitoring. Limitations include variability with age, temperature, and technical factors.

See also: neuron, action potential, synapse, myelination, nerve conduction velocity.