cellneuron

Cellneuron, commonly called a neuron or nerve cell, is the basic signaling unit of the nervous system. Neurons are specialized for receiving, integrating, and transmitting information through electrical and chemical signals. They form interconnected networks that underlie sensation, movement, cognition, and autonomic functions. Neurons communicate at synapses with other neurons, muscle cells, or gland cells via neurotransmitters.

A typical neuron consists of a soma (cell body) containing the nucleus, dendrites that receive inputs, and an axon that conducts impulses away from the soma. The axon ends at synaptic terminals. Many axons are insulated by glial-derived myelin, which increases conduction velocity through saltatory conduction at nodes of Ranvier. The cytoskeleton, mitochondria, and ion channels support excitability and signaling.

Neurons communicate primarily by membrane potential changes. A resting potential around -60 to -70 mV exists, and an action potential is triggered when depolarization reaches threshold, propagating along the axon and releasing neurotransmitters at the synapse. Neuron types include sensory (afferent), interneurons, and motor (efferent) neurons. Neurotransmitters such as glutamate, GABA, acetylcholine, and monoamines modulate postsynaptic activity. Synaptic plasticity underlies learning and memory.

Developmentally, neurons arise from neural progenitors, extend processes, and form circuits during embryogenesis. Most neurons are not replaced in adulthood, though limited neurogenesis occurs in certain regions. Neuronal dysfunction or loss contributes to many neurological disorders, while advances in imaging, electrophysiology, and neuroengineering continue to illuminate neuronal function.