Alpha motor neuron

This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. Please help improve this article by introducing more precise citations. (November 2013) (Learn how and when to remove this message)

Alpha motor neuron
Alpha motor neurons are derived from the basal plate (basal lamina) of the developing embryo.
Identifiers
NeuroLex ID	sao1154704263
TH	H2.00.01.0.00008
FMA	83664
Anatomical terms of neuroanatomy [edit on Wikidata]

Alpha (α) motor neurons (also called alpha motoneurons), are large, multipolar lower motor neurons of the brainstem and spinal cord. They innervate extrafusal muscle fibers of skeletal muscle and are directly responsible for initiating their contraction. Alpha motor neurons are distinct from gamma motor neurons, which innervate intrafusal muscle fibers of muscle spindles.

While their cell bodies are found in the central nervous system (CNS), α motor neurons are also considered part of the somatic nervous system—a branch of the peripheral nervous system (PNS)—because their axons extend into the periphery to innervate skeletal muscles.

An alpha motor neuron and the muscle fibers it innervates comprise a motor unit. A motor neuron pool contains the cell bodies of all the alpha motor neurons involved in contracting a single muscle.