axon reflex

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ax·on re·flex

a response elicited by peripheral nerve stimulation; attributed to impulses traveling proximally from the stimulation site along motor axons, encountering a branch point, and then passing distally down the other branch to activate local arterioles (to cause vasodilation) or muscle (to cause contractions). Latency of the response decreases with more proximal stimulation; axon reflex is eliminated by axon degeneration or strong stimuli but not by proximal anesthetic blocks of the nerve.

axon reflex

Etymology: Gk, axon, axle
a neuron reflex in which an afferent impulse travels along a nerve fiber away from the cell body until it reaches a branching, where it is diverted to an end organ without entering the cell body. It does not involve a complete reflex arc, and therefore it is not a true reflex.

axon reflex

A localised response executed by a bifucated axon, where activation of one limb of the axon causes excitation of its collateral, resulting in the release of neurotransmitters—e.g., calcitonin gene-related peptide, and substance P—producing effects on innervated cells.
Axon reflex effects
Submucosal vasodilation, duodenal secretion of bicarbonates, mast-cell degranulation.


the process of a nerve cell along which impulses travel away from the cell body. It branches at its termination, forming synapses at other nerve cells or effector organs. Many axons are covered by a myelin sheath formed from the cell membrane of a glial or Schwann cell.

axon hillock
the elevation on the perikaryon from which the axon emerges.
axon reflex
a nerve impulse conducted through nerve pathways limited to the single axon, without the participation of a nerve cell or synapse. Not a true reflex.
axon telodendrion
extensive terminal branches of the axon before terminating on the effector organ.
axon terminals
the axonal structure capable of forming a synapse with another axon.