Axon

Definition

An axon is a long slender projection of a nerve cell or neuron found in most animals that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands. In certain sensory neurons, such as those for touch and warmth, the axons are called afferent nerve fibers and the electrical impulse travels along these from the periphery to the cell body and from the cell body to the spinal cord along another branch of the same axon. Axon dysfunction can be the cause of many inherited and many acquired neurological disorders that affect both the peripheral and central neurons. Nerve fibers are classed into three types – group A nerve fibers, group B nerve fibers, and group C nerve fibers. Groups A and B are myelinated, and group C is unmyelinated. These groups include both sensory fibers and motor fibers. Another classification groups only the sensory fibers into four categories: Type I, Type II, Type III, and Type IV.

Related concepts

A delta fiber Actin Action potential Active zone Afferent nerve fiber Alan Hodgkin Albert von Kölliker All-or-none law Alpha motor neuron American Psychological Association Amyloid-beta precursor protein Anatomical terminology Ancient Greek language Andrew Huxley Animal Ankyrin-3 Anterior spinothalamic tract Apical dendrite Association fiber Astrocyte Autapse Autonomic ganglion Autonomic nervous system Axolemma Axon (disambiguation)Axon guidance Axon hillock Axon terminal Axonal transport Axonotmesis Axoplasm Basal dendrite Beta motor neuron Bipolar neuron Brain-derived neurotrophic factor Bulbous corpuscle CLEC7A Caenorhabditis elegans Cell adhesion molecule Cell membrane Cell polarity Cellular extensions Central chromatolysis Central nervous system Cerebellar granule cell Cerebellum Cerebral hemisphere Cf.Chemical synapse Commissural fiber Concussion Connective tissue Contactin 2 Corpus callosum Cortical neurons Cutaneous mechanoreceptor Cytoplasm Cytoplasmic protrusion Cytoskeleton Decussation Demyelinating disease Dendrite Dendritic spine Development of the nervous system Diffuse axonal injury Dorsal ramus of spinal nerve Dorsal root ganglion Dorsal root of spinal nerve Dynein Efferent nerve fiber Electrical synapse Electrophysiology Endoneurium Ependyma Epineurium Exocytosis Extracellular matrix Extrafusal muscle fibers Fibronectin Filopodia Foundational Model of Anatomy Free nerve ending Funiculus (neuroanatomy)Gamma motor neuron Ganglionic eminence Ganglioside Gap junction General Electric General somatic afferent fibers General somatic efferent fibers General visceral afferent fibers General visceral efferent fibers Giant axonal neuropathy Giant squid Giovanna Morigi Glia Glycoprotein Golgi tendon organ Granule cell Gray matter Gray ramus communicans Grey matter Group A nerve fiber Group B nerve fiber Group B nerve fibres Group C nerve fiber Growth cone Guidepost cells Hair cell Herbert Gasser Herbert Spencer Gasser Hippocampus Hodgkin–Huxley model Human brain Immunoglobulin Insect Intermediate filaments Interneuron Internodal segment Intrafusal muscle fibers Invertebrate Ion channel Jet propulsion Joseph Erlanger Kinesin Lamellipodium Laminin Lateral spinothalamic tract Leech Lemniscus (anatomy)Leukodystrophy Literal translation Longfin inshore squid Louis-Antoine Ranvier Lower motor neuron Macrophage Mechanoreceptor Medical Subject Headings Medium spiny neuron Membrane protein Meninges Merkel nerve ending Microglia Micrometre Microtubule Mitochondria Model organism Motor neuron Motor protein Motor proteins Multiple sclerosis Multipolar neuron Muscle fiber Muscle spindle Myelin Myelin-associated glycoprotein Myelin basic protein Myelin incisure Myelin sheath NMNAT2 Nerve Nerve conduction velocity Nerve fascicle Nerve fiber Nerve growth factor Nerve guidance conduit Nerve injury Nerve tract Nervous system Nervous tissue Netrin Neural cell adhesion molecule Neural coding Neural tissue Neurapraxia Neurilemma Neurite Neurodegenerative disease Neurofilament Neuroglia Neurological disorder Neuromuscular junction Neuron Neuronal tracing Neuropil Neuroregeneration Neurotmesis Neurotoxicity Neurotransmitter Neurotrophic factors Neurotrophin-3 Nissl bodies Nissl body Nobel Prize in Physiology or Medicine Nociceptor Node of Ranvier Nodes of Ranvier Olfactory receptor neuron Oligodendrocyte Oligodendrocyte progenitor cell Otto Friedrich Karl Deiters Oxford English Dictionary PI3K Pacinian corpuscle Parallel fiber Penaeidae Perineurium Peripheral nervous system Peripheral neuropathy Perlecan Persistent vegetative state Phosphatase Phosphatidylinositol (3,4,5)-trisphosphate Photoreceptor cell Pioneer axon Pioneer neuron Place cells Placentalia Postganglionic fibers Postganglionic nerve fibers Postsynaptic density Preganglionic fibers Preganglionic nerve fibers Projection fiber Proprioceptor Proteolipid protein Pseudounipolar neuron Purkinje cell Pyramidal cell Ramus communicans Rat Refractory period (physiology)Renshaw cell Reticulon 4 Rho family of GTPases Ribbon synapse Robert Remak Romanization of Ancient Greek Saltatory conduction Santiago Ramón y Cajal Satellite glial cell Scaffold protein Schizophrenia Schwann cell Sciatic nerve Sensory neuron Sensory receptor Sensory receptors Sialidase Single-unit recording Soma (biology)Special somatic afferent Special visceral afferent Special visceral efferent Spinal cord Squid giant axon Summation (neurophysiology)Synapse Synaptic vesicle Taber's Medical Dictionary Tactile corpuscle Tanycyte Taste receptor Telodendria Telodendron Tenascin Thermoreceptors Threshold potential Transmission electron micrograph Traumatic brain injuries Traumatic brain injury TrkA Trk receptor Type II sensory fiber Type Ia sensory fiber UNC-5 Unipolar neuron University of California, San Francisco Unmyelinated Upper motor neuron Ventral ramus of spinal nerve Ventral root of spinal nerve Voltage-gated sodium channel Von Economo neuron Wallerian degeneration Warmth receptors White matter White ramus communicans

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