Axon terminal - wikipedia Axon terminal Activity at an axon terminal : Neuron A is transmitting a signal at the axon terminal to neuron B ( receiving ). Features : 1. Mitochondrion. 2. Synaptic vesicle with neurotransmitters. 3. Autoreceptor. 4. Synapse with neurotransmitter released ( serotonin ). 5. Postsynaptic receptors activated by neurotransmitter ( induction of a postsynaptic potential ). 6. Calcium channel. 7. Exocytosis of a vesicle. 8. Recaptured neurotransmitter. Axon terminals ( also called synaptic boutons or terminal boutons ) are distal terminations of the telodendria ( branches ) of an axon. An axon, also called a nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses called action potentials away from the neuron 's cell body, or soma, in order to transmit those impulses to other neurons, muscle cells or glands. Neurons are interconnected in complex arrangements, and use electrochemical signals and neurotransmitter chemicals to transmit impulses from one neuron to the next ; axon terminals are separated from neighboring neurons by a small gap called a synapse, across which impulses are sent. The axon terminal, and the neuron from which it comes, is sometimes referred to as the `` presynaptic '' neuron. Contents 1 Nerve impulse release 2 Mapping activity 3 See also 4 References 5 Further reading Nerve impulse release Neurotransmitters are packaged into synaptic vesicles that cluster beneath the axon terminal membrane on the presynaptic side of a synapse. The axonal terminals are specialized to release the neurotransmitters of the presynaptic cell. The terminals release transmitter substances into a gap called the synaptic cleft between the terminals and the dendrites of the next neuron. The information is received by the dendrite receptors of the postsynaptic cell that are connected to it. Neurons do n't touch each other, but communicate across the synapse. The neurotransmitter molecule packages ( vesicles ) are created within the neuron, then travel down the axon to the distal axon terminal where they sit docked. Calcium ions then trigger a biochemical cascade which results in vesicles fusing with the presynaptic membrane and releasing their contents to the synaptic cleft within 180 μs of calcium entry. Triggered by the binding of the calcium ions, the synaptic vesicle proteins begin to move apart, resulting in the creation of a fusion pore. The presence of the pore allows for the release of neurotransmitter into the synaptic cleft. The process occurring at the axon terminal is exocytosis, which a cell uses to exude secretory vesicles out of the cell membrane. These membrane - bound vesicles contain soluble proteins to be secreted to the extracellular environment, as well as membrane proteins and lipids that are sent to become components of the cell membrane. Exocytosis in neuronal chemical synapses is Ca triggered and serves interneuronal signalling. Mapping activity Structure of a typical neuron Neuron Dendrite Soma Axon Nucleus Node of Ranvier Axon terminal Schwann cell Myelin sheath Dr. Wade Regehr, a Professor of Neurobiology at Harvard Medical School 's Department of Neurobiology, developed a method to physiologically see the synaptic activity that occurs in the brain. A dye alters the fluorescence properties when attached to calcium. Using fluorescence - microscopy techniques calcium levels are detected, and therefore the influx of calcium in the presynaptic neuron. Regehr 's laboratory specializes in pre-synaptic calcium dynamics which occurs at the axon terminals. Regehr studies the implication of calcium Ca as it affects synaptic strength. By studying the physiological process and mechanisms, a further understanding is made of neurological disorders such as epilepsy, schizophrenia and major depressive disorder, as well as memory and learning. See also Telodendron Endoplasmic reticulum Golgi apparatus Micelle Membrane nanotube Endocytosis Synaptic vesicle Vesicle ( biology ) Chemical synapse Vesicular monoamine transporter Axon References Jump up ^ `` Axon Terminal ''. Medical Dictionary Online. Retrieved February 6, 2013. Jump up ^ Foster, Sally. `` Axon Terminal - Synaptic Vesicle - Neurotransmitter ''. Retrieved February 6, 2013. Jump up ^ Llinás R, Steinberg IZ, Walton K ( 1981 ). `` Relationship between presynaptic calcium current and postsynaptic potential in squid giant synapse ''. Biophysical Journal. 33 ( 3 ) : 323 -- 51. doi : 10.1016 / S0006 - 3495 ( 81 ) 84899 - 0. PMC 1327434. PMID 6261850. Jump up ^ Carlson, 2007, p. 56 Jump up ^ Chudler, Eric H. ( November 24, 2011 ). `` Neuroscience for kids Neurotransmitters and Neuroactive Peptides ''. Archived from the original on December 18, 2008. Retrieved February 6, 2013. Jump up ^ Sauber, Colleen. `` Focus October 20 - Neurobiology VISUALIZING THE SYNAPTIC CONNECTION ''. Archived from the original on 2006 - 09 - 01. Retrieved July 3, 2013. Jump up ^ Regehr, Wade ( 1999 -- 2008 ). `` Wade Regehr, Ph. D ''. Archived from the original on February 18, 2010. Retrieved July 3, 2013. Jump up ^ President and Fellows of Harvard College ( 2008 ). `` The Neurobiology Department at Harvard Medical School ''. Archived from the original on 20 December 2008. Retrieved July 3, 2013. Jump up ^ `` NINDS Announces New Javits Neuroscience Investigator Awardees '' ( Press release ). National Institute of Neurological Disorders and Stroke. May 4, 2005. Archived from the original on January 17, 2009. Retrieved February 6, 2013. Jump up ^ `` Scholar Awards ''. The McKnight Endowment Fund for Neuroscience. Archived from the original on 2004 - 05 - 08. Retrieved July 3, 2013. Further reading Cragg, Stephanie J. ; Greenfield, Susan A. ( 1997 ). `` Differential Autoreceptor Control of Somatodendritic and Axon Terminal Dopamine Release in Substantia Nigra, Ventral Tegmental Area, and Striatum ''. The Journal of Neuroscience. 17 ( 15 ) : 5738 -- 46. PMID 9221772. Vaquero, Cecilia F ; de la Villa, Pedro ( 1999 ). `` Localisation of the GABAC receptors at the axon terminal of the rod bipolar cells of the mouse retina ''. Neuroscience Research. 35 ( 1 ) : 1 -- 7. doi : 10.1016 / S0168 - 0102 ( 99 ) 00050 - 4. PMID 10555158. Roffler - Tarlov, Suzanne ; Beart, P.M. ; O'Gorman, Stephen ; Sidman, Richard L. ( 1979 ). `` Neurochemical and morphological consequences of axon terminal degeneration in cerebellar deep nuclei of mice with inherited purkinje cell degeneration ''. Brain Research. 168 ( 1 ) : 75 -- 95. doi : 10.1016 / 0006 - 8993 ( 79 ) 90129 - X. PMID 455087. Yagi T, Kaneko A ( 1988 ). `` The axon terminal of goldfish retinal horizontal cells : A low membrane conductance measured in solitary preparations and its implication to the signal conduction from the soma ''. Journal of Neurophysiology. 59 ( 2 ) : 482 -- 94. PMID 3351572. Membrane transport Mechanisms for chemical transport through biological membranes Passive transport Simple diffusion ( or non-mediated transport ) Facilitated diffusion Osmosis Channels Carriers Active transport Uniporter Symporter Antiporter Primary active transport Secondary active transport Cytosis Endocytosis Efferocytosis Non-specific, adsorptive pinocytosis Phagocytosis Pinocytosis Potocytosis Receptor - mediated endocytosis Transcytosis Exocytosis Degranulation Nervous tissue CNS Tissue Types Grey matter White matter Projection fibers Association fiber Commissural fiber Lemniscus Funiculus Fasciculus Nerve tract Decussation Commissure Neuropil Meninges Cell Types Neuronal Pyramidal Purkinje Granule Glial insulating : Myelination : Oligodendrocyte other Astrocyte Radial glial cell Ependymal cells Tanycyte Microglia PNS General Dorsal Root Ganglion Ramus Ventral Root Ramus Ramus communicans Gray White Autonomic ganglion ( Preganglionic nerve fibers Postganglionic nerve fibers ) Connective tissues Epineurium Perineurium Endoneurium Nerve fascicle Neuroglia Myelination : Schwann cell Neurolemma Myelin incisure Node of Ranvier Internodal segment Satellite glial cell Neurons / nerve fibers Parts Soma Axon hillock Axon Telodendron Axon terminals Axoplasm Axolemma Neurofibril / neurofilament Dendrite Nissl body Dendritic spine Apical dendrite / Basal dendrite Types Bipolar Unipolar Pseudounipolar Multipolar Interneuron Renshaw Afferent nerve fiber / Sensory neuron GSA GVA SSA SVA fibers Ia or Aα Ib or Golgi or Aα II or Aβ and Aγ III or Aδ or fast pain IV or C or slow pain Efferent nerve fiber / Motor neuron GSE GVE SVE Upper motor neuron Lower motor neuron α motorneuron β motorneuron γ motorneuron Termination Synapse Electrical synapse / Gap junction Chemical synapse Synaptic vesicle Active zone Postsynaptic density Autapse Ribbon synapse Neuromuscular junction Sensory receptors Meissner 's corpuscle Merkel nerve ending Pacinian corpuscle Ruffini ending Muscle spindle Free nerve ending Nociceptor Olfactory receptor neuron Photoreceptor cell Hair cell Taste bud Retrieved from `` https://en.wikipedia.org/w/index.php?title=Axon_terminal&oldid=814690025 '' Categories : Neurohistology Hidden categories : Accuracy disputes from February 2013 All articles lacking reliable references Articles lacking reliable references from February 2013 All pages needing factual verification Wikipedia articles needing factual verification from February 2013 All articles with unsourced statements Articles with unsourced statements from February 2013 Talk Contents About Wikipedia Čeština Deutsch Español Français Galego Português Română Slovenščina Türkçe Edit links This page was last edited on 10 December 2017, at 09 : 18. 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Question: the blank is the tiny gap between the axon terminal and the next neuron
Answer: synapse