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Encyclopedia > Axon hillock
The arrow labeled "axon" is pointing directly at the axon hillock.
The arrow labeled "axon" is pointing directly at the axon hillock.

The Axon Hillock is the anatomical part of a neuron that connects the cell body called soma (biology) to the axon. It is attributed as the place where Inhibitory Postsynaptic Potentials (IPSPs) and Excitatory Postsynaptic Potentials (EPSPs) from numerous synaptic inputs on the dendrites or cell body summate. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ... The soma is the bulbous end of a neuron, containing the nucleus. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... Inhibitory Postsynaptic Potential is commonly abbreviated to Currently there is more information available under the heading synapse. ... Excitatory Postsynaptic Potential is generally abbreviated to Much information is available under the heading synapse, but this is a different concept. ... The area in a neuron (usually on the dendrites or cell body) where presynaptic neurons synapse. ...


It is electrophysiologically equivalent to the 'initial segment where the summated membrane potential reaches the triggering threshold, an action potential propagates through the rest of the axon (and "backwards" towards the dendrites as seen in backpropagation). The triggering is due to positive feedback between highly crowded voltage gated sodium channels, which are present at the critical density at the axon hillock (and nodes of ranvier) but not in the soma. Electrophysiology is the study of the electrical properties of biological cells and tissues. ... This article or section is in need of attention from an expert on the subject. ... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... Backpropagation is a supervised learning technique used for training artificial neural networks. ... Sodium channels (also known as voltage-gated sodium channels) are integral membrane proteins that are localized in and conduct sodium ions (Na+) through a cells plasma membrane. ...


Cell biologically it is the neuronal equivalent of tight junction as it acts as a barrier for lateral diffusion of transmembrane proteins (and GPI anchored proteins like thy1 across it[1].) A transmembrane protein is an integral membrane protein that spans from the internal to the external surface of the biological membrane or lipid bilayer in which it is embedded. ... Thy-1 or CD90 is a 25–37 kDa heavily N-glycosylated, glycophosphatidylinositol (GPI) anchored conserved cell surface protein with a single V-like immunoglobulin domain, originally discovered as a thymocyte antigen. ...


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Nervous tissue - edit
Neurons (gray matter): soma, axon (axon hillock, axoplasm, axolemma, neurofibril/neurofilament), dendrite (Nissl body, dendritic spine)
types (bipolar, pseudounipolar, multipolar, pyramidal, Purkinje, Renshaw, granule)

Synapses: neuropil, boutons, synaptic vesicle, neuromuscular junction, electrical synapse The University of Oklahoma, often called OU or Oklahoma, is a coeducational public research university located in the U.S. state of Oklahoma. ... The Spinal cord nested in the vertebral column. ... Nervous tissue is the fourth major class of vertebrate tissue. ... Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ... Grey matter is a category of nervous tissue with many nerve cell bodies and few myelinated axons. ... The soma is the bulbous end of a neuron, containing the nucleus. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... Axoplasm is the cytoplasm of the axon of a neuron. ... The axolemma is the membrane of a neurons axon. ... Intermediate filaments are one component of the cytoskeleton - important structural components of living cells. ... The term Dendrite stems from the Greek word dendron (literally “tree”), and typically refers to the branched projections of a neuron that act to conduct the electrical stimulation received from other cells to and from the cell body, or soma of the neuron from which the dendrites project. ... Image of a Nissl-stained histological section through the rodent hippocampus showing various classes of neurons. ... Close up of the dendrite of a striatal medium spiny neuron. ... As a part of the retina, the bipolar cell exists between photoreceptors (rod cells and cone cells) and ganglion cells. ... Pseudounipolar cells (Pseudo- false, uni- one) are sensory neurons in the peripheral nervous system. ... The multipolar neuron possesses a single (usually long) axon and many dendrites, allowing for the integration of a great deal of information from other neurons. ... A pyramidal cell (or pyramidal neuron, or projection neuron) is a multipolar neuron located in the hippocampus and cerebral cortex. ... Drawing of pigeon Purkinje cells (A) by Santiago Ramon y Cajal Purkinje cells are a class of GABAergic neuron located in the cerebellar cortex. ... Renshaw cells are located in the spinal cord horn. ... In neuroscience, granule cells are tiny cells found within the granular layer of the cerebellum. ... Illustration of the major elements in a prototypical synapse. ... Neuropil is the feltwork of unmyelinated neuronal processes (axonal and dendritic) within the gray matter of the central nervous system Traditionally, when pathologists looked at brain tissue they concentrated on neurons (the active functioning cells of the brain), glial cells and axons (especially in white matter, which is mostly composed... In a synapse, a bouton (or synaptic button, or presynaptic button) is a protuberance at the pre-synaptic nerve terminal where two axons connect with each other. ... In a neuron, synaptic vesicles, also called neurotransmitter vesicles, store the various neurotransmitters that are released during calcium-regulated exocytosis at the presynaptic terminal into the synaptic cleft of a synapse. ... A neuromuscular junction is the junction of the axon terminal of a motoneuron with the motor end plate, the highly-excitable region of muscle fiber plasma membrane responsible for initiation of action potentials across the muscles surface. ... An electrical synapse is a mechanical and electrically conductive link between two abutting neurons that is formed at a narrow gap between the pre- and postsynaptic cells known as a gap junction. ...


Sensory receptors: Free nerve ending, Meissner's corpuscle, Merkel nerve ending, Muscle spindle, Pacinian corpuscle, Ruffini ending, Olfactory receptor neuron, Photoreceptor, Hair cell, Taste bud In a sensory system, a sensory receptor is a structure that recognizes a stimulus in the internal or external environment of an organism. ... NERVE ENDINGS SUCK PENIS!!! ... Meissners corpuscles (discovered by the anatomist Georg Meissner (1829-1903) are a type of mechanoreceptor and more specifically, a tactile corpuscle(corpusculum tactus). ... Merkel nerve endings are mechanoreceptors found in the skin and mucosa of vertebrates that provide touch information to the brain. ... A muscle spindle is a specialized muscle structure innervated by both sensory and motor neuron axons. ... A Pacinian corpuscle is a structure that functions as a mechanoreceptor. ... Ruffini Endings are one of the four main cutaneous mechanoreceptors. ... An olfactory receptor neuron, also called an olfactory sensory neuron, is the primary transduction cell for olfaction in the olfactory system. ... A photoreceptor is a specialized form of cell (specifically, neuron) that is capable of phototransduction. ... Hair cells are the sensory cells of both the auditory system and the vestibular system in all vertebrates. ... Taste buds are small structures on the upper surface of the tongue, soft palate, and epiglottis that provide information about the taste of food being eaten. ...


Glial cells: astrocyte, ependymal cells, microglia, radial glia This article or section does not cite its references or sources. ... Astrocytes, also known as astroglia, are characteristic star-shaped glial cells in the brain. ... It has been suggested that this article or section be merged with Ependyma. ... Microglia are a type of glial cell that act as the immune cells of the Central nervous system (CNS). ... Radial glial cells are a pivotal cell type in the developing CNS involved in key developmental processes, ranging from patterning and neuronal migration to their newly described role as precursors during neurogenesis. ...


Myelination (white matter): Schwann cell, oligodendrocyte, nodes of Ranvier, internode, Schmidt-Lanterman incisures, neurolemma In neuroscience, myelin is an electrically insulating phospholipid layer that surrounds the axons of many neurons. ... White matter is one of the two main solid components of the central nervous system. ... Named after the German physiologist Theodor Schwann, Schwann cells are a variety of neuroglia that mainly provide myelin insulation to axons in the peripheral nervous system of jawed vertebrates. ... Oligodendrocytes (from Greek literally meaning few tree cells), or oligodendroglia (Greek, few tree glue)[1], are a variety of neuroglia. ... This article is about Anatomy, for the musical group see Nodes of Ranvier (band) Nodes of Ranvier are regularly spaced gaps in the myelin sheath around an axon or nerve fiber. ... The portion of nerve fiber between two Nodes of Ranvier is called an internodal segment (or internode). ... Oblique clefts may be seen in the medullary sheath, subdividing it into irregular portions, which are termed Schmidt-Lanterman incisures (or clefts of schmidt-lanterman, segments of Lantermann, medullary segments. ... Neurolemma (spelled also neurolema, neurilemma and neurilema, and used interchangeably with epineurium) is the insulating myelin layer that surrounds an individual peripheral nerve fiber. ...


closely related Connective tissue: epineurium, perineurium, endoneurium, nerve fascicle, meninges In the human body there are four types of tissue: (1) Epithelial, (2) Connective, (3) Muscle, and (4) Nervous Tissue. ... Neurolemma (spelled also neurolema, neurilemma and neurilema, and used interchangeably with epineurium) is the insulating myelin layer that surrounds an individual peripheral nerve fiber. ... In a nerve fiber, the tubular sheath of the funiculi, perineurium, is a fine, smooth, transparent membrane, which may be easily separated, in the form of a tube, from the fibers it encloses; in structure it is made up of connective tissue, which has a distinctly lamellar arrangement. ... The nerve fibers are held together and supported within the funiculus by delicate connective tissue, called the endoneurium. ... A small bundle of fibers, enclosed in a tubular sheath, is called a funiculus; if the nerve is of small size, it may consist only of a single funiculus; but if large, the funiculi are collected together into larger bundles or nerve fascicles, which are bound together in a common... The meninges (singular meninx) are the system of membranes that envelop the central nervous system. ...


  Results from FactBites:
 
Axon hillock - Wikipedia, the free encyclopedia (89 words)
The axon hillock is the anotomical part of a neuron that connects the cell body to the axon.
It is attributed as the place where EPSPs from numerous synaptic inputs on the dendrites or cell body accumulate.
If the accumulated potential reaches the threashold, an action potential propagates through the rest of the axon (or "backwards" towards the dendrites as seen in backpropagation).
  More results at FactBites »

 
 

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