Olfactory_receptor_neuron

Olfactory receptor neuron
Labels in German. "Zellen" = "cell","riech" = "smell", "Riechnerv" = olfactory nerve, "cillien" = cilia.
Location	olfactory epithelium in the nose
Function	Detect traces of chemicals in inhaled air (sense of smell)
Neurotransmitter	Glutamate
Morphology	Bipolar sensory receptor
Presynaptic connections	None
Postsynaptic connections	Olfactory bulb
Gray\'s	subject #223 996

Plan of olfactory neurons.

An olfactory receptor neuron, also called an olfactory sensory neuron, is the primary transduction cell in the olfactory system.

Contents 1 In vertebrates 1.1 Structure 1.2 Function 2 Image:Headline text[[Image:Example.jpgInsert footnote text here]] 3 In insects 4 See also 5 External links

In vertebrates

Humans have about 5 million olfactory receptor neurons. In vertebrates, olfactory receptor neurons reside on the olfactory epithelium in the nasal cavity. These cells are bipolar neurons with a dendrite facing the interior space of the nasal cavity and an axon that travels along the olfactory nerve to the olfactory bulb.

Structure

Many tiny hair-like cilia protrude from the olfactory receptor cell\'s dendrite into the mucus covering the surface of the olfactory epithelium. The surface of these cilia is covered with olfactory receptors, a type of G protein-coupled receptor. Each olfactory receptor cell expresses only one type of olfactory receptor, but many separate olfactory receptor cells express olfactory receptors which bind the same set of odors. The axons of olfactory receptor cells which bind the same odors glomeruli in the olfactory bulb.

Function

A given olfactory receptor can bind to a variety of odor molecules with varying affinities. The activated olfactory receptor in turn activates the intracellular G-protein GOLF (GNAL), and adenylate cyclase and production of Cyclic AMP opens ion channels in the cell membrane, resulting in an influx of sodium and calcium ions into the cell. This influx of positive ions causes the neuron to depolarize, generating an action potential.

[[Media:\'Strike-through textStrike-through text===Regeneration === Individual olfactory receptor neurons are replaced approximately every 40 days by neural stem cells residing in the olfa

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ctory epithelium. The regeneration of olfactory receptor cells, as one of the only few instances of adult neurogenesis in the central nervous system, has raised considerable interest in dissecting the pathways for neural development and differentiation in adult organisms.\']]#REDIRECT [[
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In insects

In insects, olfactory receptor neurons typically reside on the antenna. Much like in vertebrates, axons from the sensory neurons converge into glomeruli in the antennal lobe.

See also

• Chemoreceptor
• Sensory receptor

External links

• olfactory+receptor+cells at eMedicine Dictionary
• c_18/12224417 at Dorland\'s Medical Dictionary

v • d • e Sensory system: Olfactory system/Olfaction
Olfactory bulb • Olfactory nerve • Olfactory epithelium • Glomeruli • Olfactory mucosa • Olfactory receptor neurons • Mitral cells • Piriform cortex
Rhinencephalon • Olfactory tract • Olfactory trigone

v • d • e Histology: nervous tissue
Neurons (gray matter)	soma, axon (axon hillock, axoplasm, axolemma, neurofibril/neurofilament), dendrite (Nissl body, dendritic spine, apical dendrite, basal dendrite) types (bipolar, pseudounipolar, multipolar, pyramidal, Purkinje, granule)
Afferent nerve/Sensory nerve/Sensory neuron	GSA, GVA, SSA, SVA, fibers (Ia, Ib or Golgi, II or Aβ, III or Aδ or fast pain, IV or C or slow pain)
Efferent nerve/Motor nerve/Motor neuron	GSE, GVE, SVE, Upper motor neuron, Lower motor neuron (α motorneuron, γ motorneuron)
Synapses	neuropil, synaptic vesicle, neuromuscular junction, electrical synapse - Interneuron (Renshaw)
Sensory receptors	Free nerve ending, Meissner\'s corpuscle, Merkel nerve ending, Muscle spindle, Pacinian corpuscle, Ruffini ending, Olfactory receptor neuron, Photoreceptor cell, Hair cell, Taste bud
Glial cells	astrocyte, oligodendrocyte, ependymal cells, microglia, radial glia
Myelination (white matter)	Schwann cell, oligodendrocyte, nodes of Ranvier, internode, Schmidt-Lanterman incisures, neurolemma
Related connective tissues	epineurium, perineurium, endoneurium, nerve fascicle, meninges

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