Dorsal root ganglion

Dorsal root ganglion
DRG Chicken e7.jpg
This is a dorsal root ganglion (DRG) from a chicken embryo (around stage of day 7) after incubation overnight in NGF growth medium stained with anti-neurofilament antibody. Axons growing out of the ganglion are visible.
Gray675.png
A spinal nerve with its anterior and posterior roots. The dorsal root ganglion is the "spinal ganglion", following the posterior/dorsal root.
Latin ganglion sensorium nervi spinalis
Gray's subject #185 750
Precursor neural crest
MeSH Spinal+Ganglia
Code TA A14.2.00.006

In anatomy and neuroscience, a dorsal root ganglion (or spinal ganglion) is a nodule on a dorsal root that contains cell bodies of neurons in afferent spinal nerves.

Contents

Unique unipolar structure

The axons of dorsal root ganglion neurons are known as afferents. In the peripheral nervous system, afferents refer to the axons that relay sensory information into the central nervous system (i.e. the brain and the spinal cord). These neurons are of the pseudo-unipolar type, meaning they have an axon with two branches that act as a single axon, often referred to as a distal process and a proximal process.


Note: the neuron can consist of three parts:

1. Dendrite that receives the information and relays it to the Soma), or cell body.
2. Soma - the cell body of the neuron
3. Axon: which relays information from the soma.

In a neuron, the dendrite receives information from another neuron's axon at the synapse, and the axon sends information to the next neuron's dendrites, even though the dendrite may be covered with myelin.


Unlike the majority of neurons found in the central nervous system, an action potential in dorsal root ganglion neuron may initiate in the distal process in the periphery, bypass the cell body, and continue to propagate along the proximal process until reaching the synaptic terminal in the dorsal horn of the spinal cord.

Distal section

The distal section of the axon may either be a bare nerve ending or encapsulated by a structure that helps relay specific information to nerve. For example, a Meissner's corpuscle or Pacinian corpuscle may encapsulate the nerve ending, rendering the distal process sensitive to mechanical stimulation, such as stroking or vibration, respectively. [1]

Location

The dorsal root ganglia lie along the vertebral column by the spine.

Embryology

The dorsal root ganglia develops in the embryo from neural crest cells, not neural tube. Hence, the spinal ganglia can be regarded as gray matter of the spinal cord that became translocated to the periphery.

Nociception

Proton-sensing G protein-coupled receptors are expressed by DRG sensory neurons and might play a role in acid-induced nociception.[2]

References

  1. ^ Kandel ER, Schwartz JH, Jessell TM. Principles of Neural Science, 4th ed., p.431-433. McGraw-Hill, New York (2000). ISBN 0-8385-7701-6
  2. ^ Huang CW, Tzeng JN, Chen YJ, Tsai WF, Chen CC, Sun WH (2007). "Nociceptors of dorsal root ganglion express proton-sensing G-protein-coupled receptors". Mol. Cell. Neurosci. 36 (2): 195–210. doi:10.1016/j.mcn.2007.06.010. PMID 17720533. 

See also

Additional images

External links


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Look at other dictionaries:

  • dorsal root ganglion — n SPINAL GANGLION * * * g. sensorium nervi spinalis …   Medical dictionary

  • dorsal-root ganglion — noun : spinal ganglion …   Useful english dictionary

  • Dorsal root — Infobox Anatomy Name = PAGENAME Latin = radix posterior GraySubject = 208 GrayPage = 916 Caption = The formation of the spinal nerve from the dorsal and ventral roots Caption2 = System = Precursor = MeshName = Dorsal+Roots MeshNumber =… …   Wikipedia

  • Ganglion — In anatomy, a ganglion (pl. ganglia ) is a tissue mass. [DorlandsDict|four/000043442|ganglion] NeurologyIn neurological contexts, ganglia are composed mainly of somata and dendritic structures that often interconnect with other ganglia to form a… …   Wikipedia

  • Dorsal column nuclei — {{{Name}}} Present at the junction between the spinal cord and medulla oblongata, the dorsal column nuclei consist of paired gracile and cuneate nuclei (labels 6 and 7, respectively). System …   Wikipedia

  • root — 1. The primary or beginning portion of any part, as of a nerve at its origin from the brainstem or spinal cord. SYN: radix (1) [TA]. 2. SYN: r. of tooth. 3. The descending underground …   Medical dictionary

  • Ganglion — The celebrated 2nd century Greek physician Galen ((c. 130 201 A.D.) who lived and worked in Rome first used the word ganglion to denote a nerve complex. Ganglion still is used to refer to an aggregation of nerve cell bodies. Another use of the… …   Medical dictionary

  • ganglion — ganglial, gangliar, adj. /gang glee euhn/, n., pl. ganglia / glee euh/, ganglions. 1. Anat. a. a mass of nerve tissue existing outside the central nervous system. b. any of certain masses of gray matter in the brain, as the basal ganglia. 2.… …   Universalium

  • ganglion sensorium nervi spinalis — [TA] spinal ganglion: the ganglion found on the posterior root of each spinal nerve, composed of the unipolar nerve cell bodies of the sensory neurons of the nerve. Called also g. spinale and dorsal or posterior root g. Ganglion sensorium nervi… …   Medical dictionary

  • spinal ganglion — (= dorsal root ganglion) Enlargement of the dorsal root of the spinal cord containing cell bodies of afferent spinal neurons. Neural outgrowth from dorsal root ganglia has been studied extensively in vitro …   Dictionary of molecular biology

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