Lateral grey column

Source: Wikipedia, the free encyclopedia.
Lateral grey column (lateral horn)
Cross-Section of the Spinal Cord
Details
Identifiers
Latincornu laterale medullae spinalis
MeSHD066152
TA98A14.1.02.132
A14.1.02.022
TA26077
FMA256536
Anatomical terminology
The four main divisions of the spinal column, from top to bottom: cervical, thoracic, lumbar, and sacral

The lateral grey column (lateral column, lateral cornu, lateral horn of spinal cord, intermediolateral column) is one of the three

thoracic and upper lumbar[1] regions (specifically T1-L2) of the postero-lateral part of the anterior grey column
.

Background information

Nervous system

The

commissures (tracts that cross the brain's midline).[2]

Sympathetic nervous system

The nervous system is divided into the central nervous system (brain and spinal cord) and the peripheral nervous system (everything else). The peripheral nervous system is divided into the somatic nervous system (voluntary processes) and the autonomic nervous system (involuntary processes). The autonomic nervous system is divided into the parasympathetic nervous system (normal functioning) and the sympathetic nervous system (emergency functioning).[3] The lateral grey column mediates the functions of the sympathetic nervous system.

Spinal cord

The

thoracic, lumbar, and sacral.[4]

Structure

The lateral grey column is present at 17 levels of the spinal cord, specifically through levels T1-L2 (sympathetic outflow) as well as through levels S2-S4 (parasympathetic outflow).[5] Both these segments are located within the first thoracic vertebra to the first or second lumbar vertebra as the spinal cord ends here and the nerves form the cauda equina.

Pathway from the lateral grey column to target tissue

The lateral grey column is composed of sympathetic preganglionic visceral motor neurons which are part of the

noradrenaline storage granules and could be divided into four types. Type one terminals contained a few large and many small granular vesicles, and type two terminals had many large vesicles and barely noticeable granules. Type three terminals contained small, spherical vesicles and no granules, and type four were the rarest terminals that had flattened vesicles with small and large granules.[6]

The cells of the intermediolateral cell column are fusiform or star-shaped, and of a medium size.

intermediolateral cell column exists at vertebral levels T1 - L2 and mediates the entire sympathetic innervation of the body.[5] In the upper part of the cervical region and lower part of the medulla oblongata
, as well as in the third and fourth sacral vertebrae, this column is again differentiated.

Functions

The lateral grey column's connections mediate the functions of the sympathetic nervous system (SNS), which changes cardiac, pulmonary, hepatic (liver), and gastrointestinal activities to prepare the body for emergency situations

bronchioles of the lungs relax, allowing more oxygen to enter the bloodstream. Heart rate increases to ensure all cells are supplied quickly with the substances they need. The liver produces glucose (sugar) to fuel the muscles.[8] Blood vessels contract (vasoconstriction), which reduces bleeding and conserves body heat (the exception is blood vessels fueling large muscles that would be used in running or fighting). The pupils dilate, improving vision.[9] Perspiration increases in certain areas of the body (the purpose of this is not yet fully understood, but there is some evidence that the odor produced by this sweat serves as a signal to other individuals).[10]

Sympathetic

Sympathetic nervous system

The lateral grey column plays an important role in the

preganglionic neurons in the sympathetic nervous system originate in the lateral grey column.[5] Neurons in the upper and middle thoracic segments control sympathetic activity in organs in the head and thorax, while neurons in the lower thoracic and upper lumbar segments control abdominal and pelvic organs and targets in the lower extremities.[2]

Slightly myelinated preganglionic fibers (aka

ganglia connected by nerve fibers.[5]

Most often, the fibers from the lateral grey column will travel along the sympathetic trunk until they synapse on one of the trunk's ganglia, which then passes on the information via

cardiac nerves
that innervate the heart, reach the target organ directly, without first joining a gray ramus communicans.

Other fibers from lateral grey column neurons pass through the sympathetic trunk without synapsing there. The greater

superior mesenteric ganglia, which innervates the superior mesenteric artery, and to the aorticorenal ganglion.[5] The least, or lowest, splanchnic nerve connects the T12 level to the renal plexus.[11] The lumbar splanchnic nerves from the upper two lumbar segments synapse in the abdomen on the inferior mesenteric ganglia, associated with the inferior mesenteric artery.[5] In addition, some thoracic fibers in the splanchnic nerves innervate the adrenal medulla, a ganglion in the abdomen that mediates the sympathetic response to stress.[2]

Axons from the lateral grey column release acetylcholine at their synapses. This can excite or inhibit the postsynaptic cell, depending on the type of acetylcholine receptor in its membrane. Postganglionic cells (that is, nerve cells innervated in ganglia by lateral column neurons) typically release norepinephrine (noradrenaline) on their targets; these synapses can also be either excitatory or inhibitory.[1]

The lateral grey column receives input signals from preganglionic, myelinated fibers from

paravertebral ganglia (in the sympathetic chain), white rami communicantes, and dorsal roots to synapse on cells of the intermediolateral cell column in the lateral horn.[4]

Lateral grey column nerve cells also receive signals from the brainstem and from neurons in the hypothalamus, a brain area involved in mediating many physiological functions and emotional states.[12]

Clinical significance

Horner's syndrome is characterized by small pupils, sunken eyes, partially drooping eyelid, and dryness of the skin on the face. It is caused by problems in autonomic pathways such as damage to the lateral grey column.[1]

Progressive autonomic failure is a disease associated with autonomic disturbances due to selective

neuronal degeneration.[13] A study estimated the number of nerve cells in the lateral grey columns of 21 people with progressive autonomic failure in comparison with a control group. This same study found that an average of 75 percent of the lateral column cells were lost in people with progressive autonomic failure.[14]

autonomic dysfunction.[15] A study did a comparison with the lateral grey column nerve cell count between 15 cases of patients with MSA and a control group. All cases of MSA had lost over 50 percent of their lateral horn cells which shows the involvement of the intermediolateral columns in MSA.[16]

subacute combined degeneration) is the result of a vitamin B12 deficiency and is associated with pernicious anemia.[17] The disease is characterized by the degeneration of both the lateral and posterior columns, which results in symptoms such as a spastic ataxic gait and paranoia.[18] Patients may also feel tingling or weakness in their limbs and torso.[17]

References

Public domain This article incorporates text in the public domain from page 753 of the 20th edition of Gray's Anatomy (1918)

  1. ^
    ISBN 978-1889325293
    .
  2. ^
    ISBN 978-0-87893-695-3
    .
  3. ^ "Divisions of the Nervous System." Neuroscience for Kids. University of Washington. http://faculty.washington.edu/chudler/nsdivide.html
  4. ^ a b Dafny, N. (1997). Anatomy of the spinal cord. http://neuroscience.uth.tmc.edu/s2/chapter03.html Archived 2011-10-08 at the Wayback Machine
  5. ^ a b c d e f g h Dlugos, C. (1999). Autonomic nervous system. http://www.smbs.buffalo.edu/ana/newpage41.htm
  6. PMID 7235870
    .
  7. ISBN 9780444519252
    .
  8. ^ "How Cells Communicate During the Fight or Flight Response." Genetic Science Learning Center, University of Utah. "How Cells Communicate During the Fight or Flight Response". Archived from the original on 2013-08-08. Retrieved 2013-10-23.
  9. ^ "The Science of Stress." Weber State University. http://faculty.weber.edu/molpin/healthclasses/1110/bookchapters/stressphysiologychapter.htm Archived 2017-11-20 at the Wayback Machine
  10. ^ Reddy, Sumathi. "Why We Sweat When We're Stressed". WSJ. Retrieved 2023-03-14.
  11. ^ Tank, P. W. (2009). Nerves of the Thoracic Region.http://anatomy.uams.edu/anatomyhtml/nerves_thorax.html
  12. ^ Harting, John. "Hypothalamus," Neuroscience Coursebook. University of Wisconsin. January 21, 2005. Web. http://www.neuroanatomy.wisc.edu/coursebook/neuro2(2).pdf
  13. PMID 1619762
    .
  14. S2CID 46267684
    .
  15. S2CID 219212717
    .
  16. S2CID 11957905
    .
  17. ^
    S2CID 29561772
    .
  18. ^ Benzel, E., Waxman, C., Stephen, G., Byrne, T. N. "Diseases of the Spine and Spinal Cord." Oxford University Press, USA, 2000.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Lateral_grey_column&oldid=1209578305"