Spinal cord

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The nervous system comprises of two subdivisions, the central nervous system and the peripheral nervous system. The central nervous system consists of the brain and the spinal cord and the peripheral nervous system involves nerves and nerve cells which lie exterior to the brain and spinal cord [1]/

Thirty-one pairs of nerves lead out of the spinal cord and provide for the skin and muscles. The damage of a spinal nerve can lead to loss of movement and are usually permanent due to the fact that nerve cells are non-renewable. Incoming sensory fibres and outgoing motor fibres split into spinal roots where the nerves attach to the spinal cord [2].

A lot of peripheral nerves interconnect with the central nervous system via the spinal cord which is protected within the bony vertebral column [3].

The role of the spinal cord is not on the organisation and protection nerves, but also to aid movement and support the body. 

Organisation of the spinal cord

Dorsal and ventral roots are arranged in pairs down the spinal cord and each spinal nerve consisting of dorsal root and ventral root axons. Spinal segments are divided into four groups: cervical, thoracic, lumbar and sacral [4].

The spinal cord is made up of an internal core of gray matter, bordered by a dense layer of white matter strips called columns. Each half of the spinal gray matter is separated into a dorsal horn and an intermediate zone and a ventral horn. The neurons receiving sensory input from primary afferents are called second-order sensory neurons and generally lie in the dorsal horns [5].

Blood Supply

The spinal cord has three sources of blood supply with three arteries; the anterior spinal artery, right posterior spinal artery and the left posterior spinal artery [6].

References

  1. Mark F. Bear, Barry W. Connors, Michael A. Paradiso (2007) Neuroscience 3rd edition, Baltimore, Lippincott Williams and Wilkins p8, p394
  2. Mark F. Bear, Barry W. Connors, Michael A. Paradiso (2007) Neuroscience 3rd edition, Baltimore, Lippincott Williams and Wilkins p394
  3. Mark F. Bear, Barry W. Connors, Michael A. Paradiso (2007) Neuroscience 3rd edition, Baltimore, Lippincott Williams and Wilkins p8, p395
  4. Mark F. Bear, Barry W. Connors, Michael A. Paradiso (2007) Neuroscience 3rd edition, Baltimore, Lippincott Williams and Wilkins p8, p395
  5. Mark F. Bear, Barry W. Connors, Michael A. Paradiso (2007) Neuroscience 3rd edition, Baltimore, Lippincott Williams and Wilkins p8, p394
  6. http://en.wikipedia.org/wiki/Spinal_cord Blood Supply
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