Nervous system - spinal cord, Biology

SPINAL CORD (MYELON)

It is part of CNS. 45 cm long (in woman 43 cm) & weight 35 gms.

Origin from lower part of medulla oblongeta.

  • Shape -

Long cylindrical, convex dorsally and flat ventrally.

Last end part is conical i.e. conus terminalsis which in the end becomes thread like i.e. filum terminalis.

It is having branchial and lumbo sacral swelling at the point of origin of fore leg and hind leg.

  • Position - Present on dorsal side inside neural canal of vertebral column upto first lumber vertebrae.
  • Meninges - Similar to brain, epidural space also present filled with fat & connection tissue.
  • Matter - White matter is outer & grey matter is inner.
  • C.S.F.- Circulatin of CSF is posterior to anterior.
  • STRUCTURE -

Spinal cord is hollow, its lumen is central canal or neurocoel filled with C.S.F.

Canal is lined by ependyma of ependymal cells. Grey mater is butterfly or H-shaped.

In it 3 pairs cornue present, these are dorsal, ventral & lateral horns.

In white matter area closed to horn is dorsal, ventral & lateral funiculli.

Dorsal horn forms dorsal arch. Ventral horn forms ventral arch.

On dorsal side dorsal sulcus with septum is present. On ventral side ventral fissure is present.

  • FUNCTIONS -

It conducts impulses to and from the brain. It controls reflex action.

Posted Date: 10/3/2012 1:39:14 AM | Location : United States







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