Spinal Cord and Spinal Nerves

• The external anatomy of the spinal cord starts at foramen magnum (big hole at the base of the skull) and ends at inferior border of 1st lumbar vertebra.
• H's are within a sac, made of meninges that fits into the spinal cavities within the vertebrae.
• Dorsal is back and Ventral is front.
• Label where

  A) dorsal

  B) spinal canal

  C) ventral

  D) spinal cord

  E) meninges

  F) spinal cord

  
• The spinal cavity within the vertebrae extends all the way to the Coccygeal vertebrae.
• Label spinal cord

  A) cervical

  B) thoracic

  C) vertebrae

  D) lumbar

  E) saccral

  F) coccygeal

  
• The spinal cord has 31 segments, 1 pair each side. the cervical has 8 pairs, thoracic has 12, lumbar with 5, sacral with 5 and coccygeal with 1.
• The spinal nerves exit the vertebral column at the level appropriate to their origin.
• Non neuron structures

  The spinal cord extends within a meningal sac filled with cerebrospinal fluid. The end is a tapered cone called conus medularis and the filum terminale extends from conus medularis to the end of the spinal cavity.
• Conus medularis is a none-neural tissue and it is the attachment point for filum terminale.
• Filum Terminale anchors the spinal cord and it is fiborus, non-neural tissue.
• A large collection of lung nerves inferior to the end of the spinal cord is the Cauda Equina (horse tail).
• The internal anatomy of the spinal cord

  A) Posterior median sulcus

  B) sulcus

  C) fissure

  D) central canal

  E) anterior median fissure

  F) grey matter (cell bodies)

  G) white matter (axons)

  H) CNS

  I) PNS

  
• Grey matter are 4 wings containing motor neurons. the back horns contain sensory neurons, which carry sensory info.
• White matter is the spinal cord, which is surrounded by column of white matter containing axons.
• The white matter containing axons allows different parts of the spinal cord to communicate slowly, with signals passing upwards and downwards.
• Label 2 internal anatomy

  A) dorsal horns (cell bodies)

  B) lateral horn (cell bodies)

  C) ventral horn (cell bodies)

  D) dorsal column (axons)

  E) lateral column (axons)

  F) ventral column (axons)

  
• The lateral column axons that travel from cerebral cortex to contact spinal motor neurons.
• Label 3

  A) dorsal root ganglion (cell bodies)

  B) spinal nerve

  C) dorsal nerve root (axons)

  D) ventral nerve root (axons)

  
• The dorsal rot ganglion known as first-order neurons are important centres of communication between PNS and CNS.
• The flow of efferent information (out of spinal cord through ventral roots is the motor commands to effectors in the cell body.
• Sensory (afferent) is from PNS into CNS from dorsal root ganglion cell bodies and dorsal nerve root axons.
• If there was damage to the ventral horn, there would be no command to the skeletal muscle.
• Flow of afferent information into spinal cord, the cell bodies of sensory neurons are doral root ganglion. The input zone in the body associates with receptors for sensory stimulus. The output zone enters the spinal cord through dorsal roots.
• Label body

  A) spinal cord

  B) dorsal nerve roots

  C) dorsal root ganglions

  D) spinal nerve

  
• Neural information enters and exits the spinal cord through afferent and efferent passageways. Dorsal nerve roots are afferent info, ventral nerve roots are efferent info and the spinal nerve is both.
• How neural information travels in spinal nerves between body and the CNS. Sensory info travels to the spinal cord or brain, decisions are made, and then commands are sent back out to make things happen in your body.