Spinal Cord Physiology

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Spinal Cord Physiology

• SC.912.L.14.28

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Essential Question

• What does the spinal cord do?

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Functions

• White matter nerve impulse conduction
• Grey matter receives and integrates incoming
  and outgoing information

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Descending Tracts

• Axons within the descending tracts control the
  smooth muscles of internal organs and the
  skeletal muscles of the arms and legs.
• Neural signals follow specific pathways. In the
  case of the descending tracts axons from the
  brain synapse with cell bodies in the spinal cord
  which then send impulses out to the rest of the
  body.

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Ascending Tracts

• Sensory signals from the skin, extrmeties and
  internal organs are carried via pahtways in the
  ascending tracts.
• Most these signals are relayed to the brain. Some
  activate reflexes which are controlled by
  interneurons in the spinal cord and are not
  addressed by the brain.

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Spinal Cord Segments

• Each spinal cord segment marks where spinal
  nerves emerge from the cord to connect with
  specific regions of the body.

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Regions of Control

• Cervical spinal nerves (C1 to C8) control signals
  to the back of the head, the neck and shoulders,
  the arms and hands, and the diaphragm.
• Thoracic spinal nerves (T1 to T12) control
  signals to the chest muscles, some muscles of the
  back, and parts of the abdomen.
• Lumbar spinal nerves (L1 to L5) control signals
  to the lower parts of the abdomen and the back,
  the buttocks, some parts of the external genital
  organs, and parts of the leg.
• Sacral spinal nerves (S1 to S5) control signals
  to the thighs and lower parts of the legs, the
  feet, most of the external genital organs, and
  the area around the anus.

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Spinal cord injury

• May be damaged by tumors, blood clots, wounds,
  trauma, or herniated disks.
• Paralysis may occur depending on the extent of
  the injury.

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