L1.2.2.2: White Matter

• WHITE MATTER OF THE SPINAL CORD

  ● Composed of myelinated fiber tracts

  ○ Some are running to higher centers

  ○ Some are traveling from the brain to the cord

  ○ Some are conducting impulses from one side of the spinal cord to the other
• WHITE MATTER OF THE SPINAL CORD

  ● Sensory (afferent) tracts — conduct impulses toward the brain ● Motor (efferent) tracts — carry impulses from the brain to skeletal
• WHITE MATTER OF THE SPINAL CORD

  ● Divided into 3 REGIONS because of the irregular shape of gray matter

  ○ DORSAL COLUMN

  ■ All tracts are ascending, carrying sensory input to the brain

  ○ LATERAL COLUMN

  ■ Contain both ascending and descending motor tracts

  ○ VENTRAL COLUMN

  ■ Also contain both ascending and descending motor tracts
• WHITE MATTER OF THE SPINAL CORD

  Spastic paralysis

  - Result of transected (cut crosswise) or crushed spinal cord

  - The affected muscles stay healthy because they are still stimulated by spinal reflex arcs and movement of these muscles still occur

  - However, movements are involuntary and not controllable

  - Quadriplegic: spinal injury occurs high in the cord so all 4 limbs are affected

  - Paraplegic: only the legs are paralyzed