Final answer:
The five structures composed of white matter cells in the CNS are tracts, white columns, posterior columns, anterior columns, and lateral columns.
Step-by-step explanation:
The five structures composed of white matter cells in the CNS are:
1. **Tracts** - Bundles of axons that connect different areas of the brain.
2. **White Columns** - Longitudinal continuous bands of white matter in the spinal cord.
3. **Posterior Columns** - White matter regions between the two posterior horns of gray matter in the spinal cord.
4. **Anterior Columns** - White matter regions between the two anterior horns of gray matter in the spinal cord.
5. **Lateral Columns** - White matter regions on either side of the spinal cord, between the posterior horn and the axons of the anterior horn neurons.