Learning Objectives
Identify the cellular morphology of the ependymal lining. Distinguish between ependymal cells and the underlying neural parenchyma. Understand the role of cilia in the movement of cerebrospinal fluid (CSF). Recognize the ventricular surface in a histological section.
Histology: The Ependymal Lining
The ventricles of the brain and the central canal of the spinal cord are lined by a specialized neuroepithelium known as ependyma.
- Cellular Structure: The lining consists of a single layer of cuboidal to columnar cells.
- Apical Specializations: These cells typically possess cilia and microvilli on their apical surface, which facilitate the circulation and absorption of CSF.
- Location: They form the interface between the ventricular space and the brain parenchyma (subependymal layer).
- Functional Note: Unlike most other epithelia, ependymal cells do not rest on a basement membrane; instead, their bases taper and interdigitate with underlying astrocytic processes.
Ependyma vs. Choroid Epithelium
| Feature | Ependymal Cells | Choroid Plexus Epithelium |
|---|---|---|
| Arrangement | Simple lining of ventricles | Folded villi over vascular stroma |
| Primary Function | CSF circulation & barrier | CSF Production |
| Junctions | Gap junctions (permeable) | Tight junctions (Blood-CSF barrier) |
Activity
