Learning Objectives
Identify the histological components of the choroid plexus. Understand the primary function of the choroid epithelium in CSF production. Distinguish between ependymal cells and choroid epithelial cells. Recognize the vascular stroma that provides the filtrate for cerebrospinal fluid.
Normal Histology: Choroid Plexus
The choroid plexus is a specialized structure found within the brain’s ventricles. It is the primary site for the formation of cerebrospinal fluid (CSF).
- Choroid Epithelium: A single layer of cuboidal to columnar epithelial cells. These cells possess microvilli and are joined by tight junctions, forming part of the blood-CSF barrier.
- Vascular Stroma: Located at the core of the choroid villi. It contains prominent, fenestrated blood vessels. This high permeability allows plasma to be filtered out of the blood so the epithelium can process it into CSF.
- Ependymal Lining: Visible at the periphery (often at the left of the section). These are the ciliated simple cuboidal cells that line the entire ventricular system and the central canal of the spinal cord.
Functional Correlation Table
| Structure | Primary Function | Clinical Pearl |
|---|---|---|
| Choroid Epithelium | Active secretion of CSF | Site of Choroid Plexus Papilloma |
| Fenestrated Capillaries | Plasma filtration | Lacks the standard blood-brain barrier |
| Ependymal Cells | CSF circulation/ventricular lining | Target of certain viral infections (e.g., CMV) |
