Which is the innermost layer of corneal epithelium ?
**Core Concept**
The corneal epithelium is a multilayered structure composed of stratified squamous epithelial cells, providing a protective barrier against external factors. The innermost layer is crucial for maintaining corneal transparency and facilitating nutrient and waste exchange.
**Why the Correct Answer is Right**
The innermost layer of the corneal epithelium is the **basal layer**, which is in direct contact with the underlying **Bowman's layer**. This layer consists of a single layer of cuboidal cells that are rich in **mitotic activity**, allowing for rapid regeneration and maintenance of the corneal surface. The basal layer is also where **corneal stem cells** are located, responsible for replenishing the outer layers of the epithelium.
**Why Each Wrong Option is Incorrect**
**Option A:** The **suprabasal layer** is the second layer of the corneal epithelium, where cells begin to differentiate and acquire a more squamous morphology.
**Option B:** The **wing cells** are a type of corneal epithelial cell found in the **limbal region**, but they are not the innermost layer of the corneal epithelium.
**Option C:** The **apical layer** is the outermost layer of the corneal epithelium, exposed to the external environment and subject to wear and tear.
**Clinical Pearl / High-Yield Fact**
The basal layer of the corneal epithelium is particularly susceptible to damage from **chemical burns** and **ulcers**, leading to corneal perforation if left untreated.
**Correct Answer: C. Apical layer.