Most metabolically active layer of Cornea is
**Core Concept**
The cornea is a complex tissue composed of multiple layers, each with distinct metabolic and functional properties. The corneal layers are responsible for maintaining the transparency, hydration, and optical clarity of the cornea.
**Why the Correct Answer is Right**
The most metabolically active layer of the cornea is the **stroma**. The stroma is the thickest layer of the cornea, accounting for approximately 90% of its thickness. It is composed of highly organized collagen fibrils, keratocytes, and a network of blood vessels. The keratocytes in the stroma are responsible for the synthesis and maintenance of the extracellular matrix, which is essential for corneal transparency and hydration. The stroma also contains a high concentration of mitochondria, which are the site of cellular respiration and energy production. This high metabolic activity is necessary to maintain the structural integrity and optical clarity of the cornea.
**Why Each Wrong Option is Incorrect**
**Option A:** The epithelium is the outermost layer of the cornea and is responsible for barrier function, sensation, and regeneration. While it has some metabolic activity, it is not as metabolically active as the stroma.
**Option B:** The endothelium is a single layer of cells on the inner surface of the cornea, responsible for maintaining corneal hydration through the pumping of excess fluid out of the stroma. While it has some metabolic activity, it is not as metabolically active as the stroma.
**Option C:** The Bowman's layer is a acellular layer of dense collagen fibrils that lies between the epithelium and the stroma. It has limited metabolic activity and is not as metabolically active as the stroma.
**Clinical Pearl / High-Yield Fact**
The corneal stroma is responsible for maintaining the transparency and hydration of the cornea, and its metabolic activity is crucial for corneal health. Damage to the stroma can lead to corneal edema, scarring, and vision loss.
**Correct Answer: C. Bowman's layer is a acellular layer of dense collagen fibrils that lies between the epithelium and the stroma.