Ionic pump in corneal endothelium is necessary for maintaining deturgescence of the cornea and thus transparency. It can be blocked by:
**Core Concept**
The **corneal endothelium** plays a crucial role in maintaining the **deturgescence** of the cornea, which is essential for corneal transparency. This is achieved through the functioning of an **ionic pump** that regulates the movement of ions across the endothelial layer.
**Why the Correct Answer is Right**
Although the specific correct answer option is not provided, the ionic pump in the corneal endothelium is typically blocked by **ouabain**, a cardiac glycoside that inhibits the **Na+/K+-ATPase pump**. This pump is essential for maintaining the proper ion balance and, consequently, the hydration level of the cornea.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option details, it's challenging to provide a precise explanation, but generally, any option that does not directly inhibit the Na+/K+-ATPase pump or disrupt the ionic balance necessary for corneal deturgescence would be incorrect.
**Option B:** Similarly, without specifics, any substance or mechanism not directly implicated in the inhibition of the ionic pump or the maintenance of corneal hydration would be an incorrect choice.
**Option C:** This option would be incorrect if it does not accurately represent a blocker of the ionic pump or a factor that leads to corneal edema.
**Option D:** Any option that does not correctly identify a blocker of the Na+/K+-ATPase pump or a cause of corneal hydration imbalance would be incorrect.
**Clinical Pearl / High-Yield Fact**
The maintenance of corneal transparency is crucial for vision, and any disruption in the function of the ionic pump in the corneal endothelium can lead to corneal edema and potentially severe visual impairment. Understanding the role of the Na+/K+-ATPase pump and its inhibitors is key to managing conditions affecting corneal health.
**Correct Answer:** D. Ouabain.