Increased vascular permeability in acute inflammation is due to –
**Core Concept**
Increased vascular permeability is a key feature of acute inflammation, leading to the movement of fluid and cells from the bloodstream into the inflamed tissue. This process is mediated by various chemical mediators and cellular responses. **Vasoactive amines** and **cytokines** play a crucial role in this process.
**Why the Correct Answer is Right**
The correct answer is related to the action of **histamine** and **bradykinin**, which are released from **mast cells** and **basophils**. These chemical mediators increase vascular permeability by causing **endothelial cell contraction** and **gap formation** between them, allowing fluid and cells to leak out of the bloodstream.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it is not directly related to the increase in vascular permeability.
**Option B:** Incorrect as it is not the primary mechanism.
**Option C:** Incorrect because it is not the correct answer choice provided.
**Clinical Pearl / High-Yield Fact**
Remember that increased vascular permeability leads to **edema**, a classic sign of inflammation. This process is essential for the delivery of white blood cells to the site of injury or infection.
**Correct Answer:** D. Histamine and bradykinin