**Question:** First change seen in acute inflammation is:

A. Increased blood flow
B. Vasodilation
C. Redness
D. Edema

**Correct Answer:**

**Core Concept:**
Acute inflammation is a defensive response of the body to eliminate the cause of injury (e.g., pathogens or damaged tissues), and to restore homeostasis. This process involves various cellular and molecular changes, including increased blood flow, vasodilation, redness, and edema.

**Why the Correct Answer is Right:**

During acute inflammation, several changes occur in the affected area. The first change that occurs is the increase in blood flow. This increased blood flow brings more oxygen and nutrients to the site of injury, allowing the immune cells to rapidly respond to eliminate the cause of inflammation and promote healing. Vasodilation (widening of blood vessels) is a mechanism that contributes to this increase in blood flow, enabling efficient delivery of essential substances to the inflamed area.

**Why Each Wrong Option is Incorrect:**

A. Increased blood flow is the primary cause of the subsequent changes. Vasodilation is one of the mechanisms that contribute to increased blood flow, but it is not the primary change itself.
B. Vasodilation is a consequence of increased blood flow, not the cause of the first change.
C. Redness is a visible sign of acute inflammation, but it is a result of increased blood flow and vasodilation, not the first change.
D. Edema occurs later in the inflammatory process, after increased blood flow and vasodilation.

**Clinical Pearl:**
Understanding the sequence of events during acute inflammation is crucial for medical students and practicing physicians alike. Acute inflammation is a critical part of the immune response and healing process, and recognizing its early changes can help in making an accurate clinical diagnosis.