Emergency Medical Technician (EMT) Intermediate Practice Exam

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Prepare for your EMT Intermediate Test. Study with detailed flashcards and multiple-choice questions, each featuring hints and explanations. Ace your exam!

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What is the main role of histamines released during an allergic reaction?

Inhibit blood flow
Reduce inflammation
Increase tissue inflammation
Stimulate blood clotting

The correct answer is: Increase tissue inflammation

Histamines play a crucial role during an allergic reaction, primarily by increasing tissue inflammation. When the immune system encounters an allergen, it responds by releasing histamines from mast cells. These chemical messengers are responsible for several physiological changes. They cause blood vessels to dilate (expand) and become more permeable, allowing fluids and immune cells to move into the affected tissues. This influx results in the characteristic symptoms of an allergic reaction, such as redness, swelling, and itching. The increase in tissue inflammation serves to facilitate the body's defense mechanisms against the perceived threat posed by the allergen. While this process is essential for fighting off harmful invaders, it can lead to discomfort and symptoms associated with allergic reactions, highlighting the double-edged nature of histamine's role in immune response.