Emergency Medical Technician (EMT) Intermediate Practice Exam

What do basophils release during an allergic reaction, and what are their respective roles?

1. Histamines and cytokines to increase blood flow

2. Histamines and heparin to inhibit blood clotting

3. Histamines and eosinophils to destroy pathogens

4. Histamines and antigens to trigger an immune response

The correct answer is: Histamines and heparin to inhibit blood clotting

Basophils play a crucial role in the immune response, particularly during allergic reactions. They release substances that contribute to the inflammation and allergic response in the body. Histamines, one of the main components released by basophils, lead to increased blood flow and vascular permeability, which can result in symptoms commonly associated with allergies, such as swelling and redness. Heparin, another substance released by basophils, functions as an anticoagulant, inhibiting blood clotting. This helps maintain blood flow and prevents clot formation in areas of inflammation, allowing immune cells greater access to the affected tissues. This dual action of releasing histamines to enhance inflammatory response and heparin to facilitate smooth blood flow is critical in managing the body's reaction to allergens. Other options provided do not accurately describe the roles of the substances released by basophils during allergic reactions. For example, while eosinophils are indeed involved in allergic responses, they are not released by basophils. Furthermore, the concept of basophils releasing antigens is not correct, as antigens are typically substances that provoke an immune response rather than being released by immune cells.