ATI Pathophysiology Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

During anaphylaxis, a severe and potentially life-threatening allergic reaction, several physiological changes occur that are critical to understand. The correct answer highlights the key features of this response: vasodilation, bronchoconstriction, and increased vascular permeability.

Vasodilation occurs due to the release of mediators such as histamine from mast cells and basophils. This leads to the widening of blood vessels, resulting in lowered blood pressure and potentially causing shock. The inflammatory response also contributes to this vasodilation.

Bronchoconstriction is another crucial change that happens during anaphylaxis. The release of substances like leukotrienes causes the smooth muscles of the bronchi to contract, which can lead to significant respiratory distress, making it difficult for the individual to breathe.

Increased vascular permeability, also a result of histamine, allows fluid and proteins to leak into the surrounding tissues. This can contribute to swelling (edema) and further decreases blood volume, exacerbating the drop in blood pressure and complicating the shock response.

Understanding these physiological changes is essential for recognizing the severity of anaphylaxis and the necessary medical interventions, such as the administration of epinephrine, which counteracts these effects. The other options do not encompass the full