Which of the following describes the etiology of a cerebrovascular accident (CVA)?

Correct Answer: B

Rationale: The correct answer is B. A cerebrovascular accident (CVA), or stroke, is often caused by a lack of blood flow to part of the brain. This leads to damage in the brain tissue due to the deprived oxygen and nutrients. Choices A, C, and D are incorrect. A blow to the head from a hard object can cause a traumatic brain injury but is not the etiology of a CVA. Excessive exercise like running does not typically lead to a stroke. A ruptured artery in the heart may result in a heart attack, not a cerebrovascular accident.

Correct Answer: A

Rationale: The correct answer is A: 'Bronchospasm after exercise.' Exercise-induced asthma involves the narrowing of the airways (bronchospasm) triggered by physical activity. This bronchospasm leads to symptoms such as coughing, wheezing, and shortness of breath. Choices B, C, and D are incorrect because exercise-induced asthma is not primarily caused by an IgE-mediated inflammatory response to an antigen, bronchoconstriction after ingesting high-allergen foods, or increased mucus production due to a genetic mutation.

Correct Answer: C

Rationale: Corrected Rationale: Peritonitis can lead to severe complications such as sepsis and shock due to the infection spreading in the abdominal cavity. Sepsis is a systemic inflammatory response to infection, and shock is a life-threatening condition where the body's organs are not receiving enough blood flow. Choices A, B, and D are incorrect. Increased peristalsis is not a typical complication of peritonitis; dizziness and malaise, as well as nausea and vomiting, are symptoms rather than complications of the condition.

Correct Answer: A

Rationale: Polycythemia Vera, characterized by excess red blood cells, can cause tissue ischemia and necrosis due to the increased blood viscosity. This condition restricts blood flow, leading to inadequate oxygen delivery to tissues and subsequent tissue damage. Choices B, C, and D are incorrect because they are not directly associated with the pathophysiology of Polycythemia Vera.

Correct Answer: A

Rationale: Anaphylaxis is a classic example of a Type 1 hypersensitivity reaction. In Type 1 hypersensitivity, allergens trigger an immediate immune response mediated by IgE antibodies, leading to the release of histamine and other mediators. This reaction can result in symptoms ranging from mild itching and hives to severe conditions like anaphylaxis, which is a life-threatening emergency. The other options, such as indigestion (choice B), beta cell destruction (choice C), and ABO transfusion reaction (choice D), are not classified as Type 1 hypersensitivity reactions. Indigestion is typically related to gastrointestinal disturbances, beta cell destruction is associated with autoimmune conditions like type 1 diabetes, and ABO transfusion reaction involves antibodies targeting incompatible blood groups, which is a different immune mechanism compared to Type 1 hypersensitivity.