ATI Pathophysiology Exam 2

Correct Answer: B

Rationale: After exposure to a specific antigen, B cells undergo differentiation into plasma cells. Plasma cells are responsible for producing antibodies in response to the antigen. Choice A ('B cytotoxic cells') is incorrect because B cells do not differentiate into cytotoxic cells; cytotoxic cells are typically associated with T cells. Choice C ('Bursal cells') is incorrect as bursal cells are specific to birds and not relevant to human immune responses. Choice D ('Clonal equivalents') is incorrect as it does not describe the differentiation process of B cells exposed to antigens.

Correct Answer: C

Rationale: The correct answer is C: PH 7.40, PaCO2 40 mm Hg, PaO2 90 mm Hg, HCO3 24 mEq/L. These values represent a balanced state for arterial blood gas. Choice A has lower than normal PH and HCO3 levels and higher PaCO2 and lower PaO2 levels. Choice B has higher than normal PH and HCO3 levels, lower PaCO2, and a normal PaO2 level. Choice D has a significantly lower PH and PaO2 level, normal HCO3 level, and low PaCO2 level, indicating an acidic state with impaired oxygenation.

Correct Answer: B

Rationale: Giardiasis symptoms typically develop 3 to 5 days after ingestion of the cysts. This timeframe aligns with the incubation period of the Giardia parasite. Choice A (12 to 24 hours) is too short for giardiasis to manifest. Choice C (1 to 2 weeks) and choice D (2 to 3 months) represent durations that are not consistent with the usual onset of symptoms in giardiasis.

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.

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.