ATI Pathophysiology Exam 2

Correct Answer: A

Rationale: Vascular spasm is the initial step in hemostasis, where blood vessels constrict to reduce blood flow to the injured area. This constriction helps limit blood loss until further steps like platelet plug formation and coagulation can take place. Platelet plug formation and coagulation occur after the vascular spasm, making them incorrect choices. Dissolution of the clot happens much later in the healing process, after the injury has sufficiently healed.

Correct Answer: D

Rationale: Atherosclerotic plaques form in the body due to injury to the endothelium of the coronary arteries. When the endothelium is damaged, it triggers an inflammatory response that leads to the accumulation of fats, cholesterol, and other substances, forming plaques. These plaques can narrow the arteries, reducing blood flow and potentially leading to serious complications like heart attacks or strokes. Poor dietary habits (choice A) can contribute to the development of atherosclerosis by promoting the buildup of plaque-forming substances in the blood, but the direct cause is the injury to the endothelium. Administration of statin medication (choice B) is actually a treatment for high cholesterol and aims to reduce the risk of plaque formation. Interruption of blood flow to the brain (choice C) is more related to conditions like ischemic stroke rather than the primary cause of atherosclerotic plaque formation.

Correct Answer: A

Rationale: The correct answer is Clarithromycin. Clarithromycin is one of the recommended medications for treating Mycobacterium avium complex (MAC) infections in patients with HIV. It is a macrolide antibiotic that is effective against MAC. Isoniazid (INH) is used to treat tuberculosis, not MAC. Rifabutin is another medication used in the treatment of MAC infections, but clarithromycin is preferred as a first-line agent. Azithromycin is also used in the treatment of MAC infections; however, clarithromycin is more commonly recommended due to its efficacy and safety profile.

Correct Answer: A

Rationale: Vascular spasm is the initial step in hemostasis, where blood vessels constrict to reduce blood flow to the injured area. This constriction helps limit blood loss until further steps like platelet plug formation and coagulation can take place. Platelet plug formation and coagulation occur after the vascular spasm, making them incorrect choices. Dissolution of the clot happens much later in the healing process, after the injury has sufficiently healed.

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.