The inflammatory response produced

Correct Answer: D

Rationale: The correct answer is D. The inflammatory response can be triggered by microbial-infected cells releasing cytokines, internal tissue injury leading to the release of inflammatory mediators, and the migration of erythrocytes from the spleen in response to inflammation. Therefore, all of the choices - A, B, and C - are correct in contributing to the inflammatory response. Each option plays a role in the complex cascade of events that lead to inflammation.

Correct Answer: C

Rationale: The primary function of white blood cells is to protect the body from foreign substances such as bacteria, viruses, and other pathogens. They do this by identifying and attacking these invaders to prevent infections and maintain overall health. White blood cells are a crucial part of the immune system and play a key role in defending the body against diseases. Clotting and sealing damaged blood vessels (choice A) is primarily done by platelets, not white blood cells. Transporting oxygen and carbon dioxide (choice B) is the function of red blood cells, not white blood cells. Producing hormones (choice D) is mainly performed by endocrine glands, not white blood cells.

Correct Answer: A

Rationale: The correct answer is A: Hematoma. A hematoma is an abnormal collection of blood within tissues. This occurs due to broken blood vessels and can lead to swelling and localized pain. Thrombosis (B) is the formation of a blood clot within a blood vessel, not an accumulation of blood in tissue. An embolus (C) is a blood clot that travels through the bloodstream and gets lodged in a blood vessel. Hemorrhage (D) refers to the excessive bleeding from blood vessels. In this case, the most appropriate term for an abnormal accumulation of blood in a tissue is hematoma.

Correct Answer: A

Rationale: The correct answer is A: E. coli 0157:H7. This strain of E. coli has acquired virulence factors that allow it to cause severe illness in humans, such as bloody diarrhea and kidney failure. The transformation of E. coli from a commensal to a pathogenic strain is well-documented. In contrast, choices B and C involve species that are inherently pathogenic and not commensal. Choice D is too broad and includes a wide range of bacterial species that do not necessarily originate from the normal flora. Therefore, E. coli 0157:H7 is the best example of a commensal bacterium that has turned pathogenic due to the acquisition of virulence factors.

Correct Answer: C

Rationale: The correct answer is C because NADPH oxidase is not constitutively expressed as a complex of 5 subunits in unstimulated cells. Instead, it is assembled and activated upon stimulation, such as during the respiratory burst following phagocytosis. Choice A is correct as NADPH oxidase is indeed involved in the respiratory burst. Choice B is correct as mutations in NADPH oxidase subunits lead to impaired pathogen killing and recurrent infections. Choice D is correct as NADPH oxidase controls the production of reactive oxygen species.