Nokea
Which characteristics describe Pneumocystis jiroveci infection, an opportunistic disease that can be associated with HIV?
- A. May cause fungal meningitis
- B. Diagnosed by lymph node biopsy
- C. Pneumonia with dry, nonproductive cough
- D. Viral retinitis, stomatitis, esophagitis, gastritis, or colitis
Correct Answer: C
Rationale: Pneumocystis jiroveci pneumonia typically presents with a dry, nonproductive cough, shortness of breath, and fever.
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In the 1960s, smallpox was endemic:
- A. In many developing countries
- B. In North America
- C. In England
- D. Globally
Correct Answer: A
Rationale: The correct answer is A: In many developing countries. Smallpox was indeed endemic in many developing countries in the 1960s, causing significant morbidity and mortality. This is supported by historical records and epidemiological data from that time period. Choices B, C, and D are incorrect because smallpox was not endemic in North America, England, or globally during the 1960s. Smallpox eradication efforts led to the global eradication of the disease in 1980, but in the 1960s, it was still prevalent in many developing countries.
A cell type capable of killing virus-infected cells that provides early protection against viral infection is
- A. Eosinophils
- B. NK cells
- C. Neutrophils
- D. Mast cells
Correct Answer: B
Rationale: The correct answer is B: NK cells. NK cells are part of the innate immune system and can directly kill virus-infected cells, providing early protection against viral infections. They do not require prior exposure to the virus to initiate their killing mechanism, making them crucial for early defense. Eosinophils (A), Neutrophils (C), and Mast cells (D) are not primarily involved in killing virus-infected cells. Eosinophils are more associated with parasitic infections, Neutrophils are primarily involved in bacterial infections, and Mast cells are involved in allergic reactions.
Which statement indicates that the patient needs further instruction about application of ice to a sprain?
- A. "I know this ice will reduce the swelling."
- B. "I will keep the ice on this knee for the rest of the day."
- C. "I will use the ice as you have directed for 24 hours."
- D. "I can elevate my leg and use ice to reduce swelling."
Correct Answer: B
Rationale: The correct answer is B because keeping ice on the knee for the rest of the day can lead to skin damage or frostbite. Choice A is correct as it acknowledges the purpose of ice in reducing swelling. Choice C shows understanding of using ice as directed. Choice D indicates proper understanding of combining elevation with ice for swelling reduction.
The major role of the complement system is to work in conjunction with
- A. antibodies to lyse cells via the C8 and C9 components
- B. the major histocompatibility complex for cell recognition
- C. antibodies to opsonize cells
- D. the T-cell receptor for production of lymphokines
Correct Answer: A
Rationale: Rationale: The complement system is a group of proteins that enhance the ability of antibodies and phagocytic cells to clear pathogens. Choice A is correct because the C8 and C9 components of the complement system form the membrane attack complex which lyses cells. Choices B, C, and D are incorrect because the complement system primarily functions independently of the major histocompatibility complex, antibodies for opsonization, and T-cell receptor for lymphokine production.
What role do Toll-like receptors (TLRs) play in the immune response?
- A. They identify self-antigens
- B. They mediate phagocytosis directly
- C. They recognize pathogen-associated molecular patterns
- D. They suppress cytokine secretion
Correct Answer: C
Rationale: The correct answer is C because Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns (PAMPs) on pathogens, initiating the immune response. This recognition triggers the production of cytokines and chemokines, leading to inflammation and activation of immune cells. Choice A is incorrect because TLRs do not identify self-antigens but rather foreign antigens. Choice B is incorrect as TLRs do not directly mediate phagocytosis but rather initiate signaling pathways that lead to phagocytosis by immune cells. Choice D is incorrect because TLRs do not suppress cytokine secretion; rather, they stimulate cytokine production.