Nokea
What is the main role of neutrophils in the immune response?
- A. Producing antibodies
- B. Engulfing and destroying pathogens
- C. Activating lymphocytes
- D. Synthesizing cytokines
Correct Answer: B
Rationale: Neutrophils play a crucial role in the immune response by engulfing and destroying pathogens through a process called phagocytosis. This is essential for eliminating harmful invaders from the body. Neutrophils do not produce antibodies (choice A), activate lymphocytes (choice C), or synthesize cytokines (choice D), which are functions typically carried out by other immune cells like B cells and macrophages. Therefore, the correct answer is B as it directly aligns with the primary function of neutrophils in the immune response, which is to combat infections by destroying pathogens.
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Which of the following is NOT part of innate immunity?
- A. Cytokine secretion
- B. Natural killer (NK) cell activity
- C. B cell antibody production
- D. Phagocytosis by macrophages
Correct Answer: C
Rationale: Answer C is correct because B cell antibody production is part of adaptive immunity, not innate immunity. Innate immunity is the body's first line of defense and includes mechanisms like cytokine secretion, NK cell activity, and phagocytosis by macrophages. B cells are part of the adaptive immune response, producing antibodies specific to pathogens upon exposure. This distinction is crucial in understanding the different roles innate and adaptive immunity play in protecting the body.
Which of the following statements is incorrect about allergic reactions?
- A. They always require a sensitization step during which specific IgE are secreted
- B. Allergens causing hay fever are usually inhaled
- C. Food allergy can cause hives
- D. The current guidelines for preventing peanut allergy in infants is complete avoidance of peanuts and peanut-related products until at least six months of age
Correct Answer: D
Rationale: The correct answer is D because current guidelines actually recommend early introduction of peanuts to prevent peanut allergies, not complete avoidance. This is based on research showing early introduction can reduce the risk of developing peanut allergies. Choice A is correct as sensitization is a key step in allergic reactions. Choice B is correct as inhaled allergens can cause hay fever. Choice C is correct as food allergies can indeed manifest as hives.
A patient comes to the clinic and requests testing for HIV infection. Before administering testing, what is most important for the nurse to do?
- A. Ask the patient to identify all sexual partners
- B. Determine when the patient thinks exposure to HIV occurred
- C. Explain that all test results must be repeated at least twice to be valid
- D. Discuss prevention practices to prevent transmission of the HIV to others
Correct Answer: D
Rationale: Prevention education is crucial to reduce further transmission risks while awaiting test results.
Protective immunity against Leishmania is best in individuals that make a:
- A. Strong antibody response
- B. Response that activates macrophages
- C. Response that activates mast cells
- D. Strong anti-bacterial response
Correct Answer: B
Rationale: The correct answer is B: Response that activates macrophages. Macrophages play a crucial role in controlling Leishmania infection by phagocytizing the parasites. Activating macrophages enhances their ability to kill the intracellular parasites, leading to effective immunity. Antibodies (choice A) are not as effective against intracellular pathogens like Leishmania. Mast cells (choice C) are primarily involved in allergic reactions, not protective immunity against parasites. Anti-bacterial response (choice D) is not directly relevant to combating Leishmania, an intracellular parasite.
Which of the following are not found in Cyanobacteria?
- A. thylakoids
- B. gas vesicles
- C. chloroplasts
- D. heterocysts
Correct Answer: C
Rationale: The correct answer is C: chloroplasts. Cyanobacteria do not have chloroplasts because they are prokaryotic organisms and do not possess membrane-bound organelles like chloroplasts found in eukaryotic cells. Instead, they perform photosynthesis using thylakoids, which are membrane-bound compartments where photosynthesis occurs. Gas vesicles are also present in cyanobacteria and help regulate their buoyancy. Heterocysts are specialized cells that aid in nitrogen fixation, a process that allows cyanobacteria to convert atmospheric nitrogen into a form that can be used by the organism. Therefore, the absence of chloroplasts in cyanobacteria makes choice C the correct answer.