Nokea
What is a typical time frame for Type IV hypersensitivity reactions to develop?
- A. Within minutes
- B. 1-3 hours
- C. 24-72 hours
- D. 5-7 days
Correct Answer: C
Rationale: The correct answer is C (24-72 hours) for Type IV hypersensitivity reactions to develop. This type of reaction involves T cell-mediated immune responses, which take time to develop. Initially, sensitization occurs, followed by activation of memory T cells upon re-exposure to the antigen. This process typically takes 24-72 hours to manifest clinically. Choices A (Within minutes), B (1-3 hours), and D (5-7 days) are incorrect because Type IV reactions do not exhibit immediate responses like Type I hypersensitivity reactions (Choice A), nor do they typically take as long as 5-7 days to develop (Choice D). The time frame of 1-3 hours (Choice B) is too short for the characteristic delayed hypersensitivity reaction seen in Type IV responses.
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The nurse has administered prescribed allergen injections twice a week for several weeks to an individual with a bee sting allergy. The patient misses three appointments. What action should the nurse take on the patient's next visit?
- A. Consult physician to confirm the dosage to be given.
- B. Administer the same dosage as was given at the last visit.
- C. Administer the dosage as originally prescribed for that visit.
- D. Tell the patient that the entire immunotherapy schedule needs to be restarted.
Correct Answer: A
Rationale: The correct answer is A: Consult physician to confirm the dosage to be given. The nurse should consult the physician because missing three appointments may affect the patient's progress and tolerance to the allergen injections. The physician needs to reassess the situation and determine the appropriate action, which may involve adjusting the dosage or reevaluating the treatment plan. This ensures patient safety and effectiveness of the treatment.
Summary:
B: Administering the same dosage as the last visit may not be appropriate without physician consultation.
C: Administering the dosage as originally prescribed may not account for any changes in the patient's condition.
D: Restarting the entire immunotherapy schedule is an extreme measure and should only be considered after consultation with the physician.
Why did Barry Marshall drink a pure culture of Helicobacter pylori?
- A. To demonstrate the H. pylori is the cause of gastric cancer
- B. To demonstrate an association between H. pylori infection and gastric ulcers
- C. To demonstrate that gastric ulcers are caused by stress rather than bacterial
- D. A and B are both correct
Correct Answer: B
Rationale: Barry Marshall drank a pure culture of H. pylori to demonstrate an association between H. pylori infection and gastric ulcers. This is because he wanted to prove the theory that the bacteria is a primary cause of stomach ulcers, contradicting the prevailing belief at the time. Choice A is incorrect because the direct link between H. pylori and gastric cancer was not the primary focus of his experiment. Choice C is incorrect as his goal was to show the bacterial link to ulcers, not to disprove stress as a factor. Choice D is incorrect because only choice B accurately reflects his intended purpose.
Which T lymphocytes are involved in direct attack and destruction of foreign pathogens?
- A. Dendritic cells
- B. Natural killer cells
- C. T helper (CD4) cells
- D. T cytotoxic (CD8) cells
Correct Answer: D
Rationale: T cytotoxic (CD8) cells directly attack and destroy infected or abnormal cells, making them crucial for eliminating pathogens.
What is the primary advantage of the memory function in adaptive immunity?
- A. Rapid and stronger responses to previously encountered antigens
- B. Direct killing of pathogens without prior activation
- C. Enhanced cytokine secretion
- D. Resistance to all infections without exposure
Correct Answer: A
Rationale: The correct answer is A because memory function in adaptive immunity allows for rapid and stronger responses to previously encountered antigens. This is achieved through the presence of memory cells, such as memory B and T cells, which can quickly recognize and respond to specific pathogens upon re-exposure. This leads to a faster and more efficient immune response, providing better protection against future infections.
Choice B is incorrect because direct killing of pathogens without prior activation is a function of innate immunity, not adaptive immunity. Choice C is incorrect as enhanced cytokine secretion is not the primary advantage of memory function. Choice D is incorrect because while memory function provides protection against previously encountered antigens, it does not confer resistance to all infections without exposure.
What is the function of IgA?
- A. Allergy mediation
- B. Placental transfer
- C. Mucosal immunity
- D. Primary response
Correct Answer: C
Rationale: The correct answer is C: Mucosal immunity. IgA plays a crucial role in protecting mucosal surfaces, such as the lining of the gut and respiratory tract, from pathogens. It helps prevent infections by neutralizing and blocking the entry of harmful substances. IgA is not involved in allergy mediation (choice A), placental transfer (choice B), or primary response (choice D), as those functions are typically associated with other types of antibodies. IgA's specificity for mucosal surfaces makes it uniquely suited for providing defense at these vulnerable sites.