ATI RN
ATI Pathophysiology Exam 1
1. A patient has been prescribed mifepristone (RU-486) to terminate a pregnancy. How does this drug achieve its therapeutic effect?
- A. By inhibiting the action of progesterone, which is necessary to maintain pregnancy.
- B. By increasing estrogen levels, which induce uterine contractions.
- C. By altering the uterine lining, preventing implantation.
- D. By stimulating uterine contractions, which expel the embryo.
Correct answer: A
Rationale: Mifepristone (RU-486) functions by inhibiting the action of progesterone, a hormone crucial for maintaining pregnancy. By blocking progesterone, mifepristone disrupts the uterine environment necessary for pregnancy continuation, ultimately leading to termination. Choice B is incorrect because mifepristone does not increase estrogen levels; instead, it acts on progesterone. Choice C is incorrect as mifepristone's mechanism does not involve altering the uterine lining to prevent implantation. Choice D is incorrect because mifepristone does not directly stimulate uterine contractions; its primary action is through progesterone inhibition.
2. In which of the following cases is dehydration more likely to occur?
- A. A 50-year-old woman who is a bodybuilder
- B. A 50-year-old man who is morbidly obese
- C. A 10-year-old child who is thin
- D. A 30-year-old with multiple sclerosis
Correct answer: B
Rationale: The correct answer is B. Morbid obesity increases the risk of dehydration due to the larger body surface area and potential for greater insensible losses. Choices A, C, and D are less likely to experience dehydration compared to a morbidly obese individual.
3. Which disorder is caused by a Staphylococcus aureus organism producing a toxin leading to exfoliation and large blister formation?
- A. Herpes simplex I virus
- B. Bullous impetigo
- C. Necrotizing fasciitis
- D. Cellulitis
Correct answer: B
Rationale: Bullous impetigo is the correct answer because it is caused by a Staphylococcus aureus toxin that leads to exfoliation and the formation of large blisters. Herpes simplex I virus (Choice A) causes cold sores and is not associated with exfoliation and blister formation. Necrotizing fasciitis (Choice C) is a severe skin infection involving the deeper layers of skin and subcutaneous tissues, typically caused by bacteria such as Streptococcus or Clostridium species, not Staphylococcus aureus. Cellulitis (Choice D) is a common bacterial skin infection, but it does not involve exfoliation and blister formation as seen in bullous impetigo.
4. A 5-year-old female takes a hike through the woods during a school field trip. Upon returning home, she hugs her father, and he later develops poison ivy. Which of the following immune reactions is he experiencing?
- A. IgE-mediated
- B. Tissue-specific
- C. Immune complex
- D. Cell-mediated
Correct answer: D
Rationale: The father's immune reaction to poison ivy is an example of cell-mediated immunity, specifically a type IV hypersensitivity reaction. In this type of reaction, sensitized T cells react to antigens, leading to inflammation and tissue damage. IgE-mediated reactions involve antibodies of the IgE class, commonly seen in allergic responses like anaphylaxis. Tissue-specific reactions target specific organs or tissues. Immune complex reactions involve immune complexes formed by antigens and antibodies that can deposit in tissues, leading to inflammation.
5. Which of the following best describes Cushing’s syndrome?
- A. Hypersecretion of growth hormone
- B. Excessive production of cortisol by the adrenal glands
- C. Insufficient production of insulin
- D. Increased levels of ACTH
Correct answer: B
Rationale: Cushing’s syndrome is characterized by the excessive production of cortisol by the adrenal glands, not growth hormone (Choice A), insulin (Choice C), or ACTH (Choice D). The increased cortisol levels lead to a variety of symptoms associated with Cushing’s syndrome.
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