Nokea
Which condition is caused by a Type IV hypersensitivity reaction?
- A. Anaphylaxis
- B. Sarcoidosis
- C. Grave's disease
- D. Goodpasture's syndrome
Correct Answer: B
Rationale: The correct answer is B: Sarcoidosis. Type IV hypersensitivity reactions are mediated by T cells and are characterized by delayed onset inflammatory responses. Sarcoidosis is a granulomatous disease where T cells form granulomas in affected tissues. Anaphylaxis (A) is a Type I hypersensitivity reaction involving IgE antibodies. Grave's disease (C) is an autoimmune disorder caused by Type II hypersensitivity reaction mediated by antibodies. Goodpasture's syndrome (D) is a Type II hypersensitivity reaction involving antibodies attacking basement membranes. Therefore, the correct answer is B as it fits the characteristics of a Type IV hypersensitivity reaction.
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T regulatory cells are NOT
- A. Generated in the thymus upon expression of Foxp3
- B. Generated in the periphery in response to cytokines
- C. Able to inhibit effector T cells
- D. Able to cause immunity
Correct Answer: D
Rationale: The correct answer is D because T regulatory cells are known to suppress immune responses and promote immune tolerance, which is opposite to causing immunity. Choice A is incorrect because T regulatory cells are indeed generated in the thymus upon expression of Foxp3. Choice B is incorrect as T regulatory cells can also be generated in the periphery in response to cytokines. Choice C is incorrect as T regulatory cells are known to inhibit effector T cells to regulate immune responses.
The bacterial cytoplasmic membrane contains:
- A. ester-linked phospholipids, but no sterols
- B. ester-linked phospholipids and sterols
- C. ether-linked phospholipids, but no sterols
- D. ether-linked phospholipids, sulfolipids, and glycolipids
Correct Answer: A
Rationale: The correct answer is A because bacterial cytoplasmic membranes typically contain ester-linked phospholipids but no sterols. Ester-linked phospholipids are the main component of bacterial cell membranes, providing structure and function. Sterols, like cholesterol, are not commonly found in bacterial membranes. Choice B is incorrect because sterols are not present in bacterial membranes. Choice C is incorrect because ether-linked phospholipids are more commonly found in archaea, not bacteria. Choice D is incorrect because sulfolipids and glycolipids are not primary components of bacterial cytoplasmic membranes.
How does interferon help the body’s natural defenses?
- A. Directly attacks and destroys virus-infected cells
- B. Augments the immune response by activating phagocytes
- C. Induces production of antiviral proteins in cells that prevent viral replication
- D. Is produced by viral infected cells and prevents the transmission of the virus to adjacent cells
Correct Answer: C
Rationale: Interferons induce the production of antiviral proteins in uninfected cells, preventing viral replication and spread.
Choose the correct sequence in an allergic reaction.
- A. Allergen → mast cells → histamine → B cells → IgE antibodies
- B. Allergen → IgE antibodies → B cells → histamine → mast cells
- C. Allergen → B cells → IgE antibodies → mast cells → histamine
- D. Allergen → histamine → mast cells → IgE antibodies → B cells
Correct Answer: C
Rationale: Rationale for Answer C:
1. Allergen exposure triggers B cells to produce IgE antibodies specific to the allergen.
2. IgE antibodies bind to mast cells sensitizing them.
3. Upon re-exposure to allergen, allergen binds to IgE on mast cells.
4. This triggers release of histamine and other chemicals causing allergic symptoms.
Summary:
- Choice A: Incorrect because B cells do not produce IgE antibodies before allergen exposure.
- Choice B: Incorrect because IgE antibodies are produced by B cells, not the other way around.
- Choice D: Incorrect because histamine is released after allergen binds to IgE on sensitized mast cells.
A patient had abdominal surgery 3 months ago and calls the clinic with complaints of severe abdominal pain and cramping, vomiting, and bloating. What should the nurse most likely suspect as the cause of the patient’s problem?
- A. Infection
- B. Adhesion
- C. Contracture
- D. Evisceration
Correct Answer: B
Rationale: Postoperative adhesions can form after abdominal surgeries, causing obstruction and symptoms such as pain, cramping, vomiting, and bloating. Adhesions are bands of fibrous tissue that develop during the healing process.