Nokea
Which of the following is a feature of an adaptive immune response
- A. Triggered within minutes/hours of antigen exposure
- B. Present in all multicellular organisms
- C. Results in the induction of memory of previously encountered antigens
- D. Always able to discriminate self from non-self in all individuals
Correct Answer: C
Rationale: The correct answer is C because an adaptive immune response induces memory of previously encountered antigens. This memory allows the immune system to respond more rapidly and effectively upon subsequent exposures to the same antigen. This feature is crucial for long-term immunity. Option A is incorrect since adaptive immune responses typically take days to develop. Option B is incorrect as not all multicellular organisms possess adaptive immunity. Option D is incorrect because immune tolerance mechanisms can sometimes fail, leading to autoimmune disorders where self is not distinguished from non-self.
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Which of the following is an important nursing intervention for HIV-positive clients?
- A. Suggesting the use of herbal medications and alternate therapies.
- B. Suggesting the use of psychostimulants such as methamphetamine.
- C. Advising client to avoid clinical drug trials.
- D. Providing referral to support groups and resources for information.
Correct Answer: D
Rationale: Providing referrals to support groups and resources helps clients manage their condition and access necessary care.
Which of the following is a safety mechanism of the complement system?
- A. Binding C5a to plasma inhibitors
- B. Activation of complement only in the absence of pathogens
- C. Covalent binding of C3b and C4b to pathogen surfaces
- D. Suppression of C1 activation by antibodies
Correct Answer: C
Rationale: Rationale for Choice C: Covalent binding of C3b and C4b to pathogen surfaces is a safety mechanism of the complement system because it helps in targeting pathogens specifically, enhancing opsonization, and preventing damage to host cells by limiting complement activation to the pathogen surface. C3b and C4b form stable covalent bonds with the pathogens, marking them for destruction by phagocytes. This mechanism ensures that complement activation is directed towards the pathogen and not host cells, thus maintaining immune homeostasis.
Summary:
A: Binding C5a to plasma inhibitors is not a safety mechanism but a regulatory mechanism in the complement system.
B: Activation of complement only in the absence of pathogens is incorrect as the complement system can be activated in response to various stimuli, not just pathogens.
D: Suppression of C1 activation by antibodies is not a safety mechanism but a regulatory mechanism involving the classical pathway of complement activation.
Human immunodeficiency virus (HIV) infects:
- A. CD4+ T cells
- B. B cells
- C. CD8+ T cells
- D. All of the above
Correct Answer: A
Rationale: The correct answer is A: CD4+ T cells. HIV primarily infects CD4+ T cells by binding to the CD4 receptor and a co-receptor, usually CCR5 or CXCR4. CD4+ T cells are crucial for coordinating the immune response. B cells (choice B) are not typically infected by HIV. CD8+ T cells (choice C) can be indirectly affected by HIV, but they are not the primary target of the virus. Therefore, the correct choice is A as it accurately reflects the primary target cells of HIV infection.
The nurse is assessing a client for signs and symptoms of systemic lupus erythematosus (SLE). Which of the following would be consistent with this disorder? (Select one that does not apply.)
- A. Discoid rash on skin exposed to sunlight
- B. Urinalysis negative for casts and protein
- C. Painful, deformed small joints
- D. Pain on inspiration
Correct Answer: A
Rationale: The correct answer is A: Discoid rash on skin exposed to sunlight. Systemic lupus erythematosus (SLE) commonly presents with a characteristic butterfly-shaped rash on the face, especially over the cheeks and nose, that worsens with sunlight exposure. The rash is not limited to skin exposed to sunlight. Choices B, C, and D are inconsistent with SLE. B: Urinalysis negative for casts and protein is not indicative of SLE, as renal involvement in SLE often presents with the presence of casts and protein in the urine. C: Painful, deformed small joints is more typical of rheumatoid arthritis, not SLE. D: Pain on inspiration is a symptom of pleurisy, which can occur in SLE but is not a defining feature.
A cell whose functions include ingesting foreign or invading cells is a (an):
- A. T cell.
- B. B cell.
- C. Macrophage.
- D. Erythrocyte.
Correct Answer: C
Rationale: Macrophages are specialized cells that engulf and digest pathogens, cellular debris, and other foreign substances. T cells and B cells play roles in adaptive immunity, while erythrocytes (red blood cells) are involved in oxygen transport.