Nokea
According to the hygiene hypothesis, which of the following factors protect us from developing immune diseases?
- A. Small family size
- B. Good sanitation
- C. Low antibiotic use
- D. Living in "westernized" countries
Correct Answer: C
Rationale: The correct answer is C: Low antibiotic use. The hygiene hypothesis suggests that reduced exposure to infections, which can happen with low antibiotic use, can lead to an increased risk of immune diseases. Antibiotics can disrupt the balance of gut microbiota, which plays a crucial role in immune system development. A: Small family size may not necessarily protect against immune diseases as it does not directly relate to exposure to infections. B: Good sanitation can reduce the spread of infections but may not necessarily protect against immune diseases. D: Living in "westernized" countries is a broad factor and does not directly address the impact of low antibiotic use on immune diseases.
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What is the main limitation of innate immunity compared to adaptive immunity?
- A. It cannot produce cytokines
- B. It lacks memory and specificity
- C. It does not include physical barriers
- D. It cannot activate complement
Correct Answer: B
Rationale: The main limitation of innate immunity compared to adaptive immunity is that innate immunity lacks memory and specificity. This means that innate immune responses do not improve upon repeated exposure to the same pathogen and cannot target specific antigens efficiently. Adaptive immunity, on the other hand, can remember previous encounters with pathogens and mount targeted responses. Choices A, C, and D are incorrect because innate immunity can produce cytokines, includes physical barriers like skin and mucous membranes, and can activate complement as part of its defense mechanisms.
What is the primary role of Helper T cells in the immune response?
- A. Killing infected host cells
- B. Producing antibodies
- C. Secreting cytokines to activate other immune cells
- D. Suppressing immune responses
Correct Answer: C
Rationale: Helper T cells primarily secrete cytokines to activate other immune cells. This is crucial for coordinating and amplifying the immune response. They do not kill infected host cells (A), as that is the role of cytotoxic T cells. Producing antibodies (B) is the function of B cells. Suppressing immune responses (D) is the role of regulatory T cells, not Helper T cells.
What is the primary characteristic of a secondary immune response?
- A. It is slower and less specific
- B. It is faster, stronger, and more specific
- C. It produces only IgM antibodies
- D. It does not involve memory cells
Correct Answer: B
Rationale: The primary characteristic of a secondary immune response is that it is faster, stronger, and more specific. This is because memory cells generated during the primary response allow for a quicker and more efficient recognition and response to the same antigen upon re-exposure. This results in a faster production of antibodies, a stronger immune response, and increased specificity. Choice A is incorrect as secondary responses are actually faster and more specific. Choice C is incorrect as secondary responses can produce IgG antibodies in addition to IgM. Choice D is incorrect because memory cells are essential for secondary immune responses.
The new parents of an infant born with Down syndrome ask the nurse what happened to cause the chromosomal abnormality. What is the best response by the nurse?
- A. During cell division of the reproductive cells there is an error causing an abnormal number of chromosomes.
- B. A mutation in one of the chromosomes created an autosomal recessive gene that is expressed as Down syndrome.
- C. An abnormal gene on one of the two chromosomes was transferred to the fetus, causing an abnormal chromosome.
- D. A process of translocation caused the exchange of genetic material between the two chromosomes in the cell, resulting in abnormal chromosomes.
Correct Answer: A
Rationale: Down syndrome is primarily caused by nondisjunction during meiosis, leading to an extra copy of chromosome 21.
The nurse is reinforcing teaching to a person who has tested positive for HIV. Which test should the nurse explain is done to confirm the diagnosis of HIV?
- A. Western blot
- B. Rheumatoid factor
- C. Antinuclear antibodies
- D. Immunoglobulin assay
Correct Answer: A
Rationale: The correct answer is A: Western blot. This test is used to confirm the diagnosis of HIV by detecting specific antibodies produced in response to the virus. It is considered the gold standard for confirming HIV infection due to its high specificity and sensitivity. The other choices (B, C, D) are not used to diagnose HIV. Rheumatoid factor and antinuclear antibodies are tests for autoimmune conditions, while immunoglobulin assay measures levels of antibodies in the blood, not specific to HIV.