Nokea
Lysozyme is NOT
- A. An enzyme present in secretions and tears
- B. A type of Defensin
- C. Part of the chemical innate barriers to infection
- D. A protein capable of dissolving the cell wall of bacteria
Correct Answer: B
Rationale: The correct answer is B because lysozyme is not a type of defensin. Lysozyme is an enzyme present in secretions and tears, part of chemical innate barriers to infection, and capable of dissolving the cell wall of bacteria. Defensins are a different type of antimicrobial peptides that function by disrupting the microbial cell membrane. Therefore, B is the correct answer as it does not accurately describe lysozyme's function.
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Which of the following statement is incorrect
- A. Antigens in tissues can reach regional LN via afferent lymphatic vessels
- B. Migrating dendritic cells that have collected antigens in tissues enter the draining LN via HEV
- C. During an infection fever and other inflammatory signals induce increased blood flow to draining LN and increased chances for lymphocytes to migrate from blood into LN
- D. The thoracic duct returns most of the circulating lymphocytes back to blood
Correct Answer: B
Rationale: The correct answer is B because migrating dendritic cells do not enter the draining lymph node (LN) via high endothelial venules (HEV); instead, they enter through afferent lymphatic vessels. HEVs are specialized post-capillary venules in LN where lymphocytes enter from the bloodstream. Dendritic cells, carrying antigens from tissues, travel via afferent lymphatic vessels to reach the LN where they present antigens to lymphocytes. Option A is correct as antigens in tissues reach LN via afferent lymphatic vessels. Option C is correct as infection-induced signals can increase blood flow to LN, facilitating lymphocyte migration. Option D is incorrect because the thoracic duct returns lymph back to the bloodstream, not specifically lymphocytes.
Which of the following is a clinical feature of Grave's disease?
- A. Pulmonary fibrosis
- B. Exophthalmos and goiter
- C. Skin vasculitis
- D. Eczematous reaction
Correct Answer: B
Rationale: The correct answer is B: Exophthalmos and goiter. In Grave's disease, there is an overproduction of thyroid hormones leading to hyperthyroidism. Exophthalmos (bulging eyes) and goiter (enlarged thyroid gland) are classic clinical features due to autoimmune stimulation of thyroid-stimulating hormone receptors. Pulmonary fibrosis (A) is not typically associated with Grave's disease. Skin vasculitis (C) and eczematous reaction (D) are also not commonly seen in Grave's disease.
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.
When the clinic nurse starts to take the "air cast" off the grade 2 sprain, the patient asks why it is being removed since he still has pain. Which explanation is best?
- A. "Long-term immobilization can interfere with adequate circulation."
- B. "Long-term immobilization may increase long-term edema."
- C. "Long-term immobilization can cause permanent disability."
- D. "This cast will be replaced with a heavier cast."
Correct Answer: C
Rationale: The correct answer is C because long-term immobilization can indeed cause permanent disability in the case of a grade 2 sprain. Prolonged immobilization can lead to muscle atrophy, joint stiffness, and decreased range of motion, which can result in long-term disability. Choice A is incorrect because adequate circulation is more related to prolonged immobilization, not short-term removal for evaluation. Choice B is incorrect as edema is a short-term concern and not a direct result of long-term immobilization. Choice D is incorrect as there is no indication that a heavier cast will be used.
Cells involved in allergic reactions include
- A. Mast cells
- B. Eosinophils
- C. Basophils
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Mast cells, eosinophils, and basophils are all involved in allergic reactions. Mast cells release histamine, leading to inflammation. Eosinophils are involved in allergic responses and parasitic infections. Basophils release histamine and other inflammatory mediators. Therefore, all three cell types play a crucial role in allergic reactions. Choices A, B, and C alone are incorrect because each cell type individually participates in allergic reactions.