Nokea
Which pairing of immune response type and immune response feature is not correct?
- A. Innate: Acts rapidly
- B. Adaptive: Results in memory
- C. Innate: Mediated by lymphocytes
- D. Adaptive: Can distinguish between specific pathogens
Correct Answer: C
Rationale: The correct answer is C because innate immune response is not mediated by lymphocytes. Innate response involves physical barriers, such as skin and mucous membranes, and cells like macrophages and neutrophils. Lymphocytes are part of the adaptive immune response, which is characterized by specificity and memory. Choice A is correct as the innate response acts rapidly due to pre-existing mechanisms. Choice B is correct as adaptive response results in memory cells for quicker response upon re-exposure. Choice D is correct as adaptive response can recognize and respond to specific pathogens through antigen recognition.
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A patient with wheezing and coughing caused by an allergic reaction to penicillin is admitted to the emergency department (ED). Which of these medications do you anticipate administering first?
- A. methylprednisolone (Solu-Medrol) 100 mg IV
- B. cromolyn sodium (Intal) 20 mg per nebulizer
- C. albuterol (Proventil) 0.5 mL per nebulizer
- D. aminophylline 500 mg IV over 20 minutes
Correct Answer: C
Rationale: Albuterol is a bronchodilator that acts quickly to relieve wheezing and coughing caused by bronchospasm. It is the first-line treatment for acute allergic reactions affecting the airways. The other medications may be used as adjuncts but are not as immediately effective in relieving bronchospasm.
The MMR (Measles, MUMPs, Rubella) vaccine has been the object of controversy after a report (lately declared fraudulent) of an association with development of:
- A. Multiple sclerosis
- B. Autism
- C. Encephalitis
- D. Epilepsy
Correct Answer: B
Rationale: The correct answer is B: Autism. The controversy surrounding the MMR vaccine and autism emerged from a fraudulent report that falsely claimed a link between the two. Numerous scientific studies have since debunked this association, confirming the safety of the MMR vaccine. Autism is a neurodevelopmental disorder with a complex etiology, involving genetic and environmental factors, but not vaccines. Choices A, C, and D are incorrect as there is no proven causal link between the MMR vaccine and multiple sclerosis, encephalitis, or epilepsy.
What is a characteristic disease associated with Type III hypersensitivity?
- A. Grave's disease
- B. Goodpasture's syndrome
- C. Systemic lupus erythematosus (SLE)
- D. Contact dermatitis
Correct Answer: C
Rationale: The correct answer is C: Systemic lupus erythematosus (SLE). In Type III hypersensitivity, immune complexes form and deposit in tissues, leading to inflammation and tissue damage. SLE is a classic example of a Type III hypersensitivity reaction where these immune complexes deposit in various organs causing systemic inflammation and damage. Graves's disease (A) is an example of Type II hypersensitivity, where autoantibodies target cell-surface receptors. Goodpasture's syndrome (B) is a Type II hypersensitivity disease affecting the kidneys and lungs. Contact dermatitis (D) is a Type IV hypersensitivity reaction mediated by T cells, not involving immune complexes. Therefore, the correct answer is C as it aligns with the characteristic disease associated with Type III hypersensitivity.
A major antibody-mediated mechanism of defense against parasitic worms involves:
- A. Neutrophil degranulation
- B. Opsonization
- C. Triggering of physiological responses (such as coughing) that expel the worm
- D. Neutralization by IgE along the mucosal surface of the gut
Correct Answer: D
Rationale: The correct answer is D because neutralization by IgE along the mucosal surface of the gut is a major antibody-mediated mechanism against parasitic worms. IgE binds to antigens on the worm's surface, leading to the release of histamine and other mediators that help expel the worm. Neutrophil degranulation (A) is more associated with bacterial infections, opsonization (B) is mainly for phagocytosis of pathogens, and triggering physiological responses (C) is not a direct antibody-mediated defense against parasitic worms.
Which of the following is a feature of antigen recognition by B cells?
- A. Their antigen receptors are never secreted
- B. Their antigen receptors recognize a fragment of protein in combination with an MHC molecule
- C. Their receptors each have two identical antigen binding sites
- D. They recognize pattern associated molecular structures (PAMPs) that are unique to a particular pathogen
Correct Answer: C
Rationale: The correct answer is C because B cell receptors, known as antibodies, are Y-shaped proteins with two identical antigen-binding sites. This feature allows B cells to bind to specific antigens with high specificity. Each B cell receptor can bind to a unique antigen, leading to the initiation of an immune response.
Choice A is incorrect because B cell receptors can be secreted as antibodies to target antigens outside the cell.
Choice B is incorrect because B cell receptors recognize antigens directly, not in combination with MHC molecules.
Choice D is incorrect because B cells primarily recognize specific antigens rather than general PAMPs associated with pathogens.