Nokea
An example of a preformed chemical barrier is:
- A. Mucus
- B. Lysozyme
- C. Tight junctions in epithelial cells
- D. Cilia in the respiratory tract
Correct Answer: B
Rationale: Step-by-step rationale:
1. Lysozyme is an enzyme that destroys bacterial cell walls.
2. This action acts as a preformed chemical barrier against pathogens.
3. Mucus (choice A) is a physical barrier, not a preformed chemical one.
4. Tight junctions (choice C) and cilia (choice D) are structural components, not chemical barriers.
Summary:
- Choice B, Lysozyme, is correct as it actively targets and destroys pathogens.
- Choices A, C, and D are incorrect as they do not directly function as preformed chemical barriers.
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Why is plasmapheresis indicated in the treatment of autoimmune disorders?
- A. Obtain plasma for analysis and evaluation of specific autoantibodies
- B. Decrease high lymphocyte levels in the blood to prevent immune responses
- C. Remove autoantibodies, antigen-antibody complexes, and inflammatory mediators of immune reactions
- D. Add monocytes to the blood to promote removal of immune complexes by the mononuclear phagocyte system
Correct Answer: C
Rationale: Plasmapheresis removes harmful autoantibodies, immune complexes, and inflammatory mediators from the bloodstream.
Select the following disorders characterized by inflammation of bronchi.
- A. Asthma
- B. Bronchitis
- C. Emphysema
- D. Tuberculosis
Correct Answer: B
Rationale: Step-by-step rationale:
1. Bronchitis is characterized by inflammation of the bronchi, leading to coughing and mucus production.
2. Asthma involves inflammation and narrowing of the airways but is not specific to bronchi.
3. Emphysema is a lung disease involving damage to the air sacs, not specifically inflammation of bronchi.
4. Tuberculosis is a bacterial infection affecting the lungs, not primarily characterized by bronchial inflammation.
Summary:
Bronchitis is the correct answer as it specifically involves inflammation of the bronchi, while asthma, emphysema, and tuberculosis do not primarily exhibit this characteristic.
What distinguishes Type V hypersensitivity from Type II?
- A. It is mediated by T cells
- B. Antibodies stimulate receptors instead of destroying them
- C. It involves immune complex formation
- D. It does not involve the immune system
Correct Answer: B
Rationale: The correct answer is B because Type V hypersensitivity involves antibodies stimulating receptors instead of destroying them. In Type II hypersensitivity, antibodies target antigens on cell surfaces, leading to cell destruction. In Type V, antibodies bind to cell receptors, causing abnormal receptor activation. Choices A, C, and D are incorrect because Type V hypersensitivity is not mediated by T cells (A), does not involve immune complex formation (C), and does involve the immune system (D). Therefore, the unique characteristic of Type V hypersensitivity is the stimulation of receptors by antibodies, making choice B the correct answer.
Concerning with NLRs, which of the following is NOT correct
- A. Are cytosolic receptors for MAMPs and DAMPs
- B. Include NOD receptors
- C. In Drosophila also important for embryonic development
- D. Similar proteins are also found in plants
Correct Answer: C
Rationale: The correct answer is C because NLRs are not important for embryonic development in Drosophila. NLRs are primarily involved in immune responses by recognizing pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) in the cytosol. Choice A is correct as NLRs are indeed cytosolic receptors for MAMPs and DAMPs. Choice B is correct as NOD receptors are a subset of NLRs. Choice D is correct as similar proteins to NLRs are also found in plants, known as NBS-LRR proteins. Therefore, the incorrect statement is C, as NLRs are not essential for embryonic development in Drosophila.
PRRs able to activate NFκB include
- A. TLR4
- B. NOD1
- C. NLRP3
- D. Both A and B
Correct Answer: D
Rationale: The correct answer is D because both TLR4 and NOD1 are pattern recognition receptors (PRRs) that can activate the NF-κB pathway. TLR4 recognizes bacterial lipopolysaccharides, while NOD1 detects bacterial peptidoglycan fragments. NLRP3, choice C, is an inflammasome receptor that activates caspase-1, not NF-κB. Therefore, choices A, B, and C are incorrect as they do not directly activate NF-κB like TLR4 and NOD1.