Nokea
In LN naïve T cells and activated dendritic cells interact in the
- A. Subcapsular sinus
- B. Cortex
- C. Paracortex
- D. Medulla
Correct Answer: C
Rationale: The correct answer is C: Paracortex. Naïve T cells circulate through the blood and lymphatic system until they encounter antigens presented by activated dendritic cells in the paracortex of lymph nodes. The paracortex is the region where T cell activation and proliferation occur, leading to an immune response. The subcapsular sinus (A) is primarily involved in filtering lymph fluid, the cortex (B) contains B cell follicles, and the medulla (D) contains plasma cells and macrophages. Thus, the paracortex is the specific site of interaction between naïve T cells and activated dendritic cells in lymph nodes.
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A protective response to Leishmania parasites is most likely to occur when:
- A. Activated Th cells differentiate into Th1 effectors that secrete IL-4 required to induce secretion of appropriate antibody isotypes
- B. Activated Th cells differentiate into Th2 effectors that secrete IL-4 required to activate macrophages
- C. Activated Th cells differentiate into Th1 effectors that secrete IFNγ required to activate macrophages
- D. Either a Th1- or a Th2-mediated response occurs
Correct Answer: C
Rationale: The correct answer is C because in response to Leishmania parasites, the activation of Th cells into Th1 effectors that secrete IFNγ is crucial for activating macrophages to eliminate the intracellular parasites. IFNγ enhances the microbicidal activity of macrophages, helping to control the infection.
Choice A is incorrect because IL-4 is not required to induce the appropriate antibody response against Leishmania parasites.
Choice B is incorrect because Th2 effectors secreting IL-4 would not activate macrophages effectively against Leishmania, which is an intracellular pathogen.
Choice D is incorrect because in the case of Leishmania, a Th1-mediated response is most effective due to the need for macrophage activation by IFNγ.
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.
What is a compensatory mechanism for metabolic alkalosis?
- A. Shifting of bicarbonate into cells in exchange for chloride
- B. Kidney conservation of bicarbonate and excretion of hydrogen ions
- C. Deep,rapid respirations (Kussmaul respirations) to increase CO2 excretion
- D. Decreased respiratory rate and depth to retain CO2 and kidney excretion of bicarbonate
Correct Answer: D
Rationale: To compensate for metabolic alkalosis, the body decreases respiratory rate to retain CO2 and excretes bicarbonate via kidneys.
What is a defining characteristic of immunology as a scientific field?
- A. It is largely static, with few modern discoveries
- B. It is a dynamic field, continually evolving through research
- C. It exclusively studies pathogen biology
- D. It focuses solely on innate immunity
Correct Answer: B
Rationale: The correct answer is B: It is a dynamic field, continually evolving through research. Immunology is constantly evolving due to new discoveries and advancements in technology. Research in immunology leads to a deeper understanding of the immune system and its interactions with pathogens, cancer, and other diseases. This ongoing evolution is essential for the development of new treatments and vaccines.
Explanation of why other choices are incorrect:
A: It is largely static, with few modern discoveries - This is incorrect as immunology is a rapidly advancing field with numerous breakthroughs and discoveries.
C: It exclusively studies pathogen biology - This is incorrect as immunology also encompasses the study of the immune system's responses to various stimuli, not just pathogens.
D: It focuses solely on innate immunity - This is incorrect as immunology covers both innate and adaptive immunity, as well as the interactions between them.
Which of the following should a client with autoimmune disorder be advised to avoid?
- A. Rest during the periods of severe exacerbation
- B. Regular exercise during the periods of remission
- C. Being in crowds during the periods of immunosuppression
- D. Humid environment during the periods of remission
Correct Answer: C
Rationale: Clients with autoimmune disorders especially during immunosuppression should avoid crowds to reduce the risk of infections.