Nokea
Which cells play a key role in linking innate and adaptive immunity?
- A. B cells
- B. Dendritic cells
- C. Eosinophils
- D. NK cells
Correct Answer: B
Rationale: The correct answer is B: Dendritic cells. Dendritic cells are antigen-presenting cells that bridge the innate and adaptive immune responses by capturing and presenting antigens to T cells, thus initiating the adaptive immune response. They are crucial for activating T cells and initiating specific immune responses.
A: B cells are responsible for antibody production in the adaptive immune response, not for linking innate and adaptive immunity.
C: Eosinophils are primarily involved in parasitic infections and allergic reactions, not in linking innate and adaptive immunity.
D: NK cells are part of the innate immune system and are involved in detecting and killing infected cells, but they do not directly link innate and adaptive immunity.
You may also like to solve these questions
Which opportunistic disease associated with AIDS is characterized by hyperpigmented lesions of skin, lungs, and gastrointestinal (GI) tract?
- A. Kaposi sarcoma
- B. Candida albicans
- C. Herpes simplex type 1 infection
- D. Varicella-zoster virus infection
Correct Answer: A
Rationale: Kaposi sarcoma is a tumor associated with AIDS and manifests as hyperpigmented lesions on the skin, lungs, and GI tract.
Priority Decision: During care of patients, what is the most important precaution for preventing transmission of infections?
- A. Wearing face and eye protection during routine daily care of the patient
- B. Wearing nonsterile gloves when in contact with body fluids, excretions, and contaminated items
- C. Wearing a gown to protect the skin and clothing during patient care activities likely to soil clothing
- D. Hand washing after touching fluids and secretions and removing gloves, as well as between patient contacts
Correct Answer: D
Rationale: Hand hygiene remains the single most effective measure in preventing the spread of infections, even when personal protective equipment (PPE) is used.
Which of the following is not a function of the immune system?
- A. Protecting the body from foreign substances
- B. Producing hormones
- C. Repairing damaged tissues
- D. All of the above are functions of the immune system
Correct Answer: B
Rationale: The correct answer is B: Producing hormones. The immune system's main functions are to protect the body from foreign substances and repair damaged tissues. Producing hormones is not a direct function of the immune system. Hormone production is primarily regulated by the endocrine system, not the immune system. Therefore, option B is not a function of the immune system. Options A and C are incorrect as protecting the body from foreign substances and repairing damaged tissues are essential roles of the immune system. Option D is incorrect because not all functions listed are actually performed by the immune system.
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.
Which defense function is a specialty of both IgG and IgA antibody?
- A. Neonatal immunity
- B. Opsonization
- C. Antibody-mediated degranulation of mast cells
- D. Complement activation
Correct Answer: B
Rationale: The correct answer is B: Opsonization. Both IgG and IgA antibodies can participate in opsonization, which involves tagging pathogens for destruction by phagocytes. IgG and IgA have specific receptors on phagocytes that recognize the tagged pathogens, enhancing their clearance. Neonatal immunity (choice A) is primarily mediated by IgG antibodies transferred from mother to fetus. Antibody-mediated degranulation of mast cells (choice C) is mainly associated with IgE antibodies in allergic reactions. Complement activation (choice D) mainly involves IgM and IgG antibodies, leading to a cascade of reactions for pathogen elimination.