Nokea
What was Edward Jenner's major contribution to immunology?
- A. Discovering antibodies
- B. Proposing innate immunity theory
- C. Developing the smallpox vaccine
- D. Discovering the germ theory of disease
Correct Answer: C
Rationale: Edward Jenner's major contribution to immunology was developing the smallpox vaccine. He introduced the concept of vaccination by using cowpox to protect against smallpox. This marked the beginning of modern immunization. Discovering antibodies (A) and proposing innate immunity theory (B) were not directly attributed to Jenner. Discovering the germ theory of disease (D) was later proposed by Louis Pasteur and Robert Koch, not Jenner. Overall, choice C is correct as it aligns with Jenner's groundbreaking work in immunization.
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Dendritic cells play a role in:
- A. Costimulation of naïve T cells
- B. Processing of protein antigens to generate peptides
- C. Presentation of peptide-MHC complexes for recognition by T cell receptors
- D. All of the above
Correct Answer: D
Rationale: Dendritic cells play a crucial role in the immune system. Firstly, they provide costimulation to activate naïve T cells (A). Secondly, they process protein antigens into peptides for antigen presentation (B). Finally, dendritic cells present peptide-MHC complexes to T cell receptors for immune response activation (C). Therefore, the correct answer is D, as dendritic cells are involved in all these processes essential for initiating and regulating immune responses. Choices A, B, and C are incorrect as they are individual roles of dendritic cells and do not encompass the full range of functions that dendritic cells perform.
Which immune cells are primarily responsible for antibody production?
- A. Neutrophils
- B. Plasma cells (derived from B lymphocytes)
- C. Natural killer cells
- D. Macrophages
Correct Answer: B
Rationale: The correct answer is B: Plasma cells (derived from B lymphocytes). B lymphocytes are responsible for producing antibodies. When activated, B cells differentiate into plasma cells, which are specialized in secreting antibodies. Neutrophils are primarily involved in phagocytosis, not antibody production. Natural killer cells are involved in killing infected cells, not antibody production. Macrophages are phagocytic cells that present antigens to activate B lymphocytes but do not produce antibodies themselves. Therefore, the correct answer is B as plasma cells derived from B lymphocytes are primarily responsible for antibody production.
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.
Vertebrate eyes are Single-lens eyes with
- A. Light is focused by the curved cornea and lens
- B. Changing the shape of the lens focuses near and far
- C. Photoreceptor cells in the retina detect light
- D. All above
Correct Answer: D
Rationale: The correct answer is D because vertebrate eyes have single-lens eyes where light is focused by the curved cornea and lens (A), and changing the shape of the lens allows for focusing at different distances (B). Additionally, photoreceptor cells in the retina detect light (C). Therefore, all of the above statements are true, making D the correct choice. Choice A is incorrect because it does not encompass the entire process of vision in vertebrate eyes, missing the role of changing the lens shape. Choice B is incorrect as it only addresses the lens shape without mentioning the role of the cornea in focusing light. Choice C is incorrect as it only focuses on the function of photoreceptor cells in the retina without considering the lens and cornea's role in focusing light.
A 69-year-old woman asks the nurse whether it is possible to 'catch' cancer because many of her friends of the same age have been diagnosed with different kinds of cancer. In responding to the woman, the nurse understands that what factor increases the incidence of tumors in older adults?
- A. An increase in autoantibodies
- B. Decreased activity of the bone marrow
- C. Decreased differentiation of T lymphocytes
- D. Decreased size and activity of the thymus gland
Correct Answer: D
Rationale: The thymus gland shrinks with age, reducing the production of new T cells, which impairs immune surveillance and increases cancer risk.