Nokea
What is NOT true about Shigella?
- A. Causes a form of bloody diarrhea
- B. It is a motile species possessing a flagellum
- C. It exploits specialized intestinal cells, called M cells, to infect the host
- D. It can travel from cell to cell, propelled by actin comets
Correct Answer: B
Rationale: The correct answer is B because Shigella is a non-motile species and does not possess a flagellum. Shigella relies on non-flagellar mechanisms for its movement within host cells. Choice A is true as Shigella causes bloody diarrhea. Choice C is also true as Shigella exploits M cells to infect the host. Choice D is true as Shigella can move from cell to cell using actin comets. In summary, choice B is incorrect because Shigella does not have a flagellum, while choices A, C, and D are all true characteristics of Shigella.
You may also like to solve these questions
What describes a primary use of biologic therapy in cancer treatment?
- A. Protect normal,rapidly reproducing cells of the gastrointestinal system from damage during chemotherapy
- B. Prevent the fatigue associated with chemotherapy and high-dose radiation as seen with bone marrow depression
- C. Enhance or supplement the effects of the host’s immune responses to tumor cells that produce flu-like symptoms
- D. Depress the immune system and circulating lymphocytes as well as increase a sense of well-being by replacing central nervous system deficits
Correct Answer: C
Rationale: Biologic therapy enhances the immune response against tumor cells, often causing flu-like symptoms.
Which of the following is NOT a function of the immune system?
- A. Promoting wound healing
- B. Fighting cancer
- C. Increasing pathogen reproduction
- D. Eliminating cell debris
Correct Answer: C
Rationale: The correct answer is C: Increasing pathogen reproduction. The immune system's main function is to protect the body from pathogens and foreign invaders, not to promote their reproduction. A: Promoting wound healing is correct as the immune system helps in tissue repair. B: Fighting cancer is correct as the immune system plays a role in recognizing and destroying cancerous cells. D: Eliminating cell debris is correct as the immune system helps in clearing out dead or damaged cells to maintain tissue health.
Why is Edward Jenner's experiment on a young boy considered a scientific landmark?
- A. Jenner inoculated the young boy using material obtained from the scabs of a milkmaid who had suffered of a very mild form of smallpox. The boy never contracted the disease.
- B. Jenner inoculated the young boy first using material obtained from the scabs of a milkmaid who had suffered of a very mild form of smallpox; subsequently he inoculated the boy with virulent smallpox.
- C. Variolation was the crude practice of injecting smallpox in a way that would supposedly protect the recipient from getting a fatal form of the disease; Jenner instead injected the young boy with cowpox. The fact that the boy did not die proved that cowpox inoculation protects against smallpox
- D. Jenner noticed the milkmaids were protected from smallpox but were often affected by a mild disease caused by cowpox. He decided to inoculate a young boy with cowpox first and subsequently with smallpox to prove that exposing people to cowpox can make them immune from getting smallpox
Correct Answer: D
Rationale: Step 1: Jenner observed milkmaids were protected from smallpox due to prior exposure to cowpox.
Step 2: Jenner decided to inoculate a young boy with cowpox first.
Step 3: Jenner then inoculated the boy with smallpox to test immunity.
Step 4: The boy did not contract smallpox, demonstrating immunity.
Step 5: Conclusion: Jenner proved cowpox exposure can make individuals immune to smallpox.
Other choices are incorrect:
A: The boy never contracted smallpox, not just because of the mild form of smallpox in the milkmaid.
B: Inoculating with virulent smallpox first would not demonstrate cowpox immunity.
C: Jenner did not just substitute cowpox for smallpox; he specifically tested immunity by exposing the boy to both viruses.
What antibody mediates Type I hypersensitivity?
- A. IgA
- B. IgE
- C. IgG
- D. IgM
Correct Answer: B
Rationale: The correct answer is B: IgE. In Type I hypersensitivity reactions, IgE antibodies are involved. Firstly, upon initial exposure to an allergen, B cells produce IgE antibodies specific to that allergen. IgE antibodies then bind to mast cells and basophils. Upon subsequent exposure to the same allergen, it cross-links the IgE antibodies on mast cells and basophils, leading to degranulation and release of inflammatory mediators like histamine. This results in the symptoms of Type I hypersensitivity reactions.
Choice A (IgA) is incorrect because IgA is mainly involved in mucosal immunity. Choice C (IgG) is incorrect because while IgG can be involved in Type II and Type III hypersensitivity reactions, it is not the primary antibody in Type I hypersensitivity. Choice D (IgM) is incorrect because IgM is typically involved in the primary immune response, not in Type I hypersensitivity reactions.
Priority Decision: On assessment of a central venous access device (CVAD) site, the nurse observes that the transparent dressing is loose along two sides. What should the nurse do immediately?
- A. Wait and change the dressing when it is due
- B. Tape the two loose sides down and document
- C. Apply a gauze dressing over the transparent dressing and tape securely
- D. Remove the dressing and apply a new transparent dressing using sterile technique
Correct Answer: D
Rationale: Loose dressings increase infection risk; replacing the dressing with sterile technique ensures safety.