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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.
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The nurse notes that a patient's eosinophil level is elevated. For which health problem should the nurse plan care for this patient?
- A. Cancer
- B. Allergic reactions
- C. Acute viral infections
- D. Autoimmune diseases
Correct Answer: B
Rationale: The elevated eosinophil level indicates an allergic reaction. Eosinophils are white blood cells involved in allergic responses. They increase in response to allergens. Allergic reactions involve the immune system's response to harmless substances, triggering the release of eosinophils. Cancer, acute viral infections, and autoimmune diseases typically do not directly cause eosinophil elevation. Therefore, the correct answer is B (Allergic reactions).
Which cell type is a sentinel in the tissues and part of the innate immune system?
- A. T lymphocytes
- B. Dendritic cells
- C. B lymphocytes
- D. Plasma cells
Correct Answer: B
Rationale: The correct answer is B: Dendritic cells. Dendritic cells are sentinel cells in tissues that detect pathogens and activate the immune response. They are crucial in initiating adaptive immune responses by presenting antigens to T cells. T lymphocytes (A) are involved in adaptive immunity, not innate immunity. B lymphocytes (C) mature into plasma cells (D) which produce antibodies, but they are not sentinel cells in tissues like dendritic cells.
Which of the following lymphoid tissues has both hematopoietic and immune functions and acts as an emergency reservoir of blood and filters the blood as well?
- A. Tonsils and adenoids
- B. Thymus gland
- C. Spleen
- D. Lymph nodes
Correct Answer: C
Rationale: The spleen has both hematopoietic and immune functions acting as a blood filter and reservoir and plays a key role in removing old or damaged red blood cells.
Tropism is a phenomenon by which
- A. plants response to stimulation
- B. reducing lateral branching
- C. Affected by the length of the day and night
- D. All above
Correct Answer: A
Rationale: The correct answer is A: plants response to stimulation. Tropism refers to the growth or movement of an organism in response to a stimulus. Plants exhibit tropisms such as phototropism (response to light) and geotropism (response to gravity). This choice accurately defines the phenomenon.
Choice B is incorrect because reducing lateral branching is not a defining characteristic of tropism.
Choice C is incorrect because the length of day and night does not directly relate to tropism.
Choice D is incorrect because not all options listed are characteristics of tropism.
What is a significant consequence of the evolutionary arms race between hosts and pathogens?
- A. Pathogens evolve slower than hosts
- B. Hosts develop epigenetic changes for immune adaptation
- C. Mutations in hosts always outpace pathogen evolution
- D. Hosts and pathogens remain static in their interactions
Correct Answer: B
Rationale: The correct answer is B because hosts developing epigenetic changes for immune adaptation is a significant consequence of the evolutionary arms race between hosts and pathogens. This adaptation allows hosts to better defend against evolving pathogens over time. This process is dynamic, as both hosts and pathogens continuously evolve in response to each other.
Choice A is incorrect because pathogens can evolve rapidly to adapt to host defenses. Choice C is incorrect because while hosts may have mutations that provide advantages, pathogens can also evolve to overcome host defenses. Choice D is incorrect as the interaction between hosts and pathogens is characterized by constant adaptation and change, not remaining static.