Nursing Elites

1. After exposure to a pathogen, the immune system develops memory. What type of immune cell is responsible for this immunological memory?

• A. B cells
• B. T cells (specifically memory T cells)
• C. Phagocytes
• D. Natural killer cells

Correct answer: A

Rationale: B cells are responsible for immunological memory. Memory B cells, a type of B cells, retain a 'memory' of specific pathogens, enabling them to rapidly produce antibodies upon re-exposure. This rapid antibody production facilitates a quicker and more effective immune response. Although memory T cells also contribute to immunological memory by mounting a swift and robust immune response upon re-exposure to the pathogen, it is primarily memory B cells that play a crucial role in producing antibodies. Phagocytes are important immune cells involved in engulfing and digesting pathogens, while natural killer cells are primarily responsible for recognizing and eliminating abnormal cells, such as virus-infected cells or tumor cells. However, when it comes to immunological memory and antibody production, B cells are key players.

2. What is the stage of mitosis during which the nuclear envelope reforms?

• A. Prophase
• B. Metaphase
• C. Telophase
• D. Cytokinesis

Correct answer: C

Rationale: During telophase, the nuclear envelope reforms around the separated sister chromatids at opposite poles of the cell. This stage marks the reversal of the processes that occurred during prophase, where the nuclear envelope breaks down. Metaphase is characterized by the alignment of chromosomes along the metaphase plate in the cell's center. Cytokinesis is the final step of cell division involving cytoplasmic division to form two daughter cells, but it does not involve the reformation of the nuclear envelope. Therefore, choice C (Telophase) is the correct answer as it specifically involves the reformation of the nuclear envelope, distinguishing it from the other stages of mitosis.

3. Through which aspect do afferent fibers enter the spinal cord?

• A. Through the anterior aspect
• B. Through the dorsal aspect
• C. Through the ventral aspect
• D. Through the lateral aspect

Correct answer: B

Rationale: Afferent fibers, responsible for carrying sensory information, enter the spinal cord through the posterior (dorsal) aspect. Specifically, they enter through the dorsal roots, located on the back (posterior) side of the spinal cord. This route allows sensory information to be transmitted to the central nervous system for processing and integration. Choices A, C, and D are incorrect because afferent fibers do not enter the spinal cord through the anterior, ventral, or lateral aspects.

4. Which part of the brain is responsible for controlling involuntary actions like breathing and heart rate?

• A. Cerebellum
• B. Medulla oblongata
• C. Cerebrum
• D. Thalamus

Correct answer: B

Rationale: The correct answer is the Medulla oblongata. This region of the brain is located in the brainstem and is responsible for controlling vital autonomic functions such as breathing, heart rate, and blood pressure. The Cerebellum (Choice A) is primarily involved in coordination and balance. The Cerebrum (Choice C) is responsible for higher brain functions like thinking and voluntary muscle movement. The Thalamus (Choice D) acts as a relay station for sensory information but is not primarily responsible for controlling involuntary actions like breathing and heart rate.

5. Which of the following cations is found at the center of a heme?

• A. Cr (III)
• B. Cu (II)
• C. Iron (II)
• D. Iron (III)

Correct answer: C

Rationale: The correct answer is Iron (II) (Fe2+), which is the cation found at the center of a heme group. Heme contains an iron (II) ion that is coordinated within the porphyrin ring structure. This iron ion is crucial for the function of heme in binding and transporting oxygen in hemoglobin and myoglobin. Choice A (Cr (III)) is incorrect as chromium is not typically found at the center of a heme group. Choice B (Cu (II)) is incorrect as copper is not the cation typically present in heme. Choice D (Iron (III)) is also incorrect as heme predominantly contains iron (II) at its center, not iron (III).

Similar Questions