Nursing Elites

1. What is the structure and function of elastic arteries?

• A. They are the smallest arteries and constrict and dilate frequently.
• B. They are medium-sized arteries that distribute blood to various organs.
• C. They are the largest arteries and stretch and recoil to accommodate blood pressure changes.
• D. They are thin-walled arteries that supply blood to the capillaries.

Correct answer: C

Rationale: The corrected answer is C. Elastic arteries, like the aorta, are the largest arteries in the body. They possess elastic fibers in their walls, allowing them to stretch and recoil in response to the pulsatile nature of blood flow from the heart. This elasticity helps to maintain blood pressure by absorbing the pressure waves generated by the heart's contractions and ensuring continuous blood flow to the organs. Choices A, B, and D are incorrect because elastic arteries are not the smallest arteries, do not constrict and dilate frequently, are not medium-sized arteries for distributing blood to various organs, and are not thin-walled arteries supplying blood to capillaries. Elastic arteries have a specific structure and function related to their ability to accommodate blood pressure changes due to their elastic properties, which is essential for the cardiovascular system's proper functioning.

2. Which vitamin plays a vital role in immune function?

• A. Vitamin A
• B. Vitamin B12
• C. Vitamin D
• D. Vitamin E

Correct answer: C

Rationale: Vitamin D is the correct answer. It plays a vital role in immune function by regulating the immune system and enhancing the pathogen-fighting effects of monocytes and macrophages. Deficiency in Vitamin D has been linked to increased susceptibility to infections and autoimmune diseases, highlighting its importance in maintaining a healthy immune response. Vitamin A (Choice A) is essential for vision and skin health but is not primarily known for its role in immune function. Vitamin B12 (Choice B) is important for red blood cell formation and neurological function, not specifically immune function. Vitamin E (Choice D) acts as an antioxidant and is beneficial for skin health and cell function, but it is not primarily associated with immune system support.

3. During which phase of the cell cycle does DNA replication occur?

• A. Interphase
• B. Mitosis
• C. Meiosis
• D. Cytokinesis

Correct answer: A

Rationale: Interphase is the phase of the cell cycle where the cell spends the majority of its time and is characterized by three subphases: G1 (Gap 1), S (Synthesis), and G2 (Gap 2). DNA replication specifically occurs during the S phase of interphase. This is a crucial step as it ensures that each daughter cell produced during cell division receives an exact copy of the genetic material. Mitosis is responsible for the equal distribution of the replicated DNA to the daughter cells during cell division. Meiosis is a specialized cell division process for gamete production in sexually reproducing organisms, involving two rounds of division to generate haploid cells. Cytokinesis is the final step of the cell cycle, where the cytoplasm divides to complete the formation of two separate daughter cells following nuclear division.

4. Which cells myelinate neurons in the CNS?

• A. Schwann cells
• B. Astrocytes
• C. Microglia
• D. Oligodendrocytes

Correct answer: D

Rationale: The correct answer is D, Oligodendrocytes. Oligodendrocytes are responsible for myelinating neurons in the central nervous system (CNS). Schwann cells, found in the peripheral nervous system, are responsible for myelinating neurons there. Astrocytes support and maintain the neuronal environment, while microglia function as immune cells in the CNS, participating in immune responses and cellular debris clearance. Therefore, choices A, B, and C are incorrect for myelination of CNS neurons.

5. Which of the following is an example of stabilizing selection?

• A. Selection that favors extreme traits in a population
• B. Selection that removes individuals with extreme traits
• C. Selection that maintains the current average trait in a population
• D. Selection that favors one specific trait over all others

Correct answer: C

Rationale: - Stabilizing selection is a type of natural selection that favors the intermediate variants in a population, while selecting against the extreme traits. This results in the maintenance of the current average trait in the population. - Option A is incorrect because stabilizing selection does not favor extreme traits; instead, it favors the average trait. - Option B is incorrect because stabilizing selection does not remove individuals with extreme traits; it acts against extreme traits by favoring the intermediate variants. - Option D is incorrect because stabilizing selection does not favor one specific trait over all others; it favors the average trait by selecting against extreme traits.

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