Nursing Elites

1. Maintaining a stable internal environment typically requires

• A. positive feedback mechanisms.
• B. an unstable outside environment.
• C. decreased atmospheric pressure.
• D. negative feedback mechanisms.

Correct answer: D

Rationale: The correct answer is 'negative feedback mechanisms.' In biological systems, negative feedback mechanisms help maintain homeostasis by counteracting any deviations from the set point. They work to stabilize internal conditions and keep them within a narrow range. On the other hand, positive feedback mechanisms amplify changes and are not involved in maintaining stability. Choice B, 'an unstable outside environment,' is incorrect as internal stability is independent of external conditions like weather. Choice C, 'decreased atmospheric pressure,' is also incorrect as it does not directly relate to internal homeostasis.

2. What effect does aldosterone secretion have on electrolyte levels?

• A. Calcium levels are decreased
• B. Sodium levels are increased
• C. Potassium levels are increased
• D. Magnesium levels are decreased

Correct answer: B

Rationale: Aldosterone is a hormone that primarily acts on the kidneys to increase the reabsorption of sodium and water into the bloodstream. As a result, sodium levels are increased. Choices A, C, and D are incorrect. Aldosterone does not significantly affect calcium, potassium, or magnesium levels.

3. Which part of the nephron is closest to the collecting duct?

• A. Distal convoluted tubule (DCT)
• B. Bowman's Capsule
• C. Afferent Arteriole
• D. Proximal Convoluted Tubule (PCT)

Correct answer: A

Rationale: The correct answer is the Distal convoluted tubule (DCT). The DCT is the part of the nephron closest to the collecting duct, where the final adjustments to electrolyte and fluid balance are made. Bowman's Capsule is located at the beginning of the nephron, where filtration of blood occurs. The Afferent Arteriole brings blood to the glomerulus for filtration. The Proximal Convoluted Tubule (PCT) is situated after the Bowman's Capsule and is not the part closest to the collecting duct.

4. Which of the following electrolytes plays an essential role in the clotting of blood?

• A. sodium
• B. magnesium
• C. calcium
• D. potassium

Correct answer: C

Rationale: Calcium plays an essential role in the clotting of blood by being involved in several steps of the coagulation process. It is necessary for the conversion of prothrombin to thrombin, which is a crucial step in forming blood clots. Sodium, magnesium, and potassium do not directly participate in the clotting cascade and are not associated with the coagulation process. Therefore, the correct answer is calcium.

5. Do chromosomes get longer as a cell ages?

• A. TRUE
• B. FALSE
• C. Not Sure
• D. None of the above

Correct answer: B

Rationale: Chromosomes do not get longer as a cell ages. In fact, chromosomes condense and become more compact during cell division to ensure proper segregation. Choice A is incorrect because chromosomes do not elongate with age. Choice C is not the correct answer as there is scientific evidence to support that chromosomes do not lengthen over time. Choice D is not the right option as the correct answer is 'False' in this case.

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