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. Which of the following is the measurement of the percentage of red blood cells in whole blood?

• A. Hematocrit
• B. Hemoglobin
• C. Mean corpuscular volume
• D. Reticulocyte count

Correct answer: A

Rationale: The correct answer is 'Hematocrit.' Hematocrit is the measurement of the percentage of red blood cells in whole blood. It is used to diagnose conditions such as anemia and dehydration. Choice B, 'Hemoglobin,' measures the amount of hemoglobin in the blood, not the percentage of red blood cells. Choice C, 'Mean corpuscular volume,' measures the average volume of a red blood cell, not the percentage of red blood cells. Choice D, 'Reticulocyte count,' measures the percentage of young red blood cells in the blood, not the percentage of red blood cells.

3. Does the digestive system filter wastes from the blood?

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

Correct answer: B

Rationale: The correct answer is False. The digestive system is responsible for breaking down food and absorbing nutrients, not filtering wastes from the blood. The excretory system, particularly the kidneys, filters wastes from the blood to form urine. Choices A, C, and D are incorrect because the digestive system's primary function is not waste filtration but rather digestion and absorption of nutrients.

4. The thoracic cavity lies _____________ the abdominopelvic cavity.

• A. dorsal (posterior) to
• B. ventral (anterior) to
• C. superior to
• D. inferior to

Correct answer: C

Rationale: The correct answer is 'superior to.' The thoracic cavity is located above the abdominopelvic cavity, making it superior. The term 'dorsal (posterior) to' refers to the back side, 'ventral (anterior) to' indicates the front side, and 'inferior to' means below. In the context of body cavities, the thoracic cavity is positioned higher than the abdominopelvic cavity, making 'superior to' the most appropriate choice.

5. Signs of aging at the cellular level are

• A. graying hair, waning strength, and wrinkles.
• B. unrepaired DNA and abnormal proteins.
• C. impaired cell division and the ability to break down and recycle worn cell parts.
• D. a fatty liver and clogged blood vessels.

Correct answer: C

Rationale: The correct answer is 'impaired cell division and the ability to break down and recycle worn cell parts.' Aging at the cellular level involves reduced efficiency in cell division and the breakdown/recycling of cellular components, leading to functional decline. Choices A, B, and D are incorrect because they involve external physical manifestations or organ-specific issues rather than cellular-level changes associated with aging.

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