Nursing Elites

1. Which feedback loop inhibits the stimulus or the deviation from homeostasis?

• A. Negative feedback loop
• B. Positive feedback loop
• C. Inhibitory feedback loop
• D. Stimulating feedback loop

Correct answer: A

Rationale: The correct answer is A: Negative feedback loop. Negative feedback loops work to inhibit the stimulus or reduce the deviation from a set point, maintaining homeostasis by counteracting any changes from the norm. In this case, the negative feedback loop acts to minimize any deviation from the body's internal balance, ensuring stability and optimal functioning. Choice B, a positive feedback loop, amplifies the stimulus or deviation, moving systems away from homeostasis. Choice C, an inhibitory feedback loop, is not a commonly recognized term in the context of feedback mechanisms. Choice D, a stimulating feedback loop, is not a standard term and does not accurately describe a feedback loop's role in maintaining homeostasis.

2. Which organ system is most responsible for maintaining control of body temperature?

• A. The skeletal system.
• B. The circulatory system.
• C. The immune system.
• D. The muscular system.

Correct answer: B

Rationale: The circulatory system is the correct answer as it plays a crucial role in maintaining control of body temperature through a process called thermoregulation. Blood vessels near the skin surface dilate to dissipate heat when the body is too warm and constrict to reduce heat loss when it's too cold. Additionally, the circulatory system helps distribute heat produced from metabolic processes throughout the body to keep a stable internal temperature. The skeletal system provides structural support, the immune system defends against pathogens, and the muscular system is responsible for movement, but they are not primarily involved in regulating body temperature.

3. Which of the following is an example of a polymer?

• A. Methane
• B. Ethanol
• C. Polyethylene
• D. Acetic acid

Correct answer: C

Rationale: The correct answer is C, Polyethylene. Polyethylene is a polymer composed of a large number of repeating ethylene units linked together, forming a long-chain molecule, characteristic of polymers. Methane, ethanol, and acetic acid are small organic molecules that do not demonstrate the repeating unit structure typical of polymers. Therefore, they are not examples of polymers.

4. Homologous structures are those that:

• A. Have the same function but different origins
• B. Have different functions but the same origin
• C. Are similar in appearance and function due to shared ancestry
• D. Are identical in both appearance and function

Correct answer: C

Rationale: Homologous structures are defined as anatomical features that are similar in appearance and function due to shared ancestry. This means that these structures are inherited from a common ancestor and may have evolved to fulfill different functions in different species. Option A, which mentions structures with the same function but different origins, describes analogous structures, not homologous ones. Option B, which refers to structures with different functions but the same origin, actually characterizes vestigial structures. Option D, stating that structures are identical in appearance and function, does not necessarily imply homology; such structures could result from convergent evolution rather than shared ancestry. Understanding homologous structures provides insights into the evolutionary relationships between different species and supports the concept of common descent.

5. What property of a substance remains constant regardless of changes in its shape or size?

• A. Mass
• B. Weight
• C. Density
• D. Volume

Correct answer: A

Rationale: Mass is a measure of the amount of matter in an object and remains constant regardless of changes in its shape or size. Weight, density, and volume can all change depending on the conditions, but mass remains the same. For example, if you have a piece of clay and you shape it into a ball or flatten it into a pancake, the amount of clay (mass) will remain the same, even though the shape and size have changed. Weight is the force acting on an object due to gravity, which can vary depending on the gravitational pull. Density is the mass per unit volume, so it changes with variations in volume. Volume is the amount of space occupied by an object, which can change if the shape or size of the object is altered.

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