Nursing Elites

1. Positive feedback mechanisms usually result in

• A. changes returning values away from a set point.
• B. stable conditions around a set point.
• C. unstable conditions.
• D. long-term changes.

Correct answer: C

Rationale: Positive feedback mechanisms usually result in unstable conditions. In a positive feedback loop, the output enhances or amplifies the changes that are occurring, leading to a deviation from the initial set point. Therefore, positive feedback does not bring values back towards the set point (Choice A). Choice B is incorrect because positive feedback does not promote stability around a set point. Choice D is also incorrect as positive feedback mechanisms typically do not lead to long-term changes; instead, they intensify the initial change, causing instability.

2. Living organisms use oxygen to __________________.

• A. reduce heat production
• B. accept electrons for cellular metabolism
• C. release energy stored in the molecules of food
• D. remove metabolic wastes

Correct answer: C

Rationale: The correct answer is C. Living organisms use oxygen to release energy stored in the molecules of food through a process called cellular respiration. This process involves breaking down glucose molecules in the presence of oxygen to produce energy in the form of ATP. Choice A is incorrect because oxygen does not directly reduce heat production in organisms. Choice B is incorrect because oxygen is involved in accepting electrons rather than donating them in cellular metabolism. Choice D is incorrect because the removal of metabolic wastes is not the primary role of oxygen in living organisms.

3. What causes wrinkled and sagging skin?

• A. Drinking too much water
• B. Heredity alone
• C. Loss of subcutaneous fat and reduced levels of elastin and collagen
• D. Excess subcutaneous fat

Correct answer: C

Rationale: Wrinkled and sagging skin is primarily caused by the loss of subcutaneous fat and reduced levels of elastin and collagen in the skin. Choice A is incorrect as drinking too much water does not lead to wrinkled and sagging skin. Choice B is incorrect because heredity alone does not cause this condition. Excess subcutaneous fat, as mentioned in Choice D, can contribute to a different skin appearance, such as puffiness, but not wrinkled and sagging skin.

4. Magnetic resonance imaging might be used to

• A. distinguish between normal and abnormal tissue.
• B. examine an injured knee.
• C. provide detailed images of the brain.
• D. do both A and B.

Correct answer: B

Rationale: Magnetic resonance imaging, commonly known as MRI, is a non-invasive imaging technique used to visualize internal structures of the body. While it can be used to distinguish between normal and abnormal tissue, one of its common applications is to examine musculoskeletal injuries, such as an injured knee. Choice A has been corrected to mention 'normal and abnormal tissue' instead of 'normal and cancerous tissue' as MRI is not solely used for cancer detection. Choice C is incorrect as MRI can provide detailed images of various body parts, not just limited to the brain. Therefore, the correct answer is to examine an injured knee.

5. Which of the following processes does not help maintain the life of an individual organism?

• A. Responsiveness
• B. Movement
• C. Reproduction
• D. Respiration

Correct answer: C

Rationale: Reproduction is the correct answer because it is not essential for maintaining the life of an individual organism. While reproduction is crucial for the continuation of a species, it is not directly related to the survival or maintenance of an individual organism. Responsiveness allows an organism to react to stimuli, movement helps in obtaining resources and avoiding danger, and respiration provides the necessary energy for life processes. Therefore, reproduction is the process that does not directly contribute to maintaining the life of an individual organism.

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