Nursing Elites

1. When animals eat, insulin is released from the pancreas, stimulating glucose uptake by the liver. When glucose levels drop, the pancreas reduces insulin release. This is an example of which mechanism for maintaining homeostasis?

• A. Negative feedback.
• B. Positive feedback.
• C. Stress response.
• D. Parasympathetic regulation.

Correct answer: A

Rationale: This mechanism is an example of negative feedback. Negative feedback systems work to counteract changes in the body and maintain a stable internal environment (homeostasis). In this case, the release of insulin in response to high glucose levels is followed by a reduction in insulin release when glucose levels drop. This response helps regulate glucose levels and return them to a normal range, demonstrating the characteristic of negative feedback where the body's response opposes the initial stimulus to maintain equilibrium. Positive feedback would amplify the initial change rather than counteract it, so it is not the correct choice. Stress response and parasympathetic regulation are not directly involved in this glucose regulation process, making them incorrect choices.

2. If every child in a certain family suffers from autism, what possible conclusion can be drawn about autism?

• A. Autism may be lethal.
• B. Autism may be genetic.
• C. Autism is related to traditional nuclear family structures.
• D. No conclusion can be drawn based on this evidence.

Correct answer: B

Rationale: The possible conclusion that can be drawn from every child in a certain family suffering from autism is that autism may be genetic. The fact that every child in the family has autism suggests a strong genetic influence on the condition within this particular family. This does not necessarily mean that autism is solely genetic in all cases, but in this specific family, the pattern of all children being affected points towards a genetic connection. Choice A is incorrect as the information provided does not suggest that autism is lethal. Choice C is incorrect as there is no evidence to support a relationship between autism and traditional nuclear family structures. Choice D is incorrect because a conclusion can be drawn from the given evidence, indicating a potential genetic link within this specific family.

3. What are the finger-like projections that increase the surface area for absorption in the small intestine called?

• A. Crypts of Lieberkühn
• B. Goblet cells
• C. Villi
• D. Paneth cells

Correct answer: C

Rationale: A) Crypts of Lieberkühn are small pits in the lining of the small intestine that contain cells involved in the production of intestinal juices, but they do not increase the surface area for absorption. B) Goblet cells are specialized cells that secrete mucus to protect the lining of the digestive tract, but they do not increase the surface area for absorption. C) Villi are finger-like projections in the small intestine that increase the surface area available for nutrient absorption. Each villus contains blood vessels and lacteals (lymphatic vessels) that help absorb nutrients from digested food. D) Paneth cells are specialized cells found in the small intestine that secrete antimicrobial substances, but they do not increase the surface area for absorption.

4. Which of the following substances is NOT a product of cellular respiration?

• A. Carbon dioxide
• B. Water
• C. Oxygen
• D. ATP

Correct answer: C

Rationale: The correct answer is C. Oxygen is not a product of cellular respiration; instead, it is consumed during the process. During cellular respiration, glucose is broken down in the presence of oxygen to produce energy in the form of ATP, carbon dioxide, and water. Carbon dioxide is released as a waste product, water is a byproduct of the chemical reactions, and ATP is the energy currency used by cells. Therefore, options A, B, and D are all products or outcomes of cellular respiration, while oxygen is a reactant.

5. What phenomenon is responsible for the creation of rainbows?

• A. Reflection only
• B. Diffraction
• C. Refraction and reflection
• D. Polarization

Correct answer: C

Rationale: Rainbows are created by both refraction and reflection of sunlight within water droplets in the atmosphere. When sunlight enters a water droplet, it is refracted, then internally reflected, and finally refracted again as it exits the droplet. This process causes the separation of light into its component colors and the formation of a rainbow. Choice A is incorrect because rainbows are not solely formed by reflection. Choice B, diffraction, is not the primary phenomenon responsible for rainbows. Choice D, polarization, is not directly involved in the creation of rainbows. Therefore, the correct answer is C.

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