Nursing Elites

1. Which of the following is NOT a tissue layer found in skeletal bone?

• A. periosteum
• B. bone marrow
• C. enamel
• D. cancellous bone

Correct answer: C

Rationale: Enamel is a hard, outer layer that covers the crown of a tooth and is not a tissue layer found in skeletal bone. The other options, periosteum, bone marrow, and cancellous bone, are all tissue layers or components found in skeletal bone. Periosteum is the connective tissue layer covering the bone surface, bone marrow is found within the bone cavities, and cancellous bone is a spongy, porous bone tissue.

2. Why is the electrical conductivity of a strong acid solution higher than that of a weak acid solution?

• A. Strong acids are more concentrated.
• B. Strong acids release more hydrogen ions.
• C. Weak acids are better at dissolving salts.
• D. Strong acids have a lower pH.

Correct answer: B

Rationale: The correct answer is B because strong acids release more hydrogen ions compared to weak acids. This higher concentration of ions in the solution leads to a higher electrical conductivity. Strong acids ionize completely in solution, producing a higher concentration of ions that can conduct electricity, whereas weak acids only partially ionize, resulting in a lower concentration of ions and lower electrical conductivity. Choice A is incorrect because the concentration of the acid does not directly determine its electrical conductivity. Choice C is incorrect as the ability to dissolve salts is not directly related to electrical conductivity. Choice D is incorrect because the pH of the solution, although related to acidity, does not directly determine the electrical conductivity.

3. In an SN2 reaction, what affects the rate of the reaction?

• A. Only the concentration of the nucleophile
• B. Only the concentration of the electrophile
• C. Neither the concentration of the nucleophile nor the electrophile
• D. Both the concentration of the nucleophile and the electrophile

Correct answer: D

Rationale: In an SN2 reaction, the rate of the reaction is affected by both the concentration of the nucleophile and the electrophile. The rate-determining step involves the nucleophile attacking the electrophile, so the concentrations of both species will impact the reaction rate. Increasing the concentration of the nucleophile increases the frequency of nucleophilic attacks, while increasing the concentration of the electrophile provides more opportunities for the nucleophile to react. Therefore, the correct answer is that both the concentration of the nucleophile and the electrophile affect the rate of the SN2 reaction. Choices A, B, and C are incorrect as they do not consider the interplay between the nucleophile and the electrophile in determining the overall reaction rate in an SN2 mechanism.

4. What controls the involuntary, rhythmic contractions of the heart muscle?

• A. Lungs
• B. Brain
• C. Spinal cord
• D. Sinoatrial node (located within the heart)

Correct answer: D

Rationale: The correct answer is D: Sinoatrial node (located within the heart). The involuntary, rhythmic contractions of the heart muscle are controlled by a specialized group of cells located within the heart called the sinoatrial node (SA node). The SA node acts as the heart's natural pacemaker, producing electrical impulses that regulate the heart rate and synchronize the contractions of the heart muscle. Choices A, B, and C (Lungs, Brain, Spinal cord) are not responsible for directly influencing the rhythmic contractions of the heart muscle.

5. Which of the following minerals is important for bone health and is stored in bones by the skeletal system?

• A. Iron
• B. Sodium
• C. Calcium
• D. Magnesium

Correct answer: C

Rationale: The correct answer is Calcium (Choice C). Calcium is essential for bone health and is stored in bones by the skeletal system. Bones act as a reservoir for calcium, playing a critical role in maintaining bone strength and density. Iron, sodium, and magnesium are important for various bodily functions but are not primarily stored in bones for bone health. Iron is crucial for oxygen transport, sodium helps regulate fluid balance, and magnesium is involved in over 300 enzymatic reactions in the body.

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