Nursing Elites

1. What is the term for the maximum amount of solute that can dissolve in a solvent at a specific temperature and pressure?

• A. Molarity
• B. Solubility
• C. Concentration
• D. Saturation

Correct answer: B

Rationale: Solubility is the correct term for the maximum amount of solute that can dissolve in a solvent at a specific temperature and pressure. Molarity is a measure of concentration, not the maximum amount that can dissolve. Concentration is a general term for the amount of solute present in a given amount of solvent. Saturation is related to solubility but specifically refers to a state where no more solute can be dissolved in the solvent.

2. What is the small repeating unit in the contractile apparatus of skeletal muscle?

• A. Myofibril
• B. Actin
• C. Sarcomere
• D. Myosin

Correct answer: C

Rationale: The correct answer is 'Sarcomere.' The sarcomere is the smallest repeating unit within myofibrils and is responsible for muscle contraction in skeletal muscle. It consists of overlapping actin and myosin filaments arranged in a highly organized structure that allows for the sliding of filaments during muscle contraction. 'Myofibril' (choice A) is incorrect because it is a larger structure composed of sarcomeres. 'Actin' (choice B) and 'Myosin' (choice D) are incorrect as they are individual proteins that are components of the sarcomere, not the smallest repeating unit itself.

3. Which hormone, produced by the thyroid gland, plays a key role in regulating calcium levels in the blood by promoting calcium release from bones and increasing calcium reabsorption in the kidneys?

• A. Calcitonin
• B. Parathyroid hormone (PTH)
• C. Thyroxine
• D. Insulin

Correct answer: A

Rationale: Calcitonin, produced by the thyroid gland, is responsible for regulating calcium levels in the blood. It works by decreasing blood calcium levels through two main mechanisms: promoting calcium uptake by bones and decreasing calcium reabsorption in the kidneys. Parathyroid hormone (PTH), on the other hand, increases blood calcium levels by promoting calcium release from bones and increasing calcium absorption in the intestines. Thyroxine, another thyroid hormone, primarily regulates metabolism and has no direct influence on calcium levels. Insulin, produced by the pancreas, is involved in regulating blood sugar levels and is not related to calcium homeostasis.

4. What is the term for a solution that has a lower concentration of solute compared to another solution?

• A. Saturated solution
• B. Unsaturated solution
• C. Dilute solution
• D. Concentrated solution

Correct answer: B

Rationale: An unsaturated solution is the term used for a solution that has a lower concentration of solute compared to another solution. In an unsaturated solution, more solute could still be dissolved. The other options are incorrect. A saturated solution (A) contains the maximum amount of solute that can be dissolved and is in equilibrium with undissolved solute. A dilute solution (C) has a low concentration of solute, but it does not imply a comparison to another solution. A concentrated solution (D) has a high concentration of solute compared to the solvent, which is opposite to what is described in the question.

5. In the context of the cardiac cycle, what does the P wave on an electrocardiogram (ECG) represent?

• A. Atrial depolarization
• B. Ventricular depolarization
• C. Atrial repolarization
• D. Ventricular repolarization

Correct answer: A

Rationale: The P wave on an electrocardiogram (ECG) represents atrial depolarization, which signifies the electrical activation of the atria as they prepare to contract. During the cardiac cycle, atrial depolarization occurs first, leading to atrial contraction. Ventricular depolarization is represented by the QRS complex, not the P wave. Choices B, C, and D are incorrect because the P wave specifically corresponds to atrial depolarization, not ventricular depolarization, atrial repolarization, or ventricular repolarization.

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