Nursing Elites

1. 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.

2. What type of reaction is represented by the following equation: Fe2O3 (s) + 3H2 (g) -> 2Fe (s) + 3H2O (g)?

• A. Combustion
• B. Decomposition
• C. Single displacement
• D. Redox reaction

Correct answer: C

Rationale: The correct answer is C: Single displacement. This reaction is a single displacement reaction because the iron (Fe) in Fe2O3 is displaced by the hydrogen (H) in H2 to form Fe and H2O. In single displacement reactions, one element replaces another in a compound. Choice A, Combustion, involves a reaction with oxygen typically producing heat, light, and often a flame. Choice B, Decomposition, is when a compound breaks down into simpler substances. Choice D, Redox reaction, involves both reduction and oxidation reactions happening simultaneously, which is not the case in the provided equation.

3. What causes stretch marks?

• A. The epidermis layer becomes inflamed
• B. The dermis layer becomes inflamed
• C. The dermis layer tears due to rapid stretching
• D. Sebaceous glands become clogged

Correct answer: C

Rationale: Stretch marks occur when the dermis layer tears due to rapid stretching of the skin. This tearing leads to the appearance of stretch marks, which are often red or purple at first and then fade to a silvery-white color over time. Inflammation of the dermis or clogging of sebaceous glands are not directly related to the formation of stretch marks. Therefore, choices A, B, and D are incorrect as they do not describe the actual cause of stretch marks.

4. What hormone signals the release of digestive enzymes from the pancreas?

• A. Gastrin
• B. Insulin
• C. Glucagon
• D. Secretin

Correct answer: D

Rationale: A) Gastrin is a hormone that stimulates the release of gastric acid in the stomach, not digestive enzymes from the pancreas. B) Insulin is a hormone produced by the pancreas that regulates blood sugar levels by facilitating the uptake of glucose into cells, but it does not directly signal the release of digestive enzymes from the pancreas. C) Glucagon is another hormone produced by the pancreas that works opposite to insulin by increasing blood sugar levels, but it is not involved in signaling the release of digestive enzymes from the pancreas. D) Secretin is a hormone released by the small intestine in response to the presence of acidic chyme. It stimulates the pancreas to release bicarbonate to neutralize the acidity of the chyme and also triggers the release of digestive enzymes from the pancreas to aid in digestion. Therefore, secretin is the hormone that signals the release of digestive enzymes from the pancreas.

5. What is the SI unit of measurement for acceleration?

• A. Meters per second (m/s)
• B. Newton (N)
• C. Meters (m)
• D. Meters per second squared (m/s²)

Correct answer: D

Rationale: The SI unit of measurement for acceleration is meters per second squared (m/s²). Acceleration is defined as the rate of change of velocity over time. It is a vector quantity with dimensions of length per time squared. Meters per second squared (m/s²) represents the change in velocity (meters per second) over a specific time interval (seconds) squared. Choice A, meters per second (m/s), represents velocity, not acceleration. Choice B, Newton (N), is the unit of force. Choice C, Meters (m), represents only distance, not acceleration. Therefore, the correct unit for acceleration is meters per second squared (m/s²).

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