Nursing Elites

1. What is the myelin sheath and what does it do?

• A. A group of nerve cells that perform a specific function.
• B. A fatty substance that insulates some nerve fibers.
• C. A fluid-filled cavity within the brain.
• D. The junction between two neurons.

Correct answer: B

Rationale: The myelin sheath is a fatty substance that insulates some nerve fibers. It is made up of specialized cells that wrap around the axons of neurons, providing insulation and speeding up the transmission of nerve impulses. Choice A is incorrect as the myelin sheath is not a group of nerve cells but rather a substance that surrounds nerve fibers. Choice C is incorrect as the myelin sheath is not a fluid-filled cavity within the brain. Choice D is incorrect as the myelin sheath is not the junction between two neurons.

2. From an anterior view, which of the following vessels carries blood away from the heart?

• A. Left common carotid artery
• B. Pulmonary trunk
• C. Subclavian arteries
• D. All of the above

Correct answer: D

Rationale: The correct answer is D, 'All of the above.' When viewed from an anterior perspective, the left common carotid artery, pulmonary trunk, and subclavian arteries all carry blood away from the heart. The left common carotid artery supplies oxygenated blood to the head and neck, the pulmonary trunk carries deoxygenated blood to the lungs for oxygenation, and the subclavian arteries transport blood to the upper extremities. Therefore, all the vessels listed in the choices are correct as they function to carry blood away from the heart when viewed anteriorly.

3. Which of the following correctly lists the four properties that all types of muscle tissue share?

• A. Contractile, excitable, elastic, extensible
• B. Contractile, voluntary, elastic, extensible
• C. Contractile, excitable, voluntary, extensible
• D. Contractile, excitable, elastic, voluntary

Correct answer: A

Rationale: The correct answer is A: 'Contractile, excitable, elastic, extensible.' All types of muscle tissue share these four properties. Muscle tissue can contract, respond to stimuli, stretch and return to its original shape (elastic), and extend or stretch (extensible). Choice B is incorrect because not all muscle tissues are voluntary (some are involuntary). Choice C is incorrect because not all muscle tissues are voluntary. Choice D is incorrect because not all muscle tissues are voluntary and lack the elastic property.

4. What phenomenon explains the formation of rainbows in the sky?

• A. Diffraction
• B. Interference
• C. Refraction and dispersion of sunlight by water droplets
• D. Reflection from clouds

Correct answer: C

Rationale: Rainbows are formed due to the refraction and dispersion of sunlight by 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 dispersion of light into its component colors creates the beautiful rainbow we see in the sky. Choice A, diffraction, involves bending of light around obstacles or through narrow openings, not the splitting of light into colors as seen in rainbows. Choice B, interference, refers to the phenomenon where two or more light waves overlap and interact, producing a pattern of light and dark bands, which is not the case with rainbows. Choice D, reflection from clouds, does not accurately describe the process involved in the formation of rainbows through refraction and dispersion of light by water droplets.

5. What is the term for the chemical reaction that involves the loss of electrons?

• A. Reduction
• B. Oxidation
• C. Neutralization
• D. Precipitation

Correct answer: B

Rationale: Oxidation is the process where a substance loses electrons. In an oxidation reaction, the substance being oxidized loses electrons, which are gained by another substance. Reduction is the opposite process, where a substance gains electrons. Neutralization is a reaction between an acid and a base to form a salt and water. Precipitation is the formation of a solid from a solution. Therefore, in the context of a chemical reaction involving the loss of electrons, the correct term is oxidation (Choice B).

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