Nursing Elites

1. The endocrine system communicates through chemical messengers called:

• A. Enzymes
• B. Hormones
• C. Antibodies
• D. Neurons

Correct answer: B

Rationale: The correct answer is B: Hormones. The endocrine system communicates through hormones, which are chemical messengers produced by glands and released into the bloodstream to target specific cells or organs in the body. Enzymes are biological molecules that catalyze biochemical reactions, antibodies are part of the immune system, and neurons are cells that transmit nerve impulses. In this context, enzymes, antibodies, and neurons do not play roles in the endocrine system's communication process, making them incorrect choices.

2. How many micrograms are in 1 milligram?

• A. 1 µg
• B. 10 µg
• C. 100 µg
• D. 1,000 µg

Correct answer: D

Rationale: The correct answer is D: 1,000 µg. To convert milligrams to micrograms, you need to multiply by 1,000 because there are 1,000 micrograms in 1 milligram. Choices A, B, and C are incorrect because they do not correctly convert milligrams to micrograms. 1 milligram is equal to 1,000 micrograms, making choice D the right answer.

3. What is the valve that prevents blood from flowing back from the left ventricle into the left atrium?

• A. Tricuspid valve
• B. Mitral valve
• C. Aortic valve
• D. Pulmonic valve

Correct answer: B

Rationale: The correct answer is the Mitral valve. The mitral valve is located between the left atrium and the left ventricle of the heart. Its function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. Choice A, the Tricuspid valve, is incorrect as it is located between the right atrium and right ventricle. Choice C, the Aortic valve, and Choice D, the Pulmonic valve, are also incorrect as they are involved in the circulation of blood leaving the heart rather than preventing backflow within the atria and ventricles.

4. What is the name for the process where a solid changes directly into a gas?

• A. Evaporation
• B. Sublimation
• C. Condensation
• D. Melting

Correct answer: B

Rationale: Sublimation is the process by which a solid directly transforms into a gas without passing through the liquid phase. This occurs when the atmospheric pressure is lower than the vapor pressure of the solid, causing it to transition to a gas state. Choice A, evaporation, is the process where a liquid changes into a gas, not a solid. Choice C, condensation, is the opposite process where gas changes into a liquid. Choice D, melting, is the process where a solid changes into a liquid, not a gas.

5. Delta waves, associated with deep sleep, exhibit what frequency range?

• A. 0.5-4 Hz
• B. 4-8 Hz
• C. 8-13 Hz
• D. 13-30 Hz

Correct answer: A

Rationale: Delta waves are slow brain waves associated with deep sleep stages, specifically stages 3 and 4 of non-REM sleep. These waves have a frequency range of 0.5-4 Hz. Choice B (4-8 Hz) refers to theta waves, which are associated with light sleep and relaxation. Choice C (8-13 Hz) corresponds to alpha waves, present during wakeful relaxation. Choice D (13-30 Hz) represents beta waves, seen in active thinking and concentration. Therefore, the correct answer is A because it aligns with the frequency range characteristic of delta waves during deep sleep.

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