Nursing Elites

1. What is the function of the myelin sheath in a neuron?

• A. To transmit electrical impulses
• B. To insulate and speed up electrical signals
• C. To produce neurotransmitters
• D. To protect the neuron from damage

Correct answer: B

Rationale: The myelin sheath serves to insulate neurons and accelerate the transmission of electrical signals along the axon. This insulation helps in the efficient conduction of nerve impulses by preventing signal loss or leakage. Choice A is incorrect because the myelin sheath does not transmit electrical impulses itself but rather helps in the conduction. Choice C is incorrect as the myelin sheath is not responsible for producing neurotransmitters. Choice D is also incorrect as the primary function of the myelin sheath is not to protect the neuron from damage. Therefore, the correct answer is B, as it accurately describes the function of the myelin sheath in a neuron.

2. What is the role of hemoglobin in red blood cells?

• A. To carry carbon dioxide to the lungs
• B. To carry oxygen from the lungs to the body
• C. To regulate blood pressure
• D. To produce white blood cells

Correct answer: B

Rationale: Hemoglobin in red blood cells functions to carry oxygen from the lungs to tissues in the body. It binds to oxygen in the lungs and releases it to the body's cells, ensuring they have an adequate oxygen supply for metabolic processes. Choice A is incorrect because hemoglobin primarily carries oxygen, not carbon dioxide. Choice C is incorrect because hemoglobin's role is not related to blood pressure regulation. Choice D is incorrect because hemoglobin is not involved in the production of white blood cells.

3. What happens to the density of a gas when its temperature increases at constant pressure?

• A. It increases.
• B. It decreases.
• C. It remains the same.
• D. Information is insufficient.

Correct answer: B

Rationale: When the temperature of a gas increases at constant pressure, the average kinetic energy of the gas molecules increases. This leads to the gas molecules moving faster and spreading out more, which causes them to occupy a larger volume. As a result, the density of the gas decreases because the same number of gas molecules are now distributed over a larger space. Choice A is incorrect because as the gas molecules spread out, the density decreases. Choice C is incorrect because the increase in temperature leads to a decrease in density due to the increased volume occupied by the gas molecules. Choice D is incorrect because with the provided scenario of temperature increase at constant pressure, the effect on density can be determined.

4. Which hormone regulates the sleep-wake cycle?

• A. Cortisol
• B. Melatonin
• C. Thyroxine
• D. Insulin

Correct answer: B

Rationale: The correct answer is B: Melatonin. Melatonin, produced by the pineal gland, is the hormone that regulates the sleep-wake cycle. It helps signal to the body when it's time to sleep and wake up, playing a crucial role in maintaining a healthy sleep pattern. Choice A, Cortisol, is known as the stress hormone and plays a role in the body's response to stress, not specifically in regulating the sleep-wake cycle. Choice C, Thyroxine, is a hormone produced by the thyroid gland that regulates metabolism, not the sleep-wake cycle. Choice D, Insulin, is a hormone produced by the pancreas that regulates blood sugar levels, not the sleep-wake cycle.

5. Which skin condition is characterized by red, itchy, and inflamed patches?

• A. Eczema
• B. Psoriasis
• C. Melanoma
• D. Keloid

Correct answer: A

Rationale: Eczema is a skin condition characterized by red, itchy, and inflamed patches. It is a common condition that can vary in severity and often presents with symptoms such as dry, scaly skin, and sometimes oozing or crusting. Psoriasis, on the other hand, presents with red, scaly patches but is not typically described as itchy. Melanoma is a type of skin cancer characterized by the development of abnormal moles, while keloid is a type of raised scar that can occur after an injury to the skin. Therefore, the correct answer is eczema due to its specific symptom presentation of red, itchy, and inflamed patches.

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