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. If the mass of an object remains constant and its velocity doubles, how does its momentum change?

• A. Momentum doubles
• B. Momentum halves
• C. Momentum quadruples
• D. Momentum remains the same

Correct answer: C

Rationale: Momentum is calculated as the product of an object's mass and its velocity. When the mass remains constant and the velocity doubles, the momentum will increase by a factor of 2 (doubling) due to the increase in velocity. Therefore, the momentum will quadruple (2 x 2 = 4) when the velocity doubles. This relationship between momentum and velocity showcases the direct proportionality of momentum to velocity, given a constant mass. Choices A, B, and D are incorrect. Momentum does not simply double or halve when the velocity doubles; it quadruples as it is directly proportional to the velocity. Hence, the correct answer is C, where momentum quadruples in this scenario.

3. What is the scientific unit used to measure the radioactivity of a substance?

• A. Becquerel (Bq)
• B. Joule (J)
• C. Newton (N)
• D. Kelvin (K)

Correct answer: A

Rationale: The correct answer is A: Becquerel (Bq). The Becquerel (Bq) is the scientific unit used to measure the radioactivity of a substance. It is named after Henri Becquerel, who discovered radioactivity. The Joule (J) is the unit of energy, Newton (N) is the unit of force, and Kelvin (K) is the unit of temperature. When measuring radioactivity, the Becquerel is used to quantify the rate of radioactive decay in a substance. Choices B, C, and D are incorrect as they represent units for energy, force, and temperature, respectively, not radioactivity.

4. Which hormone is produced by the thyroid gland?

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

Correct answer: B

Rationale: The correct answer is B: Thyroxine. The thyroid gland produces thyroxine, a hormone essential for regulating metabolism. Insulin is produced by the pancreas to regulate blood sugar levels. Adrenaline is produced by the adrenal glands to prepare the body for the 'fight or flight' response. Cortisol is produced by the adrenal cortex in response to stress, not by the thyroid gland.

5. Where is fat primarily digested, and where is protein primarily digested?

• A. Mouth; stomach
• B. Stomach; small intestine
• C. Small intestine; small intestine
• D. Small intestine; stomach

Correct answer: B

Rationale: The correct answer is B. Fats are primarily digested in the small intestine, where bile from the liver emulsifies fats for enzymatic digestion. The small intestine is where most of the absorption of nutrients occurs. Proteins, on the other hand, are mainly digested in the stomach by the enzyme pepsin under acidic conditions. The stomach's acidic environment helps denature proteins, making them more accessible to pepsin for digestion. Choices A, C, and D are incorrect because they do not accurately reflect the primary sites of fat and protein digestion in the human digestive system.

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