Nursing Elites

1. What is the main component that gives bones their rigidity and hardness?

• A. Collagen
• B. Calcium phosphate
• C. Cartilage
• D. Ligaments

Correct answer: B

Rationale: Calcium phosphate is the main component that gives bones their rigidity and hardness. It combines with calcium hydroxide to form hydroxyapatite crystals, which provide strength and structure to bones. Collagen, on the other hand, provides flexibility and tensile strength. Cartilage is a type of connective tissue found in joints, and ligaments are fibrous tissues that connect bones to other bones, but they do not contribute to the rigidity and hardness of bones.

2. Which cells myelinate neurons in the CNS?

• A. Schwann cells
• B. Astrocytes
• C. Microglia
• D. Oligodendrocytes

Correct answer: D

Rationale: The correct answer is D, Oligodendrocytes. Oligodendrocytes are responsible for myelinating neurons in the central nervous system (CNS). Schwann cells, found in the peripheral nervous system, are responsible for myelinating neurons there. Astrocytes support and maintain the neuronal environment, while microglia function as immune cells in the CNS, participating in immune responses and cellular debris clearance. Therefore, choices A, B, and C are incorrect for myelination of CNS neurons.

3. Which part of the nervous system controls the 'fight or flight' response?

• A. Central nervous system
• B. Peripheral nervous system
• C. Autonomic nervous system
• D. Sympathetic nervous system

Correct answer: D

Rationale: The correct answer is the sympathetic nervous system. It controls the 'fight or flight' response by preparing the body for stressful situations. The central nervous system (Choice A) consists of the brain and spinal cord but does not directly control the 'fight or flight' response. The peripheral nervous system (Choice B) includes nerves outside the brain and spinal cord, while the autonomic nervous system (Choice C) regulates involuntary bodily functions but is not specific to the 'fight or flight' response.

4. In which units is the speed of light in a vacuum measured?

• A. Meters per second
• B. Hertz
• C. Candela
• D. Newton

Correct answer: A

Rationale: The speed of light in a vacuum is commonly measured in units of meters per second. This is because the speed of light is approximately 299,792,458 meters per second in a vacuum, as defined by the International System of Units (SI). The speed of light is a measure of distance covered by light in a given time, hence it is expressed in meters per second. Choices B, C, and D are incorrect. Hertz is a unit of frequency, Candela is a unit of luminous intensity, and Newton is a unit of force. None of these units are relevant for measuring the speed of light, making 'Meters per second' the correct unit of measurement for the speed of light.

5. What is the relationship between the speed of a wave, its frequency, and wavelength in a given medium?

• A. Speed = Frequency × Wavelength
• B. Speed = Frequency ÷ Wavelength
• C. Speed = Frequency + Wavelength
• D. Speed = Frequency - Wavelength

Correct answer: A

Rationale: The speed of a wave in a given medium is determined by the product of its frequency and wavelength. This relationship is described by the formula: Speed = Frequency × Wavelength. When a wave travels through a medium, the speed at which it propagates is directly proportional to both its frequency and wavelength. Therefore, to calculate the speed of the wave, you multiply the frequency of the wave by its wavelength. Choices B, C, and D are incorrect because speed is not determined by division, addition, or subtraction of frequency and wavelength; instead, it is determined by their multiplication in the given medium.

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