Nursing Elites

1. What is the main function of the epiglottis, a small flap of cartilage located above the larynx?

• A. To warm and humidify inhaled air
• B. To control the passage of food and air
• C. To produce sound vibrations for speech
• D. To sense the presence of foreign objects

Correct answer: B

Rationale: The main function of the epiglottis is to control the passage of food and air. It acts as a cover for the trachea during swallowing to prevent food from entering the airway. This mechanism ensures that food safely travels down the esophagus to the stomach, while air simultaneously enters the trachea and moves into the lungs for respiration. Choice A is incorrect as the warming and humidifying of inhaled air primarily occur in the nasal cavity. Choice C is incorrect because sound production for speech involves structures like the vocal cords rather than the epiglottis. Choice D is incorrect as sensing foreign objects is not a primary function of the epiglottis; instead, this role is typically associated with sensory receptors in the respiratory tract.

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. In the reaction 2H2 + O2 → 2H2O, how many moles of oxygen are required to react completely with 4 moles of hydrogen?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: B

Rationale: The balanced chemical equation indicates that 2 moles of H2 react with 1 mole of O2 to produce 2 moles of H2O. To determine how many moles of O2 are required to react with 4 moles of H2, you can use the mole ratio from the balanced equation: 2 moles of H2 react with 1 mole of O2. Therefore, to react completely with 4 moles of H2, you would need 2 moles of O2 (4 moles H2 ÷ 2 moles H2 per 1 mole O2). Hence, 2 moles of oxygen are required to react completely with 4 moles of hydrogen. Choices A, C, and D are incorrect because they do not reflect the correct stoichiometry as defined by the balanced chemical equation.

4. Which of the following brain structures is responsible for emotions, emotional behavior, and motivation?

• A. Amygdala
• B. Cerebellum
• C. Hypothalamus
• D. Pons

Correct answer: A

Rationale: The correct answer is the amygdala. The amygdala is a key brain structure involved in processing emotions, emotional behavior, and motivation. It plays a crucial role in fear responses, emotional memories, and social behaviors. The cerebellum (Choice B) is primarily responsible for coordination and balance, not emotions. The hypothalamus (Choice C) regulates basic survival functions like hunger, thirst, and body temperature, but it is not primarily responsible for emotions. The pons (Choice D) is involved in functions such as sleep, respiration, and bladder control, but it is not the main center for emotions, emotional behavior, or motivation.

5. Which statement correctly describes the concept of ionization energy?

• A. The energy required to remove an electron from an outermost shell.
• B. The energy released when an electron bonds with an atom.
• C. The total energy possessed by all electrons in an atom.
• D. The energy needed to change an atom's nucleus.

Correct answer: A

Rationale: Ionization energy is defined as the energy required to remove an electron from an atom in the gaseous state. This process typically involves removing an electron from the outermost shell of the atom. Therefore, option A accurately describes the concept of ionization energy. The other choices do not accurately describe ionization energy; option B refers to bond formation energy, option C is about the total energy of electrons in an atom, and option D relates to nuclear energy changes, not ionization energy.

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