Nursing Elites

1. Which hormone, produced by the thyroid gland, plays a crucial role in regulating the body's metabolism, growth, and development?

• A. Calcitonin
• B. Parathyroid hormone (PTH)
• C. Thyroxine
• D. Insulin

Correct answer: C

Rationale: Thyroxine, also known as T4, is a hormone produced by the thyroid gland that plays a crucial role in regulating the body's metabolism, growth, and development. It helps control the rate at which the body uses energy, affects protein synthesis, and influences the body's sensitivity to other hormones. Calcitonin (A) is another hormone produced by the thyroid gland, but its primary function is to regulate calcium levels in the blood. Parathyroid hormone (PTH) (B) is produced by the parathyroid glands and is involved in regulating calcium and phosphorus levels in the body. Insulin (D) is a hormone produced by the pancreas that helps regulate blood sugar levels.

2. What is the function of the sinuses?

• A. To trap many airborne pathogens
• B. To direct air down the trachea rather than the esophagus
• C. To warm, humidify, and filter air
• D. To sweep away pathogens and direct them toward the top of the trachea

Correct answer: C

Rationale: The correct function of the sinuses is to warm, humidify, and filter the air we breathe. Sinuses play a crucial role in preparing the air for the respiratory system by adding moisture, warmth, and filtering out particles. Choice A is incorrect because while sinuses can help filter some particles, their primary function is not to trap pathogens. Choice B is incorrect as the sinuses do not control the direction of air down the trachea; this is regulated by the epiglottis and vocal cords. Choice D is incorrect as sinuses do not sweep pathogens away or direct them towards the trachea; instead, they condition the air for respiration.

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. What is the energy required to break a chemical bond called?

• A. Kinetic energy
• B. Potential energy
• C. Activation energy
• D. Bond energy

Correct answer: C

Rationale: Activation energy is the energy required to break a chemical bond and initiate a chemical reaction. It is the minimum amount of energy needed to start a chemical reaction by breaking bonds in the reactant molecules. Kinetic energy (option A) is the energy of motion and is not directly related to breaking chemical bonds. Potential energy (option B) is stored energy that can be converted into other forms of energy but is not specifically about breaking chemical bonds. Bond energy (option D) refers to the energy required to break a particular chemical bond in a molecule and is not the general term for the energy needed to break any chemical bond. Activation energy is crucial in determining the rate of a chemical reaction as it affects the probability of reactant molecules colliding with sufficient energy to surpass the energy barrier and form products.

5. Which of the following chambers of the heart receives blood returning from the lungs during pulmonary circulation?

• A. left atrium
• B. right atrium
• C. left ventricle
• D. right ventricle

Correct answer: A

Rationale: The correct answer is A, the left atrium. During pulmonary circulation, oxygenated blood returns from the lungs to the heart and enters the left atrium through the pulmonary veins. The left atrium then contracts, pushing this oxygen-rich blood into the left ventricle. The left ventricle subsequently pumps this oxygenated blood out to the rest of the body through the aorta. Choices B, C, and D are incorrect because the right atrium receives deoxygenated blood from the body, the left ventricle receives oxygenated blood from the left atrium, and the right ventricle pumps deoxygenated blood to the lungs for oxygenation, respectively.

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