Nursing Elites

1. Electrons occupy specific energy levels around the nucleus, but not in fixed orbits. This concept is captured by the:

• A. Bohr model
• B. Quantum mechanical model
• C. Lewis structure
• D. Octet rule

Correct answer: B

Rationale: The correct answer is the Quantum mechanical model. Unlike the Bohr model with its defined electron paths, the quantum mechanical model uses probability distributions to describe electron locations within energy levels. Choice A, the Bohr model, describes fixed electron orbits, which is not in line with the concept of electron distribution in energy levels. Choices C and D, Lewis structure and Octet rule respectively, are not related to the description of electron distribution around the nucleus in energy levels, making them incorrect answers.

2. What is the primary function of the respiratory system?

• A. Maintain body temperature
• B. Deliver oxygen to the bloodstream and remove carbon dioxide
• C. Produce antibodies for the immune system
• D. Break down food molecules for energy

Correct answer: B

Rationale: The primary function of the respiratory system is to deliver oxygen to the bloodstream and remove carbon dioxide. This process occurs through breathing, where oxygen is inhaled into the lungs and then transferred to the bloodstream, while carbon dioxide is removed from the bloodstream and exhaled out of the body. Maintaining body temperature (A), producing antibodies for the immune system (C), and breaking down food molecules for energy (D) are functions of other systems in the body, not the respiratory system. Therefore, the correct answer is B.

3. What is the approximate composition of blood?

• A. 45% plasma, 55% formed elements
• B. 55% plasma, 45% formed elements
• C. 55% water, 45% blood cells
• D. 45% water, 55% plasma

Correct answer: B

Rationale: Blood is composed of approximately 55% plasma (mostly water with proteins, electrolytes, and nutrients) and 45% formed elements (red blood cells, white blood cells, and platelets). Choice B is the correct answer. Choice A is incorrect as it reverses the percentages. Choice C is incorrect because it incorrectly states that blood cells make up 45% of blood, while they are part of the formed elements along with platelets. Choice D is incorrect as it suggests that water makes up 45% of blood, which is not accurate.

4. What is the purpose of the periosteum, the tough outer layer of bone?

• A. Produces red blood cells
• B. Provides protection and nourishment to bone
• C. Forms the joint surface
• D. Stores minerals

Correct answer: B

Rationale: The periosteum, the tough outer layer of bone, serves the purpose of providing protection to the bone and nourishing it through the blood vessels it contains. It acts as a protective layer for the bone structures. Choices A, C, and D are incorrect because the periosteum does not produce red blood cells (which is the function of bone marrow), form joint surfaces (which is typically the role of articular cartilage), or store minerals (which is primarily done by bone tissue itself and not the periosteum).

5. How does the developing fetus primarily eliminate metabolic wastes?

• A. The developing fetus does not produce metabolic wastes.
• B. Fetal waste is excreted as feces, which pass into the mother's anus.
• C. Fetal waste is passed down the umbilical cord to the mother's circulatory system.
• D. Fetal waste is passed down the umbilical cord and leaves the mother's body via the vagina.

Correct answer: C

Rationale: Metabolic wastes produced by the developing fetus are eliminated primarily by being passed down the umbilical cord to the mother's circulatory system. Once in the mother's blood, these wastes are then filtered and excreted by the mother's kidneys. Choice A is incorrect because the developing fetus does produce metabolic wastes. Choice B is incorrect as fetal waste does not pass into the mother's anus. Choice D is incorrect as fetal waste does not leave the mother's body via the vagina.

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