Nursing Elites

1. Which of the following best describes the function of the pericardium?

• A. Regulating blood flow through valves within the heart.
• B. Acting as a protective sac surrounding the heart.
• C. Generating the electrical impulses for heart contractions.
• D. Transmitting electrical signals between the atria and ventricles.

Correct answer: B

Rationale: The pericardium is a double-layered sac that surrounds and protects the heart. Its main functions include preventing overfilling of the heart, providing a physical barrier against infection and inflammation, and reducing friction between the heart and surrounding structures. Choices A, C, and D do not accurately describe the function of the pericardium. Option B is the correct answer as it aligns with the protective and supportive role of the pericardium, distinguishing it from the functions attributed to choices A, C, and D.

2. When animals eat, insulin is released from the pancreas, stimulating glucose uptake by the liver. When glucose levels drop, the pancreas reduces insulin release. This is an example of which mechanism for maintaining homeostasis?

• A. Negative feedback.
• B. Positive feedback.
• C. Stress response.
• D. Parasympathetic regulation.

Correct answer: A

Rationale: This mechanism is an example of negative feedback. Negative feedback systems work to counteract changes in the body and maintain a stable internal environment (homeostasis). In this case, the release of insulin in response to high glucose levels is followed by a reduction in insulin release when glucose levels drop. This response helps regulate glucose levels and return them to a normal range, demonstrating the characteristic of negative feedback where the body's response opposes the initial stimulus to maintain equilibrium. Positive feedback would amplify the initial change rather than counteract it, so it is not the correct choice. Stress response and parasympathetic regulation are not directly involved in this glucose regulation process, making them incorrect choices.

3. What are energy levels and orbitals?

• A. Energy levels are the paths that electrons travel around the nucleus of an atom, and orbitals are the regions where electrons are most likely to be found.
• B. Energy levels are the regions where electrons are most likely to be found, and orbitals are the paths that electrons travel around the nucleus of an atom.
• C. Energy levels are the same as orbitals.
• D. Energy levels and orbitals do not exist.

Correct answer: A

Rationale: Energy levels refer to the specific energies that electrons in an atom can have, while orbitals are the regions within an atom where electrons are most likely to be found. Electrons do not travel in fixed paths around the nucleus like planets around the sun, as suggested in option B. Option C is incorrect because energy levels and orbitals are distinct concepts in atomic structure. Option D is incorrect as energy levels and orbitals are fundamental concepts in understanding the behavior of electrons in atoms.

4. Which of the following is an example of a tissue?

• A. chloroplasts
• B. liver
• C. mammal
• D. hamstring

Correct answer: B

Rationale: The correct answer is 'B: liver.' The liver is an example of a tissue. Tissues are groups of cells that work together to perform specific functions in the body. The liver is made up of different types of cells that work together to carry out various essential functions, such as detoxification, metabolism, and storage of nutrients. Option A (chloroplasts) refers to organelles, not tissues. Option D (hamstring) is a muscle, not a tissue. Option C (mammal) represents a higher level of organization than tissues, as it refers to a classification of organisms, not a specific tissue type.

5. What property of a substance refers to its ability to undergo a chemical change and form new substances?

• A. Density
• B. Mass
• C. Reactivity
• D. Volume

Correct answer: C

Rationale: Reactivity is the property of a substance that describes its ability to undergo a chemical change and form new substances. Density (A), mass (B), and volume (D) are physical properties of a substance and do not directly relate to its ability to undergo chemical changes. Density is the measure of how much mass is contained in a given volume, mass is the amount of matter in an object, and volume is the amount of space an object occupies. Therefore, reactivity (C) is the correct answer as it specifically addresses the substance's ability to undergo chemical changes.

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