Nursing Elites

1. Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of:

• A. Glucose
• B. Sodium and potassium ions
• C. Neurotransmitters
• D. Myelin

Correct answer: B

Rationale: The correct answer is B: Sodium and potassium ions. Action potentials are generated by the movement of sodium and potassium ions across the neuronal membrane. During depolarization, sodium ions rush into the cell, causing a change in electrical charge. This influx of positive ions triggers the opening of voltage-gated potassium channels, allowing potassium ions to exit the cell during repolarization. Glucose is a source of energy for cells but does not directly generate action potentials. Neurotransmitters are chemical messengers released at synapses, while myelin is a fatty substance that insulates axons, speeding up the conduction of action potentials but not directly generating them.

2. A child's toy block is a cube with side lengths of 5cm. What is its total surface area?

• A. 25 sq cm
• B. 50 sq cm
• C. 125 sq
• D. 150 sq cm

Correct answer: D

Rationale: Use the formula for surface area of a cube: 6 * (side length)^2 = 6 * (5cm)^2 = 125 sq cm.

3. The involuntary, rhythmic contractions of the heart muscle are controlled by a specialized group of cells located in the:

• A. Lungs
• B. Brain
• C. Spinal cord
• D. Sinoatrial node (located within the heart)

Correct answer: D

Rationale: The correct answer is D: Sinoatrial node (located within the heart). The sinoatrial node, also known as the heart's natural pacemaker, is a cluster of specialized cells within the heart that controls the heart rate by initiating the electrical impulses that regulate the heart's contractions. The lungs (A), brain (B), and spinal cord (C) do not directly control the rhythmic contractions of the heart muscle. Therefore, the sinoatrial node is the specific anatomical location responsible for regulating the heart's rhythmic contractions, making it the correct answer.

4. Which property of a substance refers to its ability to be hammered or pressed into thin sheets without breaking?

• A. Malleability
• B. Ductility
• C. Viscosity
• D. Conductivity

Correct answer: a

Rationale: Malleability is the property that describes a substance's ability to be hammered or pressed into thin sheets without breaking.

5. Tissues are groups of cells with similar:

• A. Appearance only
• B. Function and structure
• C. Location only
• D. Age only

Correct answer: B

Rationale: The correct answer is B: 'Function and structure.' Tissues are groups of cells that work together to perform a specific function in the body. These cells have both similar functions, such as carrying out a specific task like contracting in muscle tissue, and similar structures, such as having similar shapes or types of organelles. This allows them to work together efficiently and effectively. Choices A, C, and D are incorrect because tissues are defined by more than just appearance, location, or age; they are primarily characterized by their shared function and structure.

6. A salt solution that conducts electricity well is most likely

• A. A saturated solution
• B. A concentrated solution of a strong electrolyte
• C. A dilute solution of a weak acid
• D. A mixture of a neutral compound and water

Correct answer: B

Rationale: The correct answer is B: "A concentrated solution of a strong electrolyte." Strong electrolytes completely dissociate into ions in solution, thereby increasing the conductivity of the solution. Concentrated solutions have a higher amount of dissolved solute particles, which leads to more ions available for conducting electricity. In contrast, saturated solutions may contain undissolved solute, limiting the number of ions in solution. Dilute solutions have fewer ions and weak acids only partially dissociate, reducing conductivity. A neutral compound and water do not provide ions for conducting electricity. Therefore, a concentrated solution of a strong electrolyte is most likely to conduct electricity well due to the high concentration of ions present.

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