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. The order of operations (PEMDAS) dictates the sequence for evaluating mathematical expressions. If a = 2 and b = -3, what is the value of 3a^2 - 2ab + b^2?

• A. -3
• B. 0
• C. 33
• D. 15

Correct answer: C

Rationale: Following PEMDAS (Parentheses, Exponents, Multiplication and Division from left to right, Addition and Subtraction from left to right), we start with exponents: 3(2^2) - 2ab + b^2. Then, multiply: 3(4) - 2ab + b^2. Next, perform the multiplication/division from left to right: 12 - 2ab + b^2. Finally, add/subtract from left to right: 12 + (-2)(2)(-3) + (-3)^2. Evaluate the remaining terms: 12 + 12 + 9. The answer is 33.

3. Which respiratory structure is responsible for vocalization and sound production?

• A. Trachea
• B. Larynx
• C. Bronchi
• D. Alveoli

Correct answer: B

Rationale: The correct answer is B: Larynx. The larynx, also known as the voice box, is the respiratory structure responsible for vocalization and sound production. It contains the vocal cords, which vibrate as air passes through, producing sound. The trachea (A) is the windpipe that carries air to and from the lungs. The bronchi (C) are the main airways that branch off from the trachea into the lungs. The alveoli (D) are tiny air sacs in the lungs where gas exchange occurs, but they are not directly involved in vocalization.

4. Square: A garden bed has a side length of 8 meters. What is its perimeter?

• A. 16m
• B. 24m
• C. 32m
• D. 64m

Correct answer: D

Rationale: Since all sides are equal, multiply the side length by 4: perimeter = 4 * side length = 4 * 8m = 32m.

5. Which hormone, produced by the thyroid gland, regulates calcium levels in the blood by enhancing calcium absorption in the intestines and reducing calcium loss in the kidneys?

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

Correct answer: a

Rationale: The correct answer is A: Calcitonin. Calcitonin is a hormone produced by the thyroid gland that plays a crucial role in regulating calcium levels in the blood. It works by enhancing calcium absorption in the intestines and reducing calcium loss in the kidneys. This helps to maintain the proper balance of calcium in the body. Parathyroid hormone (PTH) works in the opposite way, increasing calcium levels in the blood when they are low. Thyroxine is a hormone produced by the thyroid gland that regulates metabolism and growth, not calcium levels. Insulin is a hormone produced by the pancreas that regulates blood sugar levels, not calcium levels. Therefore, the correct hormone in this case is Calcitonin.

6. Which of the following is NOT a recognized mode of natural selection?

• A. Directional selection (favoring one extreme trait value on a spectrum)
• B. Disruptive selection (favoring both extreme trait values on a spectrum)
• C. Stabilizing selection (favoring the average trait value on a spectrum)
• D. Sexual selection (selection based on mate choice that influences reproductive success)

Correct answer: D

Rationale: Rationale: A) Directional selection is a recognized mode of natural selection where one extreme trait value on a spectrum is favored over others. This can lead to a shift in the average trait value over time. B) Disruptive selection is a recognized mode of natural selection where both extreme trait values on a spectrum are favored over the average trait value. This can lead to the population splitting into two distinct groups. C) Stabilizing selection is a recognized mode of natural selection where the average trait value on a spectrum is favored over extreme values. This can lead to a reduction in genetic diversity within a population. D) Sexual selection is not a mode of natural selection in the traditional sense, as it involves mate choice and competition for mates rather than direct selection pressure on traits that affect survival and reproduction in the environment. Sexual selection can lead to the evolution of traits that enhance an individual's ability to attract

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