Nursing Elites

1. Which energy transformation occurs when a guitar string vibrates to produce sound?

• A. Mechanical energy to thermal energy
• B. Kinetic energy to potential energy
• C. Electrical energy to sound energy
• D. Potential energy to kinetic energy

Correct answer: c

Rationale: The electrical energy in the guitar's amplifier is converted into sound energy when the string vibrates.

2. 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.

3. Which type of cell is responsible for carrying oxygen throughout the body?

• A. Nerve cell
• B. Muscle cell
• C. Skin cell
• D. Red blood cell

Correct answer: D

Rationale: The correct answer is D: Red blood cell. Red blood cells, also known as erythrocytes, are responsible for carrying oxygen throughout the body. They contain hemoglobin, a protein that binds to oxygen in the lungs and transports it to tissues and organs. Nerve cells (option A) transmit electrical signals, muscle cells (option B) are involved in movement, and skin cells (option C) form the outer layer of the skin and provide protection.

4. Which property of a substance measures the amount of matter per unit volume?

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

Correct answer: a

Rationale: Density is the property that measures the amount of matter (mass) per unit volume of a substance. It is calculated as mass divided by volume.

5. During which phase of the cardiac cycle do the atria contract, pushing blood into the ventricles?

• A. Atrial diastole
• B. Ventricular systole
• C. Atrial systole
• D. Ventricular diastole

Correct answer: C

Rationale: The correct answer is C: Atrial systole. During the cardiac cycle, the atria contract during atrial systole, pushing blood into the ventricles. This phase occurs after atrial diastole when the atria fill with blood. Ventricular diastole (option D) is when the ventricles relax and fill with blood, preparing for ventricular systole (option B), which is when the ventricles contract to pump blood out of the heart. Atrial systole is crucial for ensuring efficient filling of the ventricles before they contract, making it a key phase in the cardiac cycle.

6. Which hormone, produced by the adrenal glands, plays a crucial role in the body's response to stress, including the regulation of salt and water balance?

• A. Aldosterone
• B. Epinephrine
• C. Cortisol
• D. Insulin

Correct answer: A

Rationale: The correct answer is A: Aldosterone. Aldosterone is a hormone produced by the adrenal glands that plays a crucial role in the body's response to stress by regulating salt and water balance. It acts on the kidneys to increase the reabsorption of sodium and water, helping to maintain blood pressure and electrolyte balance during times of stress. Epinephrine and cortisol are also stress hormones produced by the adrenal glands, but they have different functions. Epinephrine is involved in the fight-or-flight response, while cortisol helps regulate metabolism and immune function. Insulin, produced by the pancreas, is involved in glucose metabolism and not directly related to the body's stress response. Therefore, aldosterone is the most appropriate hormone in this context.

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