Nursing Elites

1. What is the formula to calculate gravitational potential energy near the Earth's surface?

• A. Potential Energy = Mass × Acceleration
• B. Potential Energy = Force × Distance
• C. Potential Energy = Mass × Height × Gravity
• D. Potential Energy = Mass × Acceleration due to gravity × Height

Correct answer: D

Rationale: The correct formula to calculate gravitational potential energy near the Earth's surface is Potential Energy = Mass × Acceleration due to gravity × Height. This formula considers the mass of the object, the specific acceleration due to gravity near the Earth's surface (approximately 9.81 m/s^2), and the vertical distance from the reference point. Choice A is incorrect as it does not include height in the formula. Choice B is incorrect as it involves force instead of acceleration due to gravity. Choice C is incorrect as it multiplies mass, height, and gravity, missing the actual acceleration due to gravity term.

2. What is the most powerful stimulus for breathing in a healthy person?

• A. Acidosis
• B. Alkalosis
• C. Increase in CO2
• D. Loss of O2

Correct answer: C

Rationale: The correct answer is an increase in CO2. In a healthy individual, the primary drive to breathe is regulated by the levels of carbon dioxide (CO2) in the blood. When CO2 levels increase, it triggers the body to increase the rate and depth of breathing to eliminate excess CO2 and restore the balance. This response is more powerful than other stimuli such as acidosis, alkalosis, or loss of oxygen. While acidosis and alkalosis can affect breathing, an increase in CO2 has a more direct and immediate impact. Loss of oxygen (hypoxia) is a potent stimulus, but the body's response to increased CO2 levels is generally more pronounced and immediate in healthy individuals.

3. What are groups of cells that perform the same function called?

• A. tissues
• B. plastids
• C. organs
• D. molecules

Correct answer: A

Rationale: Groups of cells that perform the same function are called tissues. Tissues are composed of a group of similar cells working together to carry out specific functions within an organism. Each type of tissue has a specialized structure that enables it to perform its specific role effectively. Plastids are cell organelles found in plants responsible for functions like photosynthesis and storage, not groups of cells. Organs are composed of different types of tissues working together. Molecules are made up of atoms and are not groups of cells.

4. What generates action potentials, the all-or-nothing electrical signals traveling along neurons?

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

Correct answer: B

Rationale: Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of sodium and potassium ions across the neuronal membrane. This movement creates changes in the membrane potential, leading to the propagation of the electrical signal along the neuron. Glucose is a source of energy for neurons but is not directly involved in generating action potentials. Neurotransmitters are involved in communication between neurons but do not directly generate action potentials. Myelin is a fatty substance that insulates and speeds up the conduction of action potentials but does not generate them.

5. Which cells myelinate neurons in the PNS?

• A. Oligodendrocytes
• B. Astrocytes
• C. Schwann cells
• D. Microglia

Correct answer: C

Rationale: Schwann cells are the glial cells responsible for myelinating neurons in the peripheral nervous system (PNS). They form the myelin sheath around axons, which helps in the conduction of electrical impulses. Oligodendrocytes, on the other hand, myelinate neurons in the central nervous system (CNS). Astrocytes primarily provide support for neuronal function by regulating the chemical environment around neurons and maintaining the blood-brain barrier. Microglia are part of the immune response in the CNS, where they act as the resident macrophages, playing a role in immune surveillance and response to injury or disease. Therefore, the correct answer is Schwann cells (Choice C) as they specifically myelinate neurons in the PNS, differentiating them from the other cell types mentioned in the choices.

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