Nursing Elites

1. What is the primary function of the myelin sheath that surrounds some axons in the nervous system?

• A. To initiate nerve impulses
• B. To transmit sensory information
• C. To speed up the transmission of nerve impulses
• D. To connect neurons at synapses

Correct answer: C

Rationale: The primary function of the myelin sheath is to speed up the transmission of nerve impulses. The myelin sheath acts as an insulating layer around the axon, allowing for faster conduction of electrical impulses along the nerve fiber. This insulation prevents the electrical signal from dissipating or 'leaking' out, which helps in the rapid and efficient transmission of nerve impulses along the axon. Choice A is incorrect because the myelin sheath does not initiate nerve impulses; it helps in conducting them. Choice B is incorrect as the myelin sheath's main role is not in transmitting sensory information but rather in facilitating the transmission of nerve impulses. Choice D is incorrect because the myelin sheath's function is not to connect neurons at synapses; instead, it is primarily involved in enhancing the speed of nerve impulse transmission.

2. Adipose tissue, also known as fat, serves multiple functions. Which of these is NOT a function of adipose tissue?

• A. Insulation
• B. Energy storage
• C. Hormone production
• D. Muscle movement

Correct answer: D

Rationale: Adipose tissue serves multiple functions in the body, including insulation to regulate body temperature, energy storage in the form of triglycerides, and hormone production such as leptin and adiponectin. Adipose tissue does not directly participate in muscle movement. Muscle movement is primarily carried out by skeletal muscle tissue, which is responsible for voluntary movements and locomotion. Therefore, the correct answer is D, as adipose tissue is not involved in muscle movement.

3. Which of the following neurotransmitters slows down the activity of neurons, preventing them from becoming overexcited?

• A. Acetylcholine
• B. Dopamine
• C. GABA
• D. Serotonin

Correct answer: C

Rationale: The correct answer is C: GABA (gamma-aminobutyric acid). GABA acts as an inhibitory neurotransmitter that reduces neuronal activity, thus preventing overexcitation. Acetylcholine (choice A) is involved in muscle control and cognitive function, but it is not primarily responsible for slowing down neuronal activity. Dopamine (choice B) plays a role in reward-motivated behavior and motor control, rather than inhibiting neuronal firing. Serotonin (choice D) is involved in mood regulation, sleep, and appetite but does not primarily slow down neuronal activity to prevent overexcitation.

4. What is the breakdown product of ATP (adenosine triphosphate) that provides energy for muscle contraction?

• A. Glucose
• B. Creatine phosphate
• C. ADP (adenosine diphosphate)
• D. Lactic acid

Correct answer: C

Rationale: ADP (adenosine diphosphate) is the correct breakdown product of ATP that provides energy for muscle contraction. When ATP is hydrolyzed to ADP, energy is released and utilized by the muscles for various cellular processes, including muscle contraction. Glucose serves as an energy source but is not the direct breakdown product of ATP for muscle contraction. Creatine phosphate plays a role in energy storage and transfer, but it is not the immediate breakdown product of ATP. Lactic acid is produced during anaerobic metabolism and is not the direct provider of energy for muscle contraction.

5. What is the primary factor that determines whether a solute will dissolve in a solvent?

• A. Temperature
• B. Pressure
• C. Molecular structure
• D. Particle size

Correct answer: C

Rationale: The primary factor that determines whether a solute will dissolve in a solvent is the molecular structure. The compatibility of the solute's molecules with the solvent's molecules is crucial for dissolution to occur. While temperature, pressure, and particle size can influence the rate of dissolution, they are not the primary factors determining solubility. Molecular structure plays a key role in determining if a solute will form favorable interactions with the solvent, which is essential for dissolution to take place effectively. Temperature can affect solubility by changing the kinetic energy of molecules, pressure typically has a minor effect on solubility except for gases, and particle size influences the rate of dissolution by increasing surface area, but none of these factors are as fundamentally important as molecular structure in determining solubility.

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