Nursing Elites

1. Neurotransmitters send chemical messages across the gap between one neuron and another through which of the following structures?

• A. Schwann cell
• B. ganglion
• C. synapse
• D. axon

Correct answer: C

Rationale: Neurotransmitters send chemical messages across the gap between one neuron and another through a structure called the synapse. The synapse is a specialized junction where the axon of one neuron meets the dendrite or cell body of another neuron. Neurotransmitters are released from the axon terminal of the presynaptic neuron and travel across the synaptic cleft to bind to receptors on the postsynaptic neuron, transmitting the signal between the two neurons. Choice A, Schwann cell, is incorrect as Schwann cells are responsible for producing myelin sheath around axons in the peripheral nervous system, not for transmitting neurotransmitters between neurons. Choice B, ganglion, is incorrect as ganglia are clusters of nerve cell bodies outside the central nervous system and do not directly participate in the transmission of chemical messages between neurons. Choice D, axon, is incorrect as the axon is a long, slender projection of a neuron that conducts electrical impulses away from the cell body and towards the axon terminals, where neurotransmitters are released into the synapse, but it is not the structure across which neurotransmitters travel to communicate between neurons.

2. What is the function of the pons?

• A. Center for emotion and motivation
• B. Control production of hormones
• C. Relay messages from the cortex to the cerebellum
• D. Responsible for involuntary actions like breathing

Correct answer: C

Rationale: The correct function of the pons is to relay messages from the cortex to the cerebellum. The pons acts as a bridge between different brain regions, facilitating communication and coordination of movements. Choices A, B, and D are incorrect. The pons is not the center for emotion and motivation, does not control hormone production, and is not primarily responsible for involuntary actions like breathing. Understanding the role of the pons in relaying messages between brain regions is crucial for comprehending its function in the central nervous system.

3. What is the name of the muscular ring that controls the passage of food from the esophagus to the stomach?

• A. Pyloric sphincter
• B. Cardiac sphincter
• C. Ileocecal valve
• D. Sphincter of Oddi

Correct answer: B

Rationale: The correct answer is the Cardiac sphincter (lower esophageal sphincter). It is situated at the junction of the esophagus and the stomach, controlling the passage of food into the stomach. The cardiac sphincter opens and closes to regulate the flow of food and prevent reflux. The pyloric sphincter, on the other hand, is located between the stomach and the small intestine, not the esophagus and stomach. The ileocecal valve is positioned between the small and large intestines, while the Sphincter of Oddi is found in the duodenum, not between the esophagus and stomach.

4. What are the moon-shaped white structures at the base of fingernails called?

• A. Lunulae
• B. Cuticle
• C. Hyponychium
• D. Matrix

Correct answer: A

Rationale: The correct answer is A: Lunulae. The moon-shaped white structures at the base of fingernails are known as lunulae. They are most prominent on the thumb and are situated at the base of the nail matrix. The lunula is the visible part of the nail matrix, which is responsible for generating new nail cells. Choice B, Cuticle, is incorrect as it refers to the thin layer of skin at the base of the nail plate. Choice C, Hyponychium, is incorrect as it is the skin that lies beneath the free edge of the nail. Choice D, Matrix, is incorrect as it is the area where the nail is formed, located under the cuticle.

5. What happens to the internal energy of a system when it performs work on its surroundings?

• A. It increases.
• B. It decreases.
• C. It remains the same.
• D. Insufficient information.

Correct answer: B

Rationale: When a system performs work on its surroundings, it loses energy in the form of work done. This results in a decrease in the internal energy of the system. Work done by the system is considered as negative work, leading to a decrease in internal energy. Therefore, the correct answer is that the internal energy decreases when a system performs work on its surroundings. Choice A is incorrect as the internal energy decreases, not increases. Choice C is incorrect because the internal energy changes due to the work done. Choice D is incorrect because the information provided is sufficient to determine the change in internal energy.

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