Nursing Elites

1. A keystone species plays a critical role in an ecosystem because its removal would:

• A. Lead to a decrease in competition among other species
• B. Cause a slight increase in primary productivity
• C. Have a minimal impact on the overall ecosystem structure
• D. Disrupt the food web and cause cascading effects on other populations

Correct answer: D

Rationale: Rationale: Keystone species are species that have a disproportionately large effect on their environment relative to their abundance. They play a critical role in maintaining the structure and function of an ecosystem. If a keystone species is removed from an ecosystem, it can disrupt the food web by causing imbalances in predator-prey relationships. This disruption can lead to cascading effects on other populations within the ecosystem, potentially causing population declines or even extinctions. Therefore, the removal of a keystone species would have significant impacts on the overall ecosystem structure, making option D the correct answer.

2. What literary device is used in the phrase "the lion's roar thundered across the savanna"?

• A. Simile
• B. Metaphor
• C. Hyperbole
• D. Personification

Correct answer: A

Rationale: Option A compares the roar to thunder using "like" or "as," making it a simile.

3. What is the neurotransmitter involved in muscle movement?

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

Correct answer: B

Rationale: The correct answer is B: Acetylcholine. Acetylcholine is the neurotransmitter involved in muscle movement. It is released by motor neurons at the neuromuscular junction to stimulate muscle contraction. Dopamine is involved in reward and pleasure pathways in the brain, serotonin plays a role in mood regulation, and GABA is an inhibitory neurotransmitter that helps to reduce neural activity. Understanding the specific roles of neurotransmitters is crucial in grasping their functions in the nervous system.

4. The primary function of the atrioventricular (AV) node within the heart is to:

• A. Generate the electrical impulse for contraction (pacemaker function)
• B. Transmit the electrical impulse from atria to ventricles, regulating the timing of contraction.
• C. Increase blood pressure within the ventricles during systole.
• D. Separate oxygenated and deoxygenated blood flow in the heart.

Correct answer: B

Rationale: The correct answer is B: "Transmit the electrical impulse from atria to ventricles, regulating the timing of contraction." The AV node acts as a gateway between the atria and ventricles, ensuring a coordinated and sequential contraction of the heart chambers. It delays the conduction of electrical impulses to allow the atria to fully contract before the ventricles contract, facilitating efficient blood pumping. Options A, C, and D are incorrect because the primary role of the AV node is not to generate electrical impulses, increase blood pressure, or separate blood flow based on oxygenation status. Understanding the AV node's function is crucial in comprehending the heart's electrical conduction system.

5. Dendrites are finger-like extensions found on

• A. Muscle cells
• B. Connective tissue cells
• C. Neurons
• D. Epithelial cells

Correct answer: C

Rationale: Dendrites are the primary sites for receiving signals in a neuron. They are specialized extensions that branch out from the cell body of a neuron to receive incoming information from other neurons. These finger-like projections play a crucial role in transmitting electrical impulses and communication within the nervous system. Muscle cells, connective tissue cells, and epithelial cells do not have dendrites as they are not involved in neuronal communication.

6. The inability of the kidneys to effectively filter waste products from the blood is called:

• A. Dehydration
• B. Kidney failure
• C. Incontinence
• D. Nephritis

Correct answer: B

Rationale: The correct answer is B: "Kidney failure." Kidney failure refers to the inability of the kidneys to effectively filter waste products from the blood, leading to a buildup of toxins in the body. Dehydration, option A, is the state of lacking adequate fluid in the body and is not specifically related to kidney function. Incontinence, option C, is the loss of bladder control and is unrelated to kidney filtration function. Nephritis, option D, specifically refers to inflammation of the kidneys and may not always result in complete kidney failure. Therefore, the most appropriate answer for the described scenario is B.

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