Nursing Elites

1. During embryonic development, most vertebrates exhibit structures called pharyngeal pouches. These pouches eventually develop into different structures in various vertebrate groups, such as the human jaw and inner ear. Pharyngeal pouches are an example of:

• A. Analogous structures with different evolutionary origins but similar functions
• B. Homologous structures with a common evolutionary origin but diverse functions
• C. Vestigial structures that no longer serve a vital function in some organisms
• D. Atavisms, the reappearance of a trait absent in recent generations

Correct answer: B

Rationale: Pharyngeal pouches in vertebrates are an example of homologous structures because they share a common evolutionary origin. Despite developing into different structures in various vertebrate groups, such as the jaw and inner ear in humans, these structures originated from the same ancestral feature. This concept of homology highlights the evolutionary relationship between different species and how structures can be modified over time to serve different functions while retaining a common origin. Choice A is incorrect because analogous structures have similar functions but different evolutionary origins, which does not apply to pharyngeal pouches. Choice C is incorrect as vestigial structures are remnants of features that were functional in ancestors but have reduced or lost their original function, which is not the case for pharyngeal pouches. Choice D is incorrect because atavisms refer to the reappearance of traits absent in recent generations, which is not the characteristic of pharyngeal pouches.

2. Which hormone, produced by the adrenal glands, helps regulate the body's response to stress, including increasing blood pressure and suppressing the immune system?

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

Correct answer: C

Rationale: Cortisol is the correct answer. It is the hormone produced by the adrenal glands that helps regulate the body's response to stress. Cortisol plays a crucial role in increasing blood pressure and suppressing the immune system during stressful situations. Aldosterone, another hormone from the adrenal glands, primarily regulates salt and water balance in the body, not the stress response. Epinephrine, also known as adrenaline, is produced by the adrenal glands in response to stress, but its effects are more immediate and short-lived compared to cortisol. Insulin, produced by the pancreas, regulates blood sugar levels and is not directly involved in the body's response to stress.

3. Which term describes the ability of a substance to conduct electricity?

• A. Reactivity
• B. Density
• C. Conductivity
• D. Viscosity

Correct answer: C

Rationale: Conductivity is the correct term used to describe the ability of a substance to conduct electricity. Reactivity is the measure of a substance's tendency to undergo chemical reactions. Density refers to the mass per unit volume of a substance, while viscosity is a measure of a fluid's resistance to flow. In the context of conducting electricity, conductivity is the most appropriate term as it directly relates to the substance's electrical conductive properties.

4. Which part of the nervous system controls the 'fight or flight' response?

• A. Central nervous system
• B. Peripheral nervous system
• C. Autonomic nervous system
• D. Sympathetic nervous system

Correct answer: D

Rationale: The correct answer is the sympathetic nervous system. It controls the 'fight or flight' response by preparing the body for stressful situations. The central nervous system (Choice A) consists of the brain and spinal cord but does not directly control the 'fight or flight' response. The peripheral nervous system (Choice B) includes nerves outside the brain and spinal cord, while the autonomic nervous system (Choice C) regulates involuntary bodily functions but is not specific to the 'fight or flight' response.

5. What describes a cell’s reaction to being placed in a hypertonic solution?

• A. The cell will shrink as water is pulled out of the cell to equalize the concentrations inside and outside of the cell.
• B. The cell will swell as water is pulled into the cell to equalize the concentrations inside and outside of the cell.
• C. The cell will remain the same size since the concentrations inside and outside the cell are equal to begin with.
• D. The pH inside the cell will drop in order to equalize the pH inside and outside the cell.

Correct answer: A

Rationale: A cell placed in a hypertonic solution has a higher solute concentration outside the cell compared to inside. This creates a concentration gradient that causes water to move out of the cell through osmosis to equalize the concentrations on both sides. As a result, the cell will shrink or undergo plasmolysis, as water is pulled out of the cell. Choice B is incorrect because a hypertonic solution causes water to move out of the cell, leading to shrinkage rather than swelling. Choice C is incorrect as a hypertonic solution results in a concentration gradient that leads to water leaving the cell, causing it to shrink. Choice D is incorrect because pH is not directly affected by being placed in a hypertonic solution; the change in solute concentration primarily impacts water movement.

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