Medical Quiz 1

Endocrine system quiz. Disclaimer: translated from spanish to english

Prompt

What happens to ADH concentration when plasma osmolality falls below normal? A. It is converted to oxytocin B. It increases to reduce water excretion C. It remains the same D. It is suppressed to reduce water reabsorption Answer only with the option chosen

Answer guidance

The answer is D

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D. It is suppressed to reduce water reabsorption

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Alibaba

Qwen3 235B A22B (Non-reasoning)

D. It is suppressed to reduce water reabsorption

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## Step 2: Recall how plasma osmolality affects ADH secretion
When plasma osmolality increases (becomes more concentrated), it indicates less water in the blood relative to solutes, and ADH secretion is stimulated to promote water retention. Conversely, when plasma osmolality decreases (becomes less concentrated), indicating more water relative to solutes, ADH secretion is suppressed.

## Step 3: Relate the given condition to ADH concentration
The given condition is that plasma osmolality falls below normal. This means the blood is more diluted than normal, indicating there is relatively more water in the blood.

## Step 4: Apply the understanding of ADH regulation to the given condition
Since plasma osmolality is below normal, the body needs to reduce water reabsorption to allow more water to be excreted and thus concentrate the blood back to normal osmolality. ADH promotes water reabsorption. So, when osmolality is low, ADH secretion should be reduced to decrease water reabsorption.

## Step 5: Choose the correct response based on the understanding of ADH and osmolality regulation
Given that ADH secretion is suppressed when plasma osmolality is low to reduce water reabsorption and thus help normalize osmolality, the correct action is that ADH concentration is suppressed.

The best answer is D.

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DeepSeek

DeepSeek R1 0528 (May '25)

When plasma osmolality falls below normal, the body responds by suppressing ADH (antidiuretic hormone) secretion. This occurs because lower plasma osmolality indicates overhydration or dilution of the blood. Suppressing ADH reduces water reabsorption in the kidneys, leading to increased water excretion (diuresis) to restore normal osmolality. 

Option A is incorrect because ADH is not converted to oxytocin; they are distinct hormones.  
Option B is incorrect because ADH increases to promote water reabsorption and reduce excretion, which is not appropriate when osmolality is low.  
Option C is incorrect because ADH concentration does not remain the same; it changes in response to osmolality.  
Option D correctly states that ADH is suppressed to reduce water reabsorption.  

Answer: D

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Alibaba

Qwen3 8B (Non-reasoning)

D. It is suppressed to reduce water reabsorption

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Anthropic

Claude 4 Sonnet (Non-reasoning)

D. It is suppressed to reduce water reabsorption

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xAI

Grok 3 mini Reasoning (high)

D. It is suppressed to reduce water reabsorption

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## Step 1: Understand the role of ADH in relation to plasma osmolality ADH (Antidiuretic Hormone) plays a crucial role in regulating the amount of water in the body by acting on the kidneys to increase water reabsorption. Its secretion is influenced by the osmolality of the plasma. ## Step 2: Recall how plasma osmolality affects ADH secretion When plasma osmolality increases (becomes more concentrated), it indicates less water in the blood relative to solutes, and ADH secretion is stimulated to promote water retention. Conversely, when plasma osmolality decreases (becomes less concentrated), indicating more water relative to solutes, ADH secretion is suppressed. ## Step 3: Relate the given condition to ADH concentration The given condition is that plasma osmolality falls below normal. This means the blood is more diluted than normal, indicating there is relatively more water in the blood. ## Step 4: Apply the understanding of ADH regulation to the given condition Since plasma osmolality is below normal, the body needs to reduce water reabsorption to allow more water to be excreted and thus concentrate the blood back to normal osmolality. ADH promotes water reabsorption. So, when osmolality is low, ADH secretion should be reduced to decrease water reabsorption. ## Step 5: Choose the correct response based on the understanding of ADH and osmolality regulation Given that ADH secretion is suppressed when plasma osmolality is low to reduce water reabsorption and thus help normalize osmolality, the correct action is that ADH concentration is suppressed. The best answer is D.

When plasma osmolality falls below normal, the body responds by suppressing ADH (antidiuretic hormone) secretion. This occurs because lower plasma osmolality indicates overhydration or dilution of the blood. Suppressing ADH reduces water reabsorption in the kidneys, leading to increased water excretion (diuresis) to restore normal osmolality. Option A is incorrect because ADH is not converted to oxytocin; they are distinct hormones. Option B is incorrect because ADH increases to promote water reabsorption and reduce excretion, which is not appropriate when osmolality is low. Option C is incorrect because ADH concentration does not remain the same; it changes in response to osmolality. Option D correctly states that ADH is suppressed to reduce water reabsorption. Answer: D