Which statement correctly relates to thirst mechanism in dehydration?

Which statement correctly relates to thirst mechanism in dehydration?

• A. It is triggered when the brain detects increased osmotic pressure in blood plasma
• B. It is triggered when electrical storms in the brain occur
• C. It is triggered only by salt intake
• D. It is triggered by intense exercise regardless of hydration

Answer: (A)

Thirst is driven by osmotic cues. When you become dehydrated, the concentration of solutes in the blood rises, increasing plasma osmolality. Osmoreceptors in the hypothalamus detect this change and trigger the sensation of thirst to prompt water intake, while also signaling antidiuretic hormone release to conserve water. This osmotic mechanism explains why dehydration activates thirst. The other statements don’t fit: thirst isn’t caused by random electrical activity in the brain, it isn’t triggered only by salt intake, and although intense exercise can accompany fluid loss, thirst responds to osmotic and volume signals rather than occurring irrespective of hydration status.

Thirst is driven by osmotic cues. When you become dehydrated, the concentration of solutes in the blood rises, increasing plasma osmolality. Osmoreceptors in the hypothalamus detect this change and trigger the sensation of thirst to prompt water intake, while also signaling antidiuretic hormone release to conserve water. This osmotic mechanism explains why dehydration activates thirst. The other statements don’t fit: thirst isn’t caused by random electrical activity in the brain, it isn’t triggered only by salt intake, and although intense exercise can accompany fluid loss, thirst responds to osmotic and volume signals rather than occurring irrespective of hydration status.