During a mountain climb, a 23-year-old hiker loses a foothold and falls several feet. He is not seriously injured, but he does lose his backpack. He walks for 8 hours in the heat without water, and by the time he reaches a shelter, he is extremely thirsty. Which of the following nephron segments' fluid is most likely to be hypoosmotic in this individual?

Question

Quizplus · Accepted Answer

Eductional Objective: Dehydration (e.g., hypotension, high plasma osmolarity) raises circulating levels of antidiuretic hormone, increasing the collecting duct's water permeability and allowing the production of highly concentrated urine. Tubular fluid osmolarity will be lowest at the distal convoluted tubule's beginning in the dehydrated state (ie, terminus of loop of Henle).

During a Mountain Climb, a 23-Year-Old Hiker Loses a Foothold