52 yo man is brought to er 30min after the onset of chest pain and shortness of breath. he had played tennis all day and he does not remember how much fluid he had consumed. his temperature is 36.7 oc, pulse 122min, respirations 28min and bp 90/50 mmhg. pe shows dry skin and decreased capillary refill. an ecg and evaluation of cardiac enzymes show no abnormalities. which of the following findings in the nephron best describes the tubular osmolarity, compared with serum in this patient?
pt //macula densa //medullary collection ductiso, hypo,