An elderly patient complains of muscle weakness and lethargy. A urine specimen reveals a Na+ concentration of 600 mmol/L and an osmolarity of 1200 mOsm/L. Additional laboratory tests provide the following information: plasma Na+ concentration = 167 mmol/L, plasma renin activity = 4 ng angiotensin I/ml/hr (normal = 1), plasma antidiuretic hormone (ADH) = 60 pg/ml (normal = 3 pg/ml), and plasma aldosterone = 15 ng/dL (normal = 6 ng/dL). Which of the following is the most likely reason for this patient’s hypernatremia?

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#Question id: 12700

#Unit 7. System Physiology – Animal

A young man is found comatose, having taking an unknown number of sleeping pills an unknown time before. An arterial blood sample yields the following values: pH = 7.02, HCO3− = 14 mEq/L, and PCO2 = 68 mm Hg. This patient’s acid–base status is most accurately described as

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#Question id: 12699

#Unit 7. System Physiology – Animal

The following test results were obtained: urine flow rate = 2.0 ml/min; urine inulin concentration = 60 mg/ml; plasma inulin concentration = 2 mg/ml; urine potassium concentration = 20 μmol/ml; plasma potassium concentration = 4.0 μmol/ml; urine osmolarity = 150 mOsm/L; and plasma osmolarity = 300 mOsm/L. What is the free water clearance rate?

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#Question id: 12698

#Unit 7. System Physiology – Animal

The following test results were obtained: urine flow rate = 2.0 ml/min; urine inulin concentration = 60 mg/ml; plasma inulin concentration = 2 mg/ml; urine potassium concentration = 20 μmol/ml; plasma potassium concentration = 4.0 μmol/ml; urine osmolarity = 150 mOsm/L; and plasma osmolarity = 300 mOsm/L. What is the net potassium reabsorption rate?

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#Question id: 12697

#Unit 7. System Physiology – Animal

The following test results were obtained: urine flow rate = 2.0 ml/min; urine inulin concentration = 60 mg/ml; plasma inulin concentration = 2 mg/ml; urine potassium concentration = 20 μmol/ml; plasma potassium concentration = 4.0 μmol/ml; urine osmolarity = 150 mOsm/L; and plasma osmolarity = 300 mOsm/L. What is the approximate GFR?

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#Question id: 12659

#Unit 7. System Physiology – Animal

 Which of the following would tend to decrease plasma potassium concentration by causing a shift of potassium from the extracellular fluid into the cells?

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#Question id: 12658

#Unit 7. System Physiology – Animal

In a person on a high (200 mmol/day) potassium diet, which part of the nephron would be expected to secrete the most potassium?