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: 12271

#Unit 7. System Physiology – Animal

A young woman comes to the emergency room with a vertebral compression fracture. Radiographs of the spine indicate generalized demineralization. She is vegetarian, does not smoke or drink alcohol, has normal plasma potassium concentration of 5.4 mEq/L, sodium concentration of 136 mEq/L, plasma calcium concentration is 7.0 mg/dL. Her vitamin D3 value is several times greater than normal, although her 1,25-dihydroxycholecalciferol concentration is at the lower limit of detectability. She has been in renal failure for the last 5 years and undergoes hemodialysis three times each week. What is the cause of her low 1,25-dihydroxycholecalciferol level?

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#Question id: 12272

#Unit 7. System Physiology – Animal

A neonate develops a jaundice condition with a bilirubin concentration of 10 mg/dL on day 2 (normal is 3 mg/dL at 2 days old). The neonatologist can be confident that the condition is not erythroblastosis fetalis if which of the following is true?

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#Question id: 12273

#Unit 7. System Physiology – Animal

Which of the following findings would likely be reported in a patient with a deficiency in iodine intake?

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#Question id: 12274

#Unit 7. System Physiology – Animal

Before intercourse, a woman irrigates her vagina with a solution that lowers the pH of the vaginal fluid to 4.5. What will be the effect on sperm cells in the vagina?

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#Question id: 12275

#Unit 7. System Physiology – Animal

Two weeks after constricting the renal artery of a sole remaining kidney to initially reduce renal artery pressure by 20 mm Hg (from 100 to 80 mm Hg), which of the following changes would you expect, compared with before constriction of the artery?

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#Question id: 12276

#Unit 7. System Physiology – Animal

Because the usual rate of phosphate filtration exceeds the transport maximum for phosphate reabsorption, which of the following is true?