Clinical VignetteQuestion 1 of 24
Loop's Target
A 68-year-old woman is brought to the emergency department because of a 3-day history of progressive dyspnea and bilateral lower extremity swelling. She has a history of coronary artery disease and heart failure with reduced ejection fraction. Her medications include lisinopril, metoprolol, and aspirin. Her pulse is 92/min, respirations are 22/min, and blood pressure is 148/88 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 92%. Physical examination shows jugular venous distension to 10 cm, bibasilar pulmonary crackles, and 3+ bilateral pitting edema to the mid-shins. She is given intravenous furosemide 40 mg. Within 2 hours, she produces 800 mL of urine and her respiratory distress improves. Furosemide inhibits the Na⁺/K⁺/2Cl⁻ cotransporter in the renal tubule.
This medication exerts its primary diuretic effect by acting on which of the following nephron segments?