+ H 2 CO 3 ATP Lumen H + 3Na + Carbonic anhydrase Early Proximal tubule H 2 O + HCO 3 - H 2 CO 3 Carbonic anhydrase CO 2 H 2 O HCO Na + Glucose 2K + Na + H+H+ Base - Cl - (65 -80) K + H 2 O Cl - Blood vessel Na + CO 2 HCO 3 - H +

+ H 2 CO 3 ATP Lumen H + Na + Carbonic anhydrase Early Proximal tubule H 2 O + HCO 3 - H 2 CO 3 Carbonic anhydrase CO 2 H 2 O HCO Na + Glucose K + Na + H+H+ Base - Cl - (65 -80) K + H 2 O Cl - Blood vessel Na + CO 2 HCO 3 - H +

Glucose titration curve Glucose Glucose Excreted Glucose Reabsorbed GFR = 125mL/min Glucose Filtered [Glucose] plasma (mg/dL K = RPT Tm G = 375mg/min Glucose flux (mg/min) Splay

Changes in % of renal filtrate Proximal tubuleLoop of HenleDistal tubuleCollecting tubule Fraction remaining in tubular fluid Na + Water Urea D A C B

Changes in % of renal filtrate Proximal tubuleLoop of HenleDistal tubuleCollecting tubule Fraction remaining in tubular fluid Na + Glucose Water Urea Inulin Creatinine F D A C B E

Case 1 A 75-year-old man is brought to the emergency department because of diarrhea and vomiting for the last 24 hours. The patient lives at home with his son, and his son states that his father has been unable to take in much fluid since his symptoms began. On examination, his mucous membranes are dry and his blood pressure is 90/60 mm Hg. What changes do you expect in the renal plasma flow (RPF) of this patient? Would there be any change in his glomerular filtration rate (GFR)? What impact would this patient physiological state have on his filtration fraction?

RPFGFRFF

A 27-year-old woman is being monitored in the intensive care unit after she sustained head trauma in a motor vehicle accident 3 days ago. She has undergone computed tomographic imaging of her head, which revealed cerebral swelling but no evidence of hemorrhage or brain herniation. The patient has been in critical but stable condition. The nurse calls the physician because the patient has developed hypernatremia and has had a significant increase in dilute urine output. The findings are confirmed, and it is determined that the patient has central diabetes insipidus as a result of the head trauma. How are antidiuretic hormone (ADH) levels affected in patients with this condition? What is the effect of high ADH on the late distal tubule and collecting ducts? How does free-water clearance change in the presence of ADH?

Solute reabsorption at PCT Cl-

+ H 2 CO 3 ATP Lumen H + Na + Carbonic anhydrase Early Proximal tubule H 2 O + HCO 3 - H 2 CO 3 Carbonic anhydrase CO 2 H 2 O HCO Na + Glucose K + Na + H+H+ Base - Cl - (65 -80) K + H 2 O Cl - Blood vessel Na + CO 2 HCO 3 - H +

ATP Lumen Na + Thick ascending loop of Henle Na + K + Ca 2+ ( ) CA 2+ Na + Cl - Blood vessel Na + 2Cl - Na + K + Na + K + Cl - Ca2 + Na +

ATP Lumen Na + Early distal convoluted tubule K + Ca 2+ K+K+ Cl - 2Cl - Na + K + K+K+ Mg 2+, Cl - Diffusion down the electrochemical gradient Loop diuretics 5% Blood vessel

ATP Lumen Na + Collecting Duct K + Cl - Na + K + H20H20 K + sparing diuretics 5 - 7% V2V2 ADH Principal Cell Intercalated cell R Water channel molecules Blood vessel Aldosterone H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H 2 OH2OH2O H2OH2O H2OH2O H2OH2O Na + K +

ATP Lumen Na + Collecting Duct K + Ca 2+ Cl - Na + K + H20H20 Mg 2+, K + sparing diuretics 5 - 7% V2V2 ADH Principal Cell Intercalated cell ATP H + HCO 3 - Cl - R Water channel molecules Blood vessel K + Aldosterone H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H 2 OH2OH2O H2OH2O H2OH2O H2OH2O Na + K +

Glucose titration curve Glucose Glucose Excreted Glucose Reabsorbed GFR = 125mL/min Glucose Filtered [Glucose] plasma (mg/dL K = RPT Tm G = 375 mg/min Glucose flux (mg/min) C A K I H F