Urine and Acid-Base Balance

• which of the ingested liquid groups will have the lowest urine osmolarity?

  tap water
• which of the ingested liquid groups will have the highest urine osmolarity?

  vasopressin
• - decreased ECF osmolarity

  - decreased ADH

  - decreased urine osmolarity

  - increased urine volume

  - increased urine flow


  tap water ingestion
• - decreased ECF osmolarity

  - increased ADH

  - increased GFR

  - decreased urine volume

  - decreased urine flow

  - increased EFC volume and BP

  - decreased aldosterone

  - increased urine osmolarity

  - increased urine Na+ quantity


  vasopressin ingestion
• - decreased ECF osmolarity

  - decreased ADH

  - increased GFR

  - increased urine volume

  - increased urine flow


  caffeine ingestion
• - increased ECF osmolarity

  - increased ADH

  - increased ECF volume and BP

  - decreased aldosterone

  - increased GFR

  - increased urine Na+ quantity

  - increased urine osmolarity


  sodium chloride ingestion
• - increased urine pH

  - everything else unchanged or hard to tell

  0.5% sodium bicarbonate ingestion
• - no ADH

  - increased urine volume

  - increased urine flow

  - decreased urine osmolarity

  - decreased ECF osmolarity


  beer ingestion
• will increasing arterial blood PCO2 have any effect on plasma pH?

  decrease pH in plasma
• in response to a decrease in plasma pH, what do you expect the urinary H+ concentration and HCO3- concentration to be compared to a healthy, typical subject?

  the H+ concentration will increase and the HCO3- will decrease
• PCO2 = 20 mmHg

  plasma pH = 7.68

  [H+] in urine decreases

  [HCO3-] in urine increases
• PCO2 = 40 mmHg

  plasma pH = 7.38

  [H+] in urine is normal

  [HCO3-] in urine is normal
• PCO2 = 90 mmHg

  plasma pH = 7.08

  [H+] in urine increases

  [HCO3-] in urine decreases
• the relationship between PCO2 and plasma pH

  they're inversely proportional