BIOL 031 Lecture Notes - Lecture 13: Ammonia, Extracellular Fluid, Kidney Stone Disease

• School: College of The Sequoias
• Department: Biology (BIOL)
• Course: BIOL 031
• Professor: carey

Document Summary

Describe how the various segments of the nephron contribute to the process of reabsorbing the filtered hco3- (mks 1a) Apical side aka tubular fluid aka lumen. + h+ h2co3 (tubular carbonic anhydrase, located on the microvilli/brush border) h2o + co2. H2o + co2 cross the apical membrane into the proximal tubular cell. H2o + co2 + (cytosolic carbonic anhydrase) hco3 intracellular + h+ H+/na+ antiporter or proton pump can get h+ out of the cell. Intracellular can travel out of the cell into the interstitium. Cotransporter (more common) and a hco3 via a na+/3hco3. Net: each bicarb removed by lumen is 1 bicarb gained by blood. Proximal tubule interference causes bicarbonate wastage, not really the other ones. Hco3-/cl- exchangers in the basolateral membrane, hco3 exits the cell into interstitial space. H+ and hco3 are produced within the cell (using carbonic anhydrase, smaller amounts than in pct) H+ is secreted by h+ atpase and h+-k+ atpase.