BIOL 1840U Lecture Notes - Aldosterone, Glutamine, Carbonic Anhydrase
Document Summary
2. large drop in luminal ph: 6. 8 4. 5: co2 from blood continues to move into cells, where carbonic anhydrase breaks it down => new hco3!! to blood stream, ammonia (nh4+) 1: strong acids are broken down and excreted as ammonia (nh4+) and a- Nh3 + h+ nh4: nh3 readily diffuses thru cell membranes, nh4+ is less permeable, ammonia generated from glutamine breakdown in mitochondria; also generates a-ketogluterate => new hco3 production! Base producing diet: urine is alkaline b/c excess base is secreted, differences from acid-producing diet, reduced reabsorption of hco3 by pct, no titration of weak acids, decreased production of nh4, secretion of hco3 by collecting ducts. Control of net acid/base excretion: plasma ph, renal cells can detect changes in ph and pco2, na/h exchangers & h+ pumps both have h+ sensors => ph causes. Metabolic acidosis excess production of keto-acids => ic, ec, & urine ph => compensation for acid by lungs & kidneys.
