BIOL373 Lecture Notes - Lecture 18: Respiratory Alkalosis, Respiratory Acidosis, Metabolic Alkalosis
2 Sep 2019
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Indirectly by changing in the reate at which hco3. Is reabsorbed or excreted: usually three mechanisms (buffers, resp, renal) are able to prevent major changes in plasma ph. If plasma ph moves out of normal range, buffering has been overwhelmed, it is up to respiratory and renal mechanisms. If primary cause respiratory, only renal mechanisms remain. If primary cause metabolic, both resp and renal mechanisms can be used. Ventilation and ph homeostasis: hypoventilate: reaction shifts right, higher [h+] acidosis, hyperventilate: reaction shifts left, lower [h+] alkalosis. Overview of renal compensation for acidosis: two general mechanisms, excreting (vs reabsorbing) h, reabsorbing (vs excreting) hco3, excreted h+ is buffered by nh3 and hpo42. Where in the nephron is this happening: huge amounts of bicarbonate are filtered at the glomerulus, that must be reabsorbed to maintain buffering capacity, occurs in proximal tubule, no transporters for hco3. On apical membrane, so indirect method used: fine tuning of acid-base balance carried out in distal nephron.
