Term
| Reabsorption of bicarbonate here is linked to reabsorption of Na+, and secretion of H+ and K+ |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| Bicarbonate reabsorption is catalysed by the Na+/K+ATPase pump in the basolateral cell membrane here |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| Peritubular K+ is exchanged for intracellular Na+ to keep intracellular Na+ low here |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| Na+ enters the cell by moving down its concentration gradient here |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| H+ ions move out of the cell and into the tubular lumen via the H+/Na+ antiport here |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| HCO3- is transported down its concentration gradient into peritubular fluid here |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| CO2 diffuses down its concentration gradient into these cells and reacts with H2O to form HCO3- and H+ again |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| All H+ secreted here is regenerated into HCO3- and reabsorbed |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| Na+/K+ATPase pumps exchange Na+ for K+ to keep intracellular Na+ levels low here |
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Definition
| Principal cells of the collecting duct |
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Term
| Na+ is cycled into these cells in exchange for K+ via antiport here |
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Definition
| Principal cells of the collecting duct |
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Term
| Despite the exchange of Na+ for K+, a negative charge is created in the tubule lumen here |
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Definition
| Principal cells of the collecting duct |
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Term
| H+ is pumped out of these cells by the H+ proton pump in exchange for K+ to maintain neutrality here |
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Definition
| Intercalated cells of the collecting duct |
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Term
| H+ pumped out into the lumen via the proton pump is buffered by HPO4 and excreted as phosphate (a titratable acid) here |
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Definition
| Alpha intercalated cells of the collecting duct |
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Term
| Excess H+ in the capillary blood is buffered by HCO3-, lowering blood pH here |
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Definition
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Term
| CO2 from the buffering reaction in the blood moved into these cells and is dissociated to HCO3- and H+ here |
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Definition
| Intercalated cells of the collecting duct |
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Term
| HCO3- diffuses down its gradient back into peritubular capillaries to raise blood pH again here |
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Definition
| Intercalated cells of the collecting duct |
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Term
| The ammonium buffer system is at work in this area |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| Glutamine diffuses into these cells to generate ammonia |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| NH3 diffuses into the tubule lumen and becomes acidified to ammonium in this area |
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Definition
| Proximal convoluted tubule (PCT) |
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Term
| NH4+ combined with Cl- to form NH4Cl (a form able to be excreted) here |
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Definition
| Proximal convoluted tubule (PCT) |
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