Changes

* The secretion of H⁺ in this section of the nephron is mainly a result of the Na⁺/H⁺ antiporter in the apical membrane using secondary active transport.

* The secretion of H⁺ in this section of the nephron is mainly a result of the Na⁺/H⁺ antiporter in the apical membrane using secondary active transport.

*HCO₃^- is reabsorbed here in a different way to other substances.  The presence of hydrogen in the lumen causes some amount of it to dissociate to carbon dioxide and water via the enzyme carbonic anhydrase.  These enter the epitehlial cells where they are reformed using the same enzyme.  The HCO₃^- then leaves the cell using the basolateral 3HCO₃^-/Na⁺ symporter.

*HCO₃^- is reabsorbed here in a different way to other substances.  The presence of hydrogen in the lumen causes some amount of it to dissociate to carbon dioxide and water via the enzyme carbonic anhydrase.  These enter the epitehlial cells where they are reformed using the same enzyme.  The HCO₃^- then leaves the cell using the basolateral 3HCO₃^-/Na⁺ symporter.

*[[Acid Base Balance By The Kidney - Anatomy & Physiology#Secretion of H+ and the Reabsorption of HCO3- in the Proximal Tubule|Link to Article]]</TD>

*[[Reabsorption and Secretion Along the Proximal Tubule - Anatomy & Physiology|Link to Article]]</TD>

<TD BGCOLOR="#C1f0f6"><center>N/A</center></TD>

<TD BGCOLOR="#C1f0f6"><center>N/A</center></TD>

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*Hydrogen is excreted in the collecting ducts both in exchange for potassium and on its own using an ATPase.   

*Hydrogen is excreted in the collecting ducts both in exchange for potassium and on its own using an ATPase.   

*Bicarbonate is reabsorbed.</TD>

*Bicarbonate is reabsorbed.

*[[Reabsorption and Secretion Along the Distal Tubule and Collecting Duct - Anatomy & Physiology#H+ and HCO3-|Link to Article]]</TD>

<TD BGCOLOR="#C1f0f6"><center>N/A</center></TD>

<TD BGCOLOR="#C1f0f6"><center>N/A</center></TD>

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