What is the Cl- shift in the RBC for systemic gas exchange?

The Cl- shift, also known as the Hamburger phenomenon, occurs in red blood cells (RBCs) during systemic gas exchange. As carbon dioxide (CO2) enters the RBCs from the tissues, it combines with water to form carbonic acid, which dissociates into bicarbonate (HCO3-) and hydrogen ions (H+). To maintain electrical neutrality, bicarbonate is transported out of the RBCs into the plasma while chloride ions (Cl-) move into the cells, thus the “shift” of Cl- into the RBCs. This process helps facilitate the transport of CO2 from tissues to the lungs for exhalation.