The net direction of bicarbonate-chloride exchange (bicarbonate out of RBCs in the systemic capillaries, bicarbonate into RBCs at pulmonary capillaries) proceeds in the direction that decreases the sum of the electrochemical potentials for the chloride and bicarbonate ions being transported. Inflow of chloride ions maintains electrical neutrality of a cell. Continuous process of carbonic acid dissociation and outflow of bicarbonate ions would eventually lead to a change of intracellular electric potential because of lasting H+ ions. The underlying properties creating the chloride shift are the presence of carbonic anhydrase within the RBCs but not the plasma, and the permeability of the RBC membrane to carbon dioxide and bicarbonate ion but not to hydrogen ion. Reaction (as it occurs in the pulmonary capillaries)īicarbonate in the red blood cell (RBC) exchanging with chloride from plasma in the lungs. The chloride shift may also regulate the affinity of hemoglobin for oxygen through the chloride ion acting as an allosteric effector. Inward movement of bicarbonate via the Band 3 exchanger allows carbonic anhydrase to convert it to CO 2 for expiration. The subsequent decrease in intracellular bicarbonate concentration reverses chloride-bicarbonate exchange: bicarbonate moves into the cell in exchange for chloride moving out.
#SHIFT EXCHANGE FREE#
This releases hydrogen ions from hemoglobin, increases free H + concentration within RBCs, and shifts the equilibrium towards CO 2 and water formation from bicarbonate. The opposite process occurs in the pulmonary capillaries of the lungs when the PO 2 rises and PCO 2 falls, and the Haldane effect occurs (release of CO 2 from hemoglobin during oxygenation). With these files, a row can be moved to the left or right.
For a VECTOR, it may be necessary to shift the elements across, up or down the line. Sometimes it is required to SHIFT a row or column RELATIVE to the other elements in a MATRIX. Consequently, chloride concentration is lower in systemic venous blood than in systemic arterial blood: high venous pCO 2 leads to bicarbonate production in RBCs, which then leaves the RBC in exchange for chloride coming in. This set of files was developed using MATLAB Version 5. The term "chloride shift" refers to this exchange. Thus, the rise in intracellular bicarbonate leads to bicarbonate export and chloride intake. H +, HCO 3 − ) but RBCs are able to exchange bicarbonate for chloride using the anion exchanger protein Band 3. In response to the decrease in intracellular pCO 2, more CO 2 passively diffuses into the cell.Ĭell membranes are generally impermeable to charged ions (i.e.
Carbonic acid then spontaneously dissociates to form bicarbonate Ions (HCO 3 −) and a hydrogen ion (H +). It dissolves in the solution of blood plasma and into red blood cells (RBC), where carbonic anhydrase catalyzes its hydration to carbonic acid (H 2CO 3). Mechanism Ĭarbon dioxide (CO 2) is produced in tissues as a byproduct of normal metabolism. Chloride shift (also known as the Hamburger phenomenon or lineas phenomenon, named after Hartog Jakob Hamburger) is a process which occurs in a cardiovascular system and refers to the exchange of bicarbonate (HCO 3 −) and chloride (Cl −) across the membrane of red blood cells (RBCs).
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