Hematocrit increases in venous blood due to

CHLORIDE SHFTFor each CO2 molecule added to a red cell, there is an increase of one osmotically active paicle in the cell-- either an HCO3- or a Cl- in the red cell (Figure 36-6). Consequently, the red cells take up water and increase in size. For this reason, plus the fact that a small amount of fluid in the aerial blood returns the lymphatics rather than the veinsThe hematocrit of venous blood is normally 3% greater than that of the aerial blood. In the lungs, the Cl- moves out of the cells and they shrink.Thus increased Cl- in venous blood cause increased hematocrit