Nutrition Science and Everyday Application - beta v 0.1

VITAMINS AND MINERALS INVOLVED IN FLUID AND ELECTROLYTE BALANCE 465
Figure 8.8. Effect of fluid imbalance on cells. With dehydration, the concentration of electrolytes
becomes greater outside of cells, leading to water leaving cells and making them shrink. In fluid
balance, electrolyte concentrations are in balance inside and outside of cells, so water is in
balance too. During overhydration, electrolyte concentrations are low outside the cell relative to
inside the cell (like in the situation of hyponatremia), so water moves into the cells, making them
swell.
The cell is able to control the movement of the two major cations, sodium and potassium,
with a sodium-potassium pump (Na + /K + pump). This pump transports sodium out of cells
while moving potassium into cells.
Figure 8.9. The sodium-potassium pump is found in many cell (plasma) membranes. Powered