Final answer:
An increase in sodium in the extracellular fluid causes a hypertonic environment leading to water leaving the cells, resulting in cell dehydration and potentially increased blood pressure.
Step-by-step explanation:
An increased amount of sodium in the extracellular fluid leads to a hypertonic environment around the cells. According to the principles of osmosis, water flows from a region of lower solute concentration to a region of higher solute concentration. Hence, if the extracellular fluid has increased Na+ levels, water will move out of the cells into the extracellular space to balance the concentration gradient. This will lead to cell dehydration.
Over time, this imbalance can lead to various health issues, including increased blood pressure due to the excess volume of water in the body. Cell dehydration may also result in slowed circulation and impaired cellular functions.