What happens if the salt concentration in the internal environment is higher than normal?

A solution with a high concentration of salts (relative to the norm or another solution) is called hypertonic.

In the internal environment, it is very important to maintain a constant concentration of salts, otherwise its changes can lead to irreversible consequences (nerve conduction will be disturbed, etc.). If the concentration inside the cell is higher than outside, then due to osmosis, fluid from the surrounding space will rush into the cell, trying to equalize the concentration. The cell will swell and may burst. Therefore, it is important to maintain a constancy of the internal environment.