Question

If the ECF is hypertonic with respect to the ICF, water will move

options:

in response to the sodium-potassium exchange pump

. in both directions until osmotic equilibrium is restored.

from the ECF into the cells until osmotic equilibrium is restored

. from the cells into the ECF until osmotic equilibrium is restored.

Answer 1

Answer:

Option D (from the cells into the ECF until osmotic equilibrium is restored)

Explanation: Every cell; predominantly the nerve cell has an extra cellular fluid composition (ECF) as well as an ICF (intracellular fluid) composition.

Their composition is as follows:

ICF: High amount of potassium ions, negatively charged proteins, magnesium and phosphate

ECF: High amount of sodium ions

Thus, because of their compositions the inside of the cell is negative (majorly attributed due to the presence of negatively charged proteins and difference in the concentrations of the sodium and potassium ions) whereas the outside of the cell is positive.

However, apart from the composition listed above, the water concentration has to be maintained at both the sides of the cell; that is equal amount of water has to be present intracellularly and extracellularly such that there is only the mediation and movement of the ions.

Since, in the given question the extracellular fluid matrix is hypertonic with respect to the intracellular fluid composition; that is the ECF contains more amount of as compared to that of the ICF. Henceforth, in order to maintain the ionic equilibrium, the water molecules will move from the ICF cells into the ECF until the osmotic equilibrium is restored.