Question

As the blood & other extracellular fluids (ECF) become hypotonic, the tissue cells undergo:

crenation

no change

swelling

atrophy

stasis

Answer 1

As the blood and other extracellular fluids (ECF) becomes hypotonic, the tissue cells undergo?

Answer: swelling.

Explanation: If the tissue cells are surrounded by blood or extracellular fluids(ECF) which is hypotonic, there is movement of water from the the surrounding blood or ECF into the tissue cells due to osmosis resulting in swelling of the cells. If the movement of water and consequent swelling of the cells continue, it results in breakdown of the cells called hemolysis.

Osmosis is the movement of solvent (mainly the water) from a solution of low solute concentration (hypotonic solution) to a solution of high solute concentration (hypertonic solution). For osmosis to occur, the two solutions should be seperated by a semipermeable membrane.

Thus, when the cells are placed in a hypotonic environment, water from outside enters the cells resulting in swelling of the cells as the cells have more solutes (hypertonic) as compared to the outside environment (hypotonic) and cell membrane acts as the semipermeable membrane.

If the tissue cells are placed in an hypertonic environment, water from inside the cells (hypotonic) move out into the outside environment (hypertonic) causing cremation of the cells.

If the cells are placed in an isotonic environment, there is no not gain or loss of water as both the cells and external environment have the same tonicity. Hence, the cells remain unaffected.