Osmosis and Tonicity

Flashcards covering key vocabulary related to osmosis and tonicity, including definitions of diffusion, osmosis, selectively permeable membrane, and different types of tonicity (isotonic, hypotonic, hypertonic).

Diffusion

Refers to the movement of solute.

Osmosis

The passive process of solvent movement from a solution with a lower solute concentration to a solution with a higher solute concentration, occurring only through a selectively permeable membrane. In biological systems, the solvent is generally water.

Selectively permeable membrane

A membrane that allows the solvent to cross but not the solute particles, crucial for osmosis.

Tonicity

Describes one solution's ability to cause osmosis relative to another, used to compare solute concentration of two solutions (e.g., cytosol and ECF).

Isotonic ECF

An extracellular fluid that has the same solute concentration as the cytosol, resulting in no net movement of water into or out of a cell.

Hypotonic ECF

An extracellular fluid that has a lower solute concentration than the cytosol, causing water to move into the cell by osmosis, which may lead to the cell swelling and bursting.

Hypertonic ECF

An extracellular fluid that has a higher solute concentration than the cytosol, causing the ECF to pull water molecules out of the cytosol by osmosis, which may cause the cell to shrivel or crenate.

Crenate

To shrivel or shrink, typically referring to a cell losing water to a hypertonic extracellular fluid by osmosis.