Osmolarity and tonicity Flashcards
(14 cards)
What is diffusion ?
Particles move from an area of high concentration to an area of low concentration down a concentration gradient
What is osmosis ?
Movement of water molecules from an area of high water concentration to an area of low water concentration across a semi-permeable membrane
What is hydrostatic pressure ?
The pressure exerted by a stationary fluid on an object
A “pushing force”
What is osmotic pressure ?
A measure of the tendency for water to move into a solution because of its relative concentration of non-penetrating solutes and water
A “pulling force”
What is the interstitial fluid ?
The fluid found in the spaces around cells
What is molarity ?
The number of molecules in a solution (Mol/L)
What is osmolarity ?
The number of particles in a solution (Osm/L)
The difference between molarity and osmolarity depends on the substance. Describe 2 examples.
- Glucose- molecules do not separate out in solution, therefore molarity and osmolarity are the same.
- NaCl- separates out into two different ions, therefore the osmolarity is double the molarity
What is tonicity ?
The effect the osmotic pressure gradient has on cell volume
What is a hypotonic cell ?
Water moves into the cell by osmosis, causing it to swell
There is a lower solute concentration outside compared to inside of the cell
What is a hypertonic solution?
Water moves out of the cell by osmosis, causing it to shrink
There is a higher solute concentration outside the cell compared to the inside of the cell
What is an isotonic solution ?
When the two solutions have the same solute concentration, so there will be no net movement of water into the cell
What is the difference between osmolarity and osmolality ?
Osmolarity- osomoles per volume
Osmolality- osmoles per weight (normally kg)
What occurs when cells swell due to too much water coming in ?
Regulatory volume decrease (RVD)
