Fluid compartments and osmosis Flashcards
Why is osmosis important?
Osmotic stability
Appropriate cell volume
Ionic gradients
What is intracellular fluid?
Fluid within a cell
What is interstitial fluid?
Fluid that surrounds all cells
What is extracellular fluid?
All bodily fluid outside the cell
Name the 5 fluid categories
Extracellular Intracellular Interstitial Transcellular Plasma
What two things make up extracellular fluid/
Interstitial fluid
Plasma
What is osmosis?
Passive diffusion of water through semi-permeable membrane
Driven by concentration gradient
What is osmotic pressure?
The amount of pressure that will prevent net flow of water
What is osmolarity?
Osmoles per litre
Total solute concentration/ litre of solution
What is the osmolarity of a 1M solution
1 Osmol/L
How do you calculate osmoles in a substance that dissociates?
100mM solution of NaCl has an osmolarity of 200 mOsmol/L because it dissociates to Na+ and Cl-
What is osmolality?
Osmoles per kg
What is body fluid osmolality?
280-296 mOsmol/Kg H2O
What does osmolarity not tell us?
What will happen when a cell is placed in that solution
What does isosmotic mean?
Solutions contain equal solutes. Have equal osmolarity
What does hyperosmotic mean?
The solution has greater osmolarity than the other
What does hyposmotic mean?
The solution has a low osmolarity than the other
What is tonicity?
Tonicity describes the volume change of a cell
It has no units
It is always relative to the cell
What happens when a cell is in an isotonic solution?
Its volume remains the same
What happens to a cell in a hypertonic solution?
The cell shrinks
What happens to a cell in a hypotonic solution?
The cell swells
What might retention of organic anions lead to?
Creates an osmotic gradient
Creates an electrical gradient
Cell swells
How is osmotic balance achieved?
Extrusion of Na+
