Osmosis and Tonicity

What is Osmosis?

Movement of water across membrane Diffusion of water through a membrane Unaffected by membrane potential Goes to a higher concentration

What is the number for intracelluar and extracelluar fluid?

300 mOsm.

What is Osmosis driven by?

Driven by water gradient: Goes from high concentration to low concentration in terms of concentration of water Water is going to move down its concentration gradient

What is Iso-Osmotic?

In osmolarity DEF: No net movement of water 1. As much water moves out, that much water moves in 2. Same osmolarity as fluid of water Not isotonic; could still cause cell to swell depending on solution Filled with impermeable solutes, will not swell If want to change solution to isotonic, you would put another impermeable solute to make it 300 mOsm

What is Osmolarity

Movement of water across membrane Has Iso-Osmotic, Hyperosmoticm Hyo-Osmotic, and impermeable solutes Affected by concentration gradient Less solute= more water More water= less solute

What is Osmotic pressure?

Pressure of movement water is going to exert Smaller concentration gradient= small osm. Pressure Osm pressure would take it to stop water of movement Reflects total solute concentration Ability to pull water is the pressure that would be applied to stop any water movement

What happens when the membrane is permeable to water?

Solutes will move out of the membrane

What is Hyo-Osmotic? (Hypotension)

Water goes down CG, cells are going to lice or blow up

What is Tonicity?

Water gradient across a membrane caused by impermeant solute

What is Hyper-Osmotic? (Hypertension)

Water move down its concentration gradient and cells shrivel

What happens when the membrane is impermeable to water and not to solute?

We will have a diffusion