Transport of Solutes/Water

Transport

Movements of SOLUTES (dissolved material) and or or WATER across CELL MEMBRANES or EPITHELIA in order to:
■ resupply cells/tissues with needed raw materials
■ Concentrate materials when/where needed
■ Void wastes
■ Maintain proper composition of body fluids

Cell Membrane Permeability

Some solutes dissolve in the membrane to pass through
● permeability depends on diffusion through lipid molecular size etc.
Some solutes require channels:
● Permeability depends on number of channels per unit of membrane area & channels open = selectively permeable.

Electrochemical Equilibrium

Chemical and electrical gradients are equal in magnitude.

Membrane Potential

Difference in the electric potential between the interior and exterior of a cell.

Electrogenic

Creates a charge imbalance across the membrane.

Colligative Properties

Properties of a solution that depend simply on the number of dissolved entities per unit volume.
osmotic pressure
freezing point
vapor pressure

Osmotic Pressure

Property of a solution that allows one to estimate if it will gain or lose water by osmosis.

Higher solute (lower solvent) concentration, higher
osmotic pressure.

Isosmotic

Equal osmotic pressure

Hyposmotic

Having a lower osmotic pressure in comparison to
another solution.

Hyperosmotic

Having higher osmotic pressure in comparison to
another solution.