3: Secondary Active Transport, Diffusion Potential and Osmosis Flashcards
Symport or co-transport
second solute moves in same direction as Na+
Antiport or counter-transport
second solute moves in opposite direction as Na+
What is the effect of digitalis on transmembrane ion concentrations?
inhibits ATPase and intracellular Na+ increases, extracellular K+ increases, therefore increasing the concentration of other ions that depend on secondary active transport, such as Ca+2
equilibrium potential
the diffusion potential that would have to exist across the membrane to prevent the movement of an ion down its concentration gradient
Nernst equation
describes the balance of electrochemical forces; the electric potential difference across the membrane opposes the diffusion of solute down its concentration gradient
Osmosis
the flow of H2O through aquaporins in a semi-permeable membrane due to differences of impermeant solute concentrations
hypotonic
low osmotic pressure
hypertonic
hight osmotic pressure
Water flows from ___ to ___ osmotic pressure
low to high
osmole
unit describing number of moles of a solute that contribute to the osmotic pressure of a solution
osmolality
number of osmoles of solute/l of solvent
Albumin
contributes a lot of colloid osmotic pressure and protein in plasma
Where is albumin produced?
liver
What prevents the loss of fluid in the interstitial tissue?
albumin
osmotic pressure in arteries
high
