Module 3.1 - Biomass Transport I (Fundamentals) Flashcards
Androgenesis
Growth of blood vessels off other blood vessels
What happens when cells have low O2?
cells starving of O2 and other nutrients secrete signal molecules, which activate vessel movement/growth towards the area to feed low O2-tissue
Why does our skin lose more moisture in the winter?
Amount of water in air is lower, so driving force is low. Barrier properties of skin change with moisture
Mass transfer
Movement of one or more molecular species relative to others in a mixture (moving randomly)
T/F: Diff speeds of molecules depend on their size and internal energy
T
Flux of species A is given by…
mass: j_A = rho_A(v_A - v) = n_A - rho_A*v
mole: J_A = c_A(v_A - v) = N_A - c_A*v
T/F: Diffusion always occurs in steady state conditions
F: occurs in non-ss conditions
Diffusivity constant
Representation of resistance to diffusion/movement (the amount of a particular substance that diffuses across a unit area in 1 s under the influence of a gradient of one unit)
Estimate radius of solute by assuming ________
Perfect sphere
Stokes-Einstein equation assumes…
Solute molecules are much bigger than solvent
Equilibrium
System is in equilibrium with surroundings if there is equal transfer across the boundaries (no net exchange)
Partition coefficient
Describes how a solute is distributed between two immiscible solvents. Shows solubility preference/which phase is more favourable
T/F: In liquid-gas equilibrium, air and water is extremely ideal
F: not ideal. Cannot use Raoult’s Law, but can use Henry’s
Function of heart-lung machines
Blood is oxygenated via a polycarbonate membrane that separates blood from supply of sterile air. Used when heart stops beating and surgery must be done
Flux across membrane driving force
Conc gradient
T/F: There may be partitioning of drug into membrane, THEN movement through membrane
T
Cause of stagnant boundary layers on each side of the membrane
Force of heat pushing molecules on either side of membrane (now technically 3 memb for solute to move through)
T/F: If we assume infinite vol for concentration to dissolve, we’re adjusting C_A,1 and C_A,2 outside BL
F: If we have infinite volume for concentration to dissolve, we have constant concentrations of C_A,1 and C_A,2 outside BL
Once inside the system, we assume everything is ______
Well-mixed
Why do we assume infinite time frame of A diffusing through a membrane wall?
Steady state
Microscopic species balance
Assumes the concentration of the species is the same everywhere in the control volume (can’t make this assumption for many physiological transport problems)
How many boundary conditions do we need to solve Fick’s 2nd Law?
3: 1 IC for initial time frame or infinite cond’t, and 2 ICs for boundaries (due to double differential)
T/F: We’re more interested in concentration profile rather than flux
F: opposite, flux > profile
