Page 34 - Color_Atlas_of_Physiology_5th_Ed._-_A._Despopoulos_2003

A. Diffusion in homogeneous media
1 Brownian particle
movement ( T)
~
2 Passive transport
3 PO 2 profile
Gas O 2
PO 2
O 2 O 2 O 2
PO 2
0
Slope=gradient Passive Transport by Means of Diffusion I
X P =dP/dx
PO 2 x
Water
P
x
0
Distance from O 2 source (x)
B. Diffusion through porous membranes
1 Porous membrane 2
Space a Space b Plate 1.10
C a

C b Gradient b
Pore C
C a

Space a Membrane Space b
∆x a b
C –C =∆C
C. Diffusion through lipid membranes
1 2
5nm Hydrophilic Hydrophobic
substance X substance Y
a (k<1) (k>1)
CX
a Gradient
CY
Gradient b
CX
b
CY
Lipid Lipid
Water membrane Water Water membrane Water
Equilibrium concentration in olive oil
k =
Equilibrium concentration in water 21
21
(Partly after S.G.Schultz)
Despopoulos, Color Atlas of Physiology © 2003 Thieme
All rights reserved. Usage subject to terms and conditions of license.