Table 1.

Dimensions of jejunal enterocytes of hamster, rat and human used to calculate the cross-sectional area and length of the paracellular pathway

	Non-absorbing				Absorbing
	rs	rb	xb	Vcell	rs	h	Vcell	rb
Hamster	4.75	4.00	21	1503*	4.75	4	1040*	2.4
Rat	3.65	3.1	28	1181*	3.65	5*	825*	1.9*
Human	5.5	4.80	36	3500*	5.50	6*	2452*	3.0*

Measured values are shown in plain type

^*indicates calculated values. All values are given in μm or μm³, as appropriate. On the basal side of the tight junction, the cells are treated as truncated cones with radii of r_s at the level of the tight junction and r_b at the level of the basement membrane. The height of the cone is x_b and the distance from the brush border to the basal side of the tight junction is h (see Fig. 2A). V_cell, volume of cell.