Page 13, Turbulence & Rheology, Dr. D. Penney
Flow through capillaries is quite different from that through arterioles and venules. Erythrocytes are larger (approx. 8 um) than most capillaries (approx. 5 um), so they must deform greatly to squeeze through the lumen. There is no room for a slippage, or a cell-free layer. Thus, the Fahraeus-Lindqvist effect does not influence flow in capillaries.
Erythrocytes usually pass through capillaries single-file, although multi-file flow is observed. The cells may be folded, rolled-up, or be in a parachute configuration. When proceeding single-file, a bolus of plasma is trapped between the cells which may enhance diffusion. Tank treading, a repeated touching of the endothelial wall, is sometimes observed.
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