AJP - Regulatory, Integrative and Comparative Physiology, Vol 256, Issue 1 19-R28, Copyright © 1989 by American Physiological Society
Morphological dynamics of ureteral transport. I. Shape and volume of constituent urine fractions
L. Ohlson
Department of Radiology, Karolinska Hospital, Stockholm, Sweden.
Ureteral transport was studied in 50 urinary systems by urography with
video recording in the upright and recumbent positions using low-osmolality
and high-osmolality contrast media. Morphometry and volumetry were applied
to right urinary systems in which the urine-filled segments had a circular
cross section at maximum peristaltic distension. The filling of the lumbar
segment was composed of four fractions, each entering that segment by a
specific mechanism: 1) the residual urine left behind by the preceding
contraction ring, 2) the postcontraction injection from the pyelocalyceal
system, 3) the extraperistaltic flow, and 4) the peristaltic injection
produced by the pyelocalyceal contraction rings. The variations in the
precontraction filling by fractions 1-3 and in the volume of fraction 4
gave rise to four types of transport. The junction between the lumbar and
pelvic segments constituted a constant point of resistance to flow that
prevented fractions 1-3 from entering the pelvic segment, the peristaltic
injection into that segment being determined solely by the resistance at
the junction and the volume of the bolus in the lumbar segment.
Extraperistaltic flow to the bladder constituted a separate type of
transport.
