AJP - Regulatory, Integrative and Comparative Physiology, Vol 256, Issue 1 29-R34, Copyright © 1989 by American Physiological Society
Morphological dynamics of ureteral transport. II. Peristaltic patterns in relation to flow rate
L. Ohlson
Department of Radiology, Karolinska Hospital, Stockholm, Sweden.
To study in the human the conditions for the flow regimes inherent in
urinary systems with a dependence of the contraction interval on urine flow
rate (boluses-in-contact, leaky-bolus, and open-tube flow regimes), 50
urinary systems were examined at low and high flow rates. Morphometry and
volumetry were applied to eight urinary systems. The bolus frequently
contacted the preceding contraction ring but the mechanisms differed
categorically from that conventionally postulated. Thus the contraction
interval proved independent of flow rate, leading to boluses in contact not
only at high but also at low flow rates, which is impossible in
flow-dependent urinary systems. Likewise, contact proved possible with
small as well as large boluses. Furthermore, the contact was invariably
interrupted at the points of resistance to flow, the total contact period
being only 4% of the ureteral transit. Leaky-bolus flow and open-tube flow
were absent. The flow regimes as conventionally defined thus proved to be
absent from and inconsistent with normal human urinary transport.
