These studies explore the distribution of blood flow among small samples of placental tissue. Labeled microspheres (14 ± 1 pm) were Injected Into the left ventricle of six un-anesthetized ewes and Into the jugular vein of the fetus In utero. A total of 3,576 samples weighing 31. +11. (S.D.) mg were taken from seventeen cotyledons and counted for flow labels. Maternal and fetal flow within the cotyledons were both normally distributed with standard deviations of 44%. The maternal/ fetal flow ratio was less than 0.5 In 9% of the cotyledon, between 0.5 and 1.5 In 70%, and greater than 1.5 In 21%. Errors due to the method were estimated to contribute less than 10% of the flow variances. Maternal and fetal flows were significantly correlated (r = 0.57, p < .001). Spatial flow patterns were visualized using computerized Image processing. The distribution of maternal and fetal flow may be a sensitive determinant of water transfer, and the distribution of their ratio explains about 50% of the uterine—umbilical venous oxygen tension gradient. Analysis of the correlation between samples vs. the distance separating them suggested a weight of roughly 125 mg for hypothetical placental regulatory units.
Bioinformatics & Computational Biology
Ivan R. Neilsen
Gordon G. Power
C. Duane Zimmerman
S. Andrew Yakush
Paul Y. Yahiku
Master of Science (MS)
Year Degree Awarded
Date (Title Page)
Library of Congress/MESH Subject Headings
Maternal-Fetal Exchange; Fetal Blood; Placenta
Loma Linda University Libraries
This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Power, Gordon G.; Dale, P. Steven; and Nelson, Paul S., "Distribution of Maternal and Fetal Blood Flow within Cotyledons of the Sheep Placenta" (1980). Loma Linda University Electronic Theses, Dissertations & Projects. 1194.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives