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Placental vascular corrosion cast studies: A comparison between ruminants and humans
Author(s) -
Leiser Rudolf,
Krebs Christiane,
Ebert Brigitte,
Dantzer Vibeke
Publication year - 1997
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/(sici)1097-0029(19970701/15)38:1/2<76::aid-jemt9>3.0.co;2-s
Subject(s) - placenta , intervillous space , biology , human placenta , ruminant , fetus , blood flow , placentation , anatomy , physiology , pathology , medicine , pregnancy , ecology , genetics , crop
The microvasculature of both the ruminant placentomes of cattle, sheep, and goats and the human placenta were compared, using corrosion casts of blood vessels and scanning electron microscopy. The fetal vascular trees of ruminant and human placenta differ in form and size, which correlates with the degree of ramification; however, their architecture of stem, intermediate, and terminal villi is similar. In the human, the system of serially linked capillary convolutions of terminal villi is longer than that in ruminants. Therefore, in guaranteeing blood flow against flow resistance, the human vessels particularly need a straight course, anastomoses, and sinusoidal dilations. Specifically in the ruminants studied, the venous vessels outweigh the arterial ones by volume and by number. They are suggested to be absorptive for substances metabolized in the zone of the capillary complex. The most extreme interspecies difference relates to the maternal vasculature, which, in contrast to the fetal system, is a closed system in the ruminant septas and an open lacunal intervillous space in the human. Converging and differing morphological vascular phenomena of ruminants and human placenta are discussed in terms of maternofetal exchange related to placental efficiency. In summary, the ruminant placenta, concerning the fetal vascular tree, in many aspects is workable as a model for the human. Microsc. Res. Tech. 38:76–87, 1997. © 1997 Wiley‐Liss, Inc.