Document Detail

Placentation in the Amazonian manatee (Trichechus inunguis).
MedLine Citation:
PMID:  18462617     Owner:  NLM     Status:  MEDLINE    
Evidence from several sources supports a close phylogenetic relationship between elephants and sirenians. To explore whether this was reflected in similar placentation, we examined eight delivered placentae from the Amazonian manatee using light microscopy and immunohistochemistry. In addition, the fetal placental circulation was described by scanning electron microscopy of vessel casts. The manatee placenta was zonary and endotheliochorial, like that of the elephant. The interhaemal barrier comprised maternal endothelium, cytotrophoblasts and fetal endothelium. We found columnar trophoblast beneath the chorionic plate and lining lacunae in this region, but there was no trace in the term placenta of haemophagous activity. The gross anatomy of the cord and fetal membranes was consistent with previous descriptions and included a four-chambered allantoic sac, as also found in the elephant and other afrotherians. Connective tissue septae descended from the chorionic plate and carried blood vessels to the labyrinth, where they gave rise to a dense capillary network. This appeared to drain into shorter vessels near the chorionic plate. The maternal vasculature could not be examined in the same detail, but maternal capillaries ran rather straight and roughly parallel to the fetal ones. Overall, there is a close resemblance in placentation between the manatee and the elephant.
A M Carter; M A Miglino; C E Ambrosio; T C Santos; F C W Rosas; J A d'Affonseca Neto; S M Lazzarini; A F Carvalho; V M F da Silva
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Reproduction, fertility, and development     Volume:  20     ISSN:  1031-3613     ISO Abbreviation:  Reprod. Fertil. Dev.     Publication Date:  2008  
Date Detail:
Created Date:  2008-05-08     Completed Date:  2008-08-07     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8907465     Medline TA:  Reprod Fertil Dev     Country:  Australia    
Other Details:
Languages:  eng     Pagination:  537-45     Citation Subset:  IM    
University of Southern Denmark, JB Winsloewsvej 21, DK 5000 Odense, Denmark.
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MeSH Terms
Animals, Newborn
Extraembryonic Membranes / anatomy & histology,  blood supply
Placenta / anatomy & histology,  physiology,  ultrastructure
Placental Circulation / physiology
Placentation / physiology*
Pregnancy, Animal*
Trichechus inunguis / physiology*
Umbilical Cord / ultrastructure

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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