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Placentation in dolphins from the Amazon River Basin: the Boto, Inia geoffrensis, and the Tucuxi, Sotalia fluviatilis.

da Silva VM, Carter AM, Ambrosio CE, Carvalho AF, Bonatelli M, Lima MC, Miglino MA - Reprod. Biol. Endocrinol. (2007)

Bottom Line: However, there were also areolar regions with tall columnar trophoblast and these were more sparsely supplied with capillaries.The endometrium was well vascularised and richly supplied with actively secreting glands.These findings are consistent with the current view that Cetacea are nested within Artiodactyla as sister group to the hippopotamids.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Institute of Amazonian Research, Manaus, AM, Brazil. tucuxi@inpa.gov.br

ABSTRACT
A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched to supply a bilobed allantoic sac. Small blood vessels and smooth muscle bundles were found within the stroma of the cord. Foci of squamous metaplasia occurred in the allanto-amnion and allantochorion. The interhemal membrane of the placenta was of the epitheliochorial type. Two different types of trophoblastic epithelium were seen. Most was of the simple columnar type and indented by fetal capillaries. However, there were also areolar regions with tall columnar trophoblast and these were more sparsely supplied with capillaries. The endometrium was well vascularised and richly supplied with actively secreting glands. These findings are consistent with the current view that Cetacea are nested within Artiodactyla as sister group to the hippopotamids.

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Umbilical cord of the tucuxi, Sotalia fluviatilis. Shown are part of the urachus and the paired umbilical veins with their vasa vasorum. The stroma is supplied with small blood vessels and contains bundles of smooth muscle (sm). Masson's triple stain. Scale bar = 500 μm.
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Figure 1: Umbilical cord of the tucuxi, Sotalia fluviatilis. Shown are part of the urachus and the paired umbilical veins with their vasa vasorum. The stroma is supplied with small blood vessels and contains bundles of smooth muscle (sm). Masson's triple stain. Scale bar = 500 μm.

Mentions: The principal features of the cord are shown in Figure 1. Most of the surface was covered by simple squamous epithelium. The surface accretions were plaques of squamous metaplasia (Figure 2A). They were invested with stratified squamous epithelium (Figure 2B) and sometimes contained macrophages. The urachus was lined with transitional epithelium. The major umbilical vessels, veins as well as arteries, were endowed with vasa vasorum. The stroma of the cord was supplied with small blood vessels (Figure 2C). Smooth muscle bundles were seen within the stroma at some distance from the tunica media of the major vessels (Figure 2D) and running longitudinal to the cord.


Placentation in dolphins from the Amazon River Basin: the Boto, Inia geoffrensis, and the Tucuxi, Sotalia fluviatilis.

da Silva VM, Carter AM, Ambrosio CE, Carvalho AF, Bonatelli M, Lima MC, Miglino MA - Reprod. Biol. Endocrinol. (2007)

Umbilical cord of the tucuxi, Sotalia fluviatilis. Shown are part of the urachus and the paired umbilical veins with their vasa vasorum. The stroma is supplied with small blood vessels and contains bundles of smooth muscle (sm). Masson's triple stain. Scale bar = 500 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1919380&req=5

Figure 1: Umbilical cord of the tucuxi, Sotalia fluviatilis. Shown are part of the urachus and the paired umbilical veins with their vasa vasorum. The stroma is supplied with small blood vessels and contains bundles of smooth muscle (sm). Masson's triple stain. Scale bar = 500 μm.
Mentions: The principal features of the cord are shown in Figure 1. Most of the surface was covered by simple squamous epithelium. The surface accretions were plaques of squamous metaplasia (Figure 2A). They were invested with stratified squamous epithelium (Figure 2B) and sometimes contained macrophages. The urachus was lined with transitional epithelium. The major umbilical vessels, veins as well as arteries, were endowed with vasa vasorum. The stroma of the cord was supplied with small blood vessels (Figure 2C). Smooth muscle bundles were seen within the stroma at some distance from the tunica media of the major vessels (Figure 2D) and running longitudinal to the cord.

Bottom Line: However, there were also areolar regions with tall columnar trophoblast and these were more sparsely supplied with capillaries.The endometrium was well vascularised and richly supplied with actively secreting glands.These findings are consistent with the current view that Cetacea are nested within Artiodactyla as sister group to the hippopotamids.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Institute of Amazonian Research, Manaus, AM, Brazil. tucuxi@inpa.gov.br

ABSTRACT
A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched to supply a bilobed allantoic sac. Small blood vessels and smooth muscle bundles were found within the stroma of the cord. Foci of squamous metaplasia occurred in the allanto-amnion and allantochorion. The interhemal membrane of the placenta was of the epitheliochorial type. Two different types of trophoblastic epithelium were seen. Most was of the simple columnar type and indented by fetal capillaries. However, there were also areolar regions with tall columnar trophoblast and these were more sparsely supplied with capillaries. The endometrium was well vascularised and richly supplied with actively secreting glands. These findings are consistent with the current view that Cetacea are nested within Artiodactyla as sister group to the hippopotamids.

Show MeSH
Related in: MedlinePlus