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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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Fetal membranes of the tucuxi, Sotalia fluviatilis (A, C-D) and the boto, Inia geoffrensis (B). (A) The inner surface of the amnion (arrow) is lined by simple cuboidal epithelium. The outer mesothelium forms a simple squamous epithelium. H.E. (B) Folds of allanto-amnion with an area of extensive squamous metaplasia H.E. (C) Area of squamous metaplasia found close to the placenta showing macrophages (arrows) within the tissue. H.E. (D) Allantochorion from an area with poorly developed villous trees and short villi. H.E. Scale bars = 50 μm (A, C), 200 μm (B) 500 μm (D).
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Figure 3: Fetal membranes of the tucuxi, Sotalia fluviatilis (A, C-D) and the boto, Inia geoffrensis (B). (A) The inner surface of the amnion (arrow) is lined by simple cuboidal epithelium. The outer mesothelium forms a simple squamous epithelium. H.E. (B) Folds of allanto-amnion with an area of extensive squamous metaplasia H.E. (C) Area of squamous metaplasia found close to the placenta showing macrophages (arrows) within the tissue. H.E. (D) Allantochorion from an area with poorly developed villous trees and short villi. H.E. Scale bars = 50 μm (A, C), 200 μm (B) 500 μm (D).

Mentions: The amnion and allanto-amnion were avascular in both species. The inner surface of the amnion was covered by simple cuboidal epithelium, apparently with a brush border, and the outer surface with simple squamous epithelium (Figure 3A). Simple squamous epithelium also covered the surface of the allanto-amnion. There were large foci of squamous metaplasia at some places within the allanto-amnion (Figure 3B). They were also found near the chorioallantoic plate. They were invested with simple cuboidal or squamous epithelium and housed macrophages (Figure 3C).


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)

Fetal membranes of the tucuxi, Sotalia fluviatilis (A, C-D) and the boto, Inia geoffrensis (B). (A) The inner surface of the amnion (arrow) is lined by simple cuboidal epithelium. The outer mesothelium forms a simple squamous epithelium. H.E. (B) Folds of allanto-amnion with an area of extensive squamous metaplasia H.E. (C) Area of squamous metaplasia found close to the placenta showing macrophages (arrows) within the tissue. H.E. (D) Allantochorion from an area with poorly developed villous trees and short villi. H.E. Scale bars = 50 μm (A, C), 200 μm (B) 500 μm (D).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Fetal membranes of the tucuxi, Sotalia fluviatilis (A, C-D) and the boto, Inia geoffrensis (B). (A) The inner surface of the amnion (arrow) is lined by simple cuboidal epithelium. The outer mesothelium forms a simple squamous epithelium. H.E. (B) Folds of allanto-amnion with an area of extensive squamous metaplasia H.E. (C) Area of squamous metaplasia found close to the placenta showing macrophages (arrows) within the tissue. H.E. (D) Allantochorion from an area with poorly developed villous trees and short villi. H.E. Scale bars = 50 μm (A, C), 200 μm (B) 500 μm (D).
Mentions: The amnion and allanto-amnion were avascular in both species. The inner surface of the amnion was covered by simple cuboidal epithelium, apparently with a brush border, and the outer surface with simple squamous epithelium (Figure 3A). Simple squamous epithelium also covered the surface of the allanto-amnion. There were large foci of squamous metaplasia at some places within the allanto-amnion (Figure 3B). They were also found near the chorioallantoic plate. They were invested with simple cuboidal or squamous epithelium and housed macrophages (Figure 3C).

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