Placenta Development: Difference between revisions
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'''Links:''' [http://embryology.med.unsw.edu.au/Notes/placenta.htm original Placenta page] | '''Links:''' [http://embryology.med.unsw.edu.au/Notes/placenta.htm original Placenta page] | ||
==Placental Classification== | |||
Classification of placenta is on the basis of histological (microscopic) structural organization and layers between fetal and maternal circulation, giving 3 main groups: | |||
# '''Haemochorial''' - placenta where the chorion comes in direct contact with maternal blood (human) | |||
# '''Endotheliochorial''' - maternal endometrial blood vessels are bare to their endothelium and these comes in contact with the chorion. (dogs, cats) | |||
# E'''pitheliochorial''' - maternal epithelium of the uterus comes in contact with the chorion.considered as primitive (pigs, cows) | |||
The presence of these three differing types of placenta have also been used to describe the pattern mammalian evolution. See also Placental Layers | |||
==Additional Images== | ==Additional Images== | ||
Revision as of 23:07, 7 April 2010
Introduction
The placenta (Greek, plakuos = flat cake) named on the basis of this organs appearance. The placenta a mateno-fetal organ which begins developing at implantation of the blastocyst and is delivered with the fetus at birth.
During that 9 month period it provides nutrition, gas exchange, waste removal, endocrine and immune support for the developing fetus. (More? Placental Overview | Histology).
There are essentially 3 separate aortic/venous circulatory systems: umbilical, systemic and vitelline. The umbilical system is lost at birth, the vitelline contributes to the portal system and the systemic (embryonic) is extensively remodelled to fom the the cardiovascular system.
Links: original Placenta page
Placental Classification
Classification of placenta is on the basis of histological (microscopic) structural organization and layers between fetal and maternal circulation, giving 3 main groups:
- Haemochorial - placenta where the chorion comes in direct contact with maternal blood (human)
- Endotheliochorial - maternal endometrial blood vessels are bare to their endothelium and these comes in contact with the chorion. (dogs, cats)
- Epitheliochorial - maternal epithelium of the uterus comes in contact with the chorion.considered as primitive (pigs, cows)
The presence of these three differing types of placenta have also been used to describe the pattern mammalian evolution. See also Placental Layers
Additional Images
- Gray0031.gif
