ASA Meeting 2013 - Placenta

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Placenta Embryology and Circulation

Australian Sonographers Association (ASA) Annual Conference 2013

Educate Innovate Celebrate

May 17 to 19 May 2013
ASA meeting2013 logo.jpg



Links: Conference Homepage | Sonographers Association | Placenta Development | Embryology

Draft Page - notice removed when complete.


Introduction

This page will be updated and contain the final conference presentation.

Abstract

Dr Mark Hill

Sonographic analysis of the placenta and uterus and their associated blood flow are key diagnostic prenatal assessments in human development. This review will provide an overview of the basic biology of the placentation process and key events in the developmental timeline. This talk should be of value to those wanting a better understanding of the process of human haemochorial placentation.


Placentation begins at the implantation site in the second week of development (GA week 4) with conceptus trophoblast cells invading the maternal endometrial epithelium and stroma. From that time on the process of placentation involves complex interactions between maternal uterine and fetal tissues. While there are many animal models of this process, none currently exactly match that seen in humans.


Maternally, these changes include modification of the maternal vascular, endocrine and immune response. Fetally, an entire organ is grown from extra-embryonic tissue that has many functions outside of acting as a simple exchange tissue. The main maternal vascular changes include increased vascularity and trophoblast modification of spiral arteries. The fetal vascular bed consists of large cord vessels and an exponentially growing capillary bed consisting of kilometres of villous capillaries. Identification of cord vessel number, size and blood flow, are important indices of normal fetal development. Furthermore extensive remodeled of the capillary bed occurs throughout development, with some villi morphologies influencing the efficiency of diffusional gas exchange. Clinically, abnormalities of placentation site, placental development, function and blood flow can have both maternal and fetal ramifications.


The full presentation and additional information/resources/links is available online (http://embryology.med.unsw.edu.au/embryology/index.php?title=ASA_Meeting_2013_-_Placenta).



Spiegel1626 table07.jpg

Historic drawing of Fetus and Placenta

Table 7 De formato foetu liber singularis (1626) by Adriaan van den Spiegel (1578-1625)

Embryo GA Week 4 (Week 2)

<mediaplayer width='250' height='260' image="http://embryology.med.unsw.edu.au/embryology/images/a/a9/Week2_001_icon.jpg">File:Week2_001.mp4</mediaplayer>
Week2 001 icon.jpg

This animation shows the process of implantation, occurring during week 2 of development in humans.

The beginning of the animation shows adplantation to the the uterus lining (endometrium epithelium). The hatched blastocyst with a flat outer layer of trophoblast cells (green), the inner cell mass which has formed into the bilaminar embryo (epiblast and hypoblast) and the large fluid-filled space (blastocoel).

  • green cells - trophoblast layer of the conceptus
  • blue cells - epiblast layer of the bilaminar embryo
  • yellow cells - hypoblast layer of the bilaminar embryo
  • white cells - uterine endometrium epithelium
  • red - maternal blood vessel


Implantation Movie Links: MP4 version | Week 2 Chorionic Cavity Movie | Implantation | Week 2 | Trophoblast | Human Chorionic Gonadotropin | Placenta Development | Movies

Embryo GA Week 9 (Week 7)

Stage18 bf10.jpg Stage18 bf11.jpg
Embryo in gestational sac Embryo open sac
Stage18 bf12.jpg Stage18 bf13.jpg
Embryo with placentation (ectopic) Embryo in amniotic sac


Placenta Vasculature - MRI and CT

Term placenta viewed from the fetal side.[1]

Human placenta vascular 01.jpg

Magnetic Resonance Angiography (MRA) Computed Tomography Angiography (CTA)
Legend
  • CA - chorionic artery
  • PSA - primary stem artery
  • SSA - secondary stem artery
  • TSA - tertiary stem artery


References

  1. <pubmed>20226038</pubmed>| BMC Physiol.


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Cite this page: Hill, M.A. (2024, March 28) Embryology ASA Meeting 2013 - Placenta. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/ASA_Meeting_2013_-_Placenta

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G