2009 Lecture 8

This lecture is an introduction to the development and functions of the placenta.

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. Only recently have we begun to understand the many different functions this organ carries out in addition to its role in embryonic nutrition. This lecture follows on the concepts of cardiovascular development covered in the previous lecture.

Lecture Objectives

• Understanding of placental villi development
• Understanding of placental structure
• Understanding of placental functions
• Brief understanding of placental abnormalities

UNSW Embryology Links

• Lecture 8 2008
• System Notes
• Development Timeline

branched villi - or terminal villi, grow from sides of stem villi, region of main exchange, surrounded by maternal blood in intervillous spaces.

primary villi - week 2, first stage of chorionic villi development, trophoblastic shell cells (syncitiotrophoblasts and cytotrophoblasts) form finger-like extensions into maternal decidua.

secondary villi - week 3, second stage of chorionic villi development, extraembryonic mesoderm grows into villi, covers entire surface of chorionic sac

stem villi - or anchoring villi, cytotrophoblast cells attached to maternal tissue.

tertiary villi third stage of chorionic villi development, mesenchyme differentiates into blood vessels and cells, forms arteriocapillary network, fuse with placental vessels, developing in connecting stalk

References

Textbooks

• The Developing Human: Clinically Oriented Embryology (8th Edition) by Keith L. Moore and T.V.N Persaud
• Larsen’s Human Embryology by GC. Schoenwolf, SB. Bleyl, PR. Brauer and PH. Francis-West -

Additional Textbooks

• Before We Are Born (5th ed.) Moore and Persaud
• Essentials of Human Embryology
• Human Embryology Fitzgerald and Fitzgerald
• Human Embryology and Developmental Biology Carlson

Online Textbooks

• Developmental Biology by Gilbert, Scott F. Sunderland (MA): Sinauer Associates, Inc.; c2000 - Figure 11.30. Human embryo and placenta after 40 days of gestation | Figure 15.11. Transfer of oxygen from the mother to the fetus in human embryos | Formation of extraembryonic membranes | Figure 15.9. Circulatory system of the early avian embryo
• Molecular Biology of the Cell 4th ed. Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter New York and London: Garland Science; c2002 -

Search

• Bookshelf placenta | placental villi development |

• Pubmed placenta development | placenta | placental villi development |

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Cite this page: Hill, M.A. (2024, April 19) Embryology 2009 Lecture 8. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/2009_Lecture_8

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

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