Foundations Practical - Week 1 to 8

The Embryonic Period

Development of Organs and Tissues

You have now been through the earliest stages of embryonic development. From the original simple trilaminar embryo all the organs and tissues will now begin to develop, details of these processes require more time than we currently have available. What we will now look at are the changes in the external embryo appearance during this period.

Key features to note are:

changes in overall size (CRL)
surface bulges that reflect organ development
development of the upper and lower limbs
development of the head

This page is about getting an overview of the external changes that occur during the embryonic period. In order to observe and understand the internal changes occuring in organ development is beyond the scope of this current practical.

Changes in Overall Size

In the first 8 weeks the embryo grows from 0.1 mm to about 3 cm in length.

Actual Size

Enlarged Size

During this time the embryo size is also measured from "crown" to "rump" or the Crown Rump Length (CRL).

Surface Bulges Reflect Organ Development

Surface of the Stage 13 Embryo showing surface features reflecting surface and internal development. Carnegie stage 13

Links: Embryonic Development | Carnegie stage 13

Placentation

During this period the parts of the conceptus not contributing to the embryo will contribute the fetal component of the placenta and the embryonic/fetal membranes.

This topic will also be covered in detail in BGD.

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers

Cite this page: Hill, M.A. (2024, April 16) Embryology Foundations Practical - Week 1 to 8. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Foundations_Practical_-_Week_1_to_8

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