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

Foundations Practical: Introduction | Week 1 and 2 | Week 3 and 4 | Week 1 to 8 | Week 9 to 36 | Neonatal | Critical Periods | Additional Resources | Quiz

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

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Cite this page: Hill, M.A. (2024, April 19) 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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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G