View this time-lapse movie of a conceptus starting at day 3. What is the first structure you see? At what point in the movie does the blastocoel first appear? What event occurs at the end of the movie?
Visit this site for a summary of the stages of pregnancy, as experienced by the pregnant person, and view the stages of development of the fetus throughout gestation. At what point in fetal development can a regular heartbeat be detected?
This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's permission.
Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute OpenStax.
Attribution informationAccess for free at https://openstax.org/books/anatomy-and-physiology-2e/pages/1-introduction
Access for free at https://openstax.org/books/anatomy-and-physiology-2e/pages/1-introduction
© Apr 8, 2026 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.