This animation depicts the normal embryological development of the gastrointestinal tract.  The animation is narrated by Dr. Lindsey L. Jenny, Ph.D. Division of Human Anatomy, Department of Radiology.

The animation is derived from Keith L. Moore, T.V.N. Persaud, Mark G. Torchia, "Before We Are Born: Essentials of Embryology and Birth Defects", 8th edition. Elsevier, 2012. and is also available on YouTube at https://www.youtube.com/watch?v=cBSyOgjTGVU&t=315s.
For this version, the video is played at 0.5 its normal speed.