Gastrulation is a major milestone in development. It is the process of forming a trilaminar (three-layered) embryo by creating the three germ layers (ectoderm, mesoderm, endoderm). These germ layers are the building blocks for forming the entire body. The term gastrulation means formation of the gastrula, which is the name of the three-layered embryo. Gastrulation takes place during week 3 of development. (Remember: week 3 = 3 layers.)

But before we get to the nitty gritty of gastrulation, let’s back up and review what happens in week 2 of development that sets the stage for this important process.

After listening to this Audio Brick, you should be able to:

• Define the term gastrulation, know when it occurs, and describe the process of forming the three germ layers and their orientation to each other.
• Describe the development and fates of ectoderm derivatives including surface ectoderm, neural tube, and neural crest and list the adult tissues that are derived from ectoderm.
• Describe the development and fates of each region of mesoderm, including paraxial, intermediate, and lateral, and list the adult tissues that are derived from mesoderm.
• Describe the development and fate of endoderm and list the adult tissues that are derived from endoderm.

You can also check out the original brick from our Reproductive collection, which is available for free.

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You will get 5 days of full access to our Rx360+ program, including nearly 800 Rx Bricks. After the 5-day period, you will still be able to access over 150 free bricks, including the entire collections for General Microbiology and Cellular and Molecular Biology.

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from our Musculoskeletal, Skin, and Connective Tissue collection, which is available for free.

Learn more about Rx Bricks by signing up for a free USMLE-Rx account: www.usmle-rx.com

You will get 5 days of full access to our Rx360+ program, including nearly 800 Rx Bricks. After the 5-day period, you will still be able to access over 150 free bricks, including the entire collections for General Microbiology and Cellular and Molecular Biology.