Day 1

Day 1

Major Growth Developments

• 18 hours: The alimentary tract appears.
• 19 hours: The brain crease begins to form.
• 20 hours: Somites appear.
• 21 hours: The brain and nervous system begin to form.
• 22 hours: The head fold begins to form.
• 23 hours: Blood islands appear.
• 24 hours: The eyes begin to form.

Information & Image from the University of Illinois webpage: http://chickscope.beckman.uiuc.edu/explore/embryology/