Chapter 27.3, Problem 1QC

Summary Introduction

To review:

Primitive streak and what does it establishes.

Introduction:

After the implantation of the blastocyst in the uterus, the embryonic period starts. It begins in the third week. During this stage, the conceptus is termed as an embryo and this period lasts up to 8 weeks. Before the process of gastrulation, the primitive streak develops.