Section 2
First Week of Development
Book
Version 29
By Boundless
By Boundless
Boundless Anatomy and Physiology
Physiology
by Boundless
4 concepts
![Thumbnail](../../../../../../figures.boundless-cdn.com/6400/square/human-fertilization.jpg)
Fertilization
Fertilization occurs when a sperm and an egg have fused together to form a zygote, which begins to divide as it moves towards the uterus.
![Thumbnail](../../../../../../figures.boundless-cdn.com/6402/square/gray9.jpg)
Cleavage of the Zygote
The process of cleavage is the step of embryogenesis where the zygote divides to produce a cluster of cells known as the morula.
![Thumbnail](../../../../../../figures.boundless-cdn.com/5375/raw/blastocyst-english.jpg)
Blastocyst Formation
The blastocyst forms early in embryonic development and has two layers that form the embryo and placenta.
![Thumbnail](../../../../../../figures.boundless-cdn.com/1985/square/gray36.jpg)
Implantation
Implantation is the very early stage of pregnancy at which the embryo adheres to the wall of the uterus and begins to form the placenta.