The anterior-posterior axis is established during the gastrulation process.  This imaginary axis line runs from the head to the tail, or in organisms without these structures, from the mouth to the anus.  

Anterior-Posterior Axis

The dorsal-ventral axis is established during the gastrulation process.  This imaginary axis line runs from the back to the belly, or the dorsum to the ventrum.  

Dorsal-Ventral Axis

The right-left axis is established during the gastrulation process.  This imaginary axis line separates the two lateral sides of the organism.   

Right-Left Axis

- anterior-posterior axis
- dorsal-ventral axis
- right-left axis

Michigan State University

Gastrulation occurs in embryogenesis after cleavage.  The blastomeres that make up the blastula extensively rearrange themselves to contain three germ layers: the endoderm, the mesoderm, and the ectoderm.  These three layers will give rise to all of the organs of the body.  After gastrulation, the embryo is said to be a gastrula.  

Gastrulation

Barresi, M. J., &amp; Gilbert, S. F. (2020). Developmental Biology (12th ed.). New York: Sinauer.

Developmental Biology (12th ed.)

The germ layers are the three layers of the embryo that are formed in the gastrulation process.  They give rise to all of the tissues of the body except for germ cells.  The layers include:

- endoderm
- mesoderm
- ectoderm

Learn Before

Related

Learn After