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Early Development: Three Germ Layers

Early Development: Three Germ Layers

Author: Nathan Lampson

This lesson will identify the three germ layers that form in an early embryo and the tissues and organs that develop from them.

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Terms to Know

After the morula forms, each new cell that divides is called a blastomere.

Cell Differentiation

The process of cells taking on specific forms and functions, also called specialization of cells.


A general term to describe the splitting or breaking apart of an object or molecule; in embryology this is when the zygote starts to divide into multiple cells.


The outer germ layer that forms the nervous system, skin, melanocytes and lenses of the eyes.


The innermost germ layer that forms the digestive tract, respiratory tract, endocrine glands, auditory systems, and urinary bladder.

Germ Layers

The first three layers of tissue that develops in the embryo as it starts to form (ectoderm, mesoderm, and endoderm).


The middle germ layer that forms muscles (cardiac, smooth, skeletal), mesenchyme, blood vessels, and mesenteries.


When an organism develops a specific shape.