Embryonic Development

What is the name for a fertilized oocyte?

Zygote

What is the labeled stage of embryonic development?

Oocyte

Label the stages of embryonic development and the features of specific stages

A. Oocyte

B. Zygote (fertilized egg)

C. Zona pellucida

D. 4-Cell Stage (Day 2)

E. Morula/Solid Ball of Cells (Day 3)

F. Early Blastocyst/Hollowed Morula with Fluid (Day 4)

G. Implanting Blastocyst

H. Trophoblast

I. Blastocyst Cavity

J. Embryoblast (Inner Cell Mass)

As the zygote divides into smaller and smaller cells, what are these cells called?

Blastomeres

Where are oocytes released from?

The ovaries

What stage would “Day 2” be referred to as?

4-Cell Stage

What stage would “Day 3” be referred to as?

Morula Stage

What stage would “Day 4” be referred to as?

Early Blastocyst

What stage would “Days 7-12” be referred to as?

Implanting Blastocyst

Label the structures of early embryonic developement

A. Bilayered Embryonic Disc

B. Epiblast

C. Hypoblast

D. Chorion

E. Amnion

F. Yolk Sac

G. Amniotic Sac

H. Primary Germ Layers

I. Ectoderm

J. Mesoderm

K. Endoderm

L. Allantois

What does the chorion go on to form?

The fetal portion of the placenta

Primary Germ Layers: What does the ectoderm layer develop into?

• Epidermis of Skin

• Epithelial Lining of Mouth and Anus

• Nervous System

Primary Germ Layers: What does the mesoderm layer develop into?

• Dermis of Skin

• Muscular System

• Skeletal System

What does the mesoderm migrate to do?

To form the umbilical cord

Primary Germ Layers: What does the endoderm layer develop into?

Epithelial Lining of:

• GI Tract

• Urinary Tract

• Respiratory Tract