Embryology

6.

Fourth to Eighth Week

6.1.

Overview of the Embryonic Period

6.1.1.

Critical Periods of Organogenesis

6.1.2.

Susceptibility to Teratogens

6.2.

Folding of the Embryo

6.2.1.

6.2.2.

6.2.3.

6.2.4.

Formation of the Body Shape

6.2.5.

Incorporation of the Yolk Sac

6.3.

Derivatives of the Ectoderm

6.3.1.

Surface Ectoderm

6.3.1.1.

6.3.1.2.

6.3.1.3.

6.3.1.4.

6.3.1.5.

Lens of the Eye

6.3.1.6.

Enamel of Teeth

6.3.2.

6.3.2.1.

6.3.2.1.1.

6.3.2.1.2.

6.3.2.2.

6.3.2.2.1.

Sensory Ganglia

6.3.2.2.2.

Autonomic Ganglia

6.3.2.2.3.

6.3.2.2.4.

6.3.2.2.5.

Craniofacial Cartilage and Bone

6.4.

Derivatives of the Mesoderm

6.4.1.

Paraxial Mesoderm

6.4.1.1.

6.4.1.2.

Skeletal Muscles

6.4.1.3.

6.4.2.

Intermediate Mesoderm

6.4.2.1.

6.4.2.2.

6.4.3.

Lateral Plate Mesoderm

6.4.3.1.

6.4.3.1.1.

6.4.3.1.2.

6.4.3.2.

Splanchnic Layer

6.4.3.2.1.

6.4.3.2.2.

6.4.3.2.3.

Smooth Muscle of Gut

6.4.3.3.

Formation of Body Cavities

6.5.

Derivatives of the Endoderm

6.5.1.

Primitive Gut Tube

6.5.1.1.

6.5.1.1.1.

6.5.1.1.2.

6.5.1.1.3.

6.5.1.1.4.

Proximal Duodenum

6.5.1.2.

6.5.1.2.1.

Distal Duodenum

6.5.1.2.2.

6.5.1.2.3.

6.5.1.2.4.

6.5.1.2.5.

6.5.1.2.6.

Ascending Colon

6.5.1.2.7.

Proximal Transverse Colon

6.5.1.3.

6.5.1.3.1.

Distal Transverse Colon

6.5.1.3.2.

Descending Colon

6.5.1.3.3.

6.5.1.3.4.

6.5.1.3.5.

Upper Anal Canal

6.5.2.

Pharyngeal Apparatus

6.5.2.1.

Pharyngeal Arches

6.5.2.1.1.

6.5.2.1.2.

6.5.2.1.3.

6.5.2.1.4.

6.5.2.2.

Pharyngeal Pouches

6.5.2.3.

Pharyngeal Grooves

6.5.2.4.

Pharyngeal Membranes

6.6.

Development of Major Organ Systems

6.6.1.

Nervous System Development

6.6.1.1.

6.6.1.1.1.

6.6.1.1.2.

6.6.1.1.3.

6.6.1.2.

6.6.1.3.

Peripheral Nervous System

6.6.2.

Cardiovascular System Development

6.6.2.1.

6.6.2.2.

Heart Septation

6.6.2.3.

Formation of Heart Chambers

6.6.2.4.

6.6.2.5.

Vitelline Vessels

6.6.2.6.

Umbilical Vessels

6.6.2.7.

Fetal Circulation

6.6.3.

Musculoskeletal System Development

6.6.3.1.

6.6.3.2.

Appendicular Skeleton

6.6.3.3.

6.6.4.

Respiratory System Development

6.6.4.1.

6.6.4.2.

6.6.4.3.

6.6.4.4.

6.6.5.

Digestive System Development

6.6.5.1.

6.6.5.2.

6.6.5.3.

6.6.5.4.

6.6.5.5.

6.6.5.6.

6.6.6.

Urogenital System Development

6.6.6.1.

6.6.6.1.1.

6.6.6.1.2.

6.6.6.1.3.

6.6.6.2.

6.6.6.2.1.

6.6.6.2.2.

6.6.6.3.

6.6.6.4.

External Genitalia

6.6.7.

Head and Neck Development

6.6.7.1.

6.6.7.2.

6.6.7.3.

6.6.7.4.

6.6.7.5.

6.6.8.

Limb Development

6.6.8.1.

6.6.8.2.

Apical Ectodermal Ridge

6.6.8.3.

6.6.8.4.

6.6.9.

Integumentary System Development

6.6.9.1.

6.6.9.2.

6.6.9.3.

Skin Appendages

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7. The Fetal Period