SUMMARY
-The embryonic period of the ectodem, mesodem and endoderm periods form the tissues and organ systems of each
-Ectoderm layer; peripheral nervous system, sensory epithelium of ears, nose and eyes, skin, including nails and hair, sweat glands, mammary glands and tooth enamel.
-Mesoderm layer; paraaxial mesoderm (somitomeres: sclerotome, myotome and dermatome), vascular system (heart blood cells and blood vessels), urogenital system (kidney, gonads and ducts), spleen and adrenal cortex.
-Endoderm layer; form the epithelial lining (gastrointestinal tract, respiratory tract and bladder, pancreas, liver parenchyma, thyroid and parathyroid), epithelial lining of the tympanic cavity and auditory tube.
