Final answer:
Embryonic structures are classified according to the germ layer they originate from: ectoderm (epidermis, central nervous system, tooth enamel), mesoderm (dermis, lymphatic system, musculoskeletal system, cardiovascular system, reproductive system, urinary system), and endoderm (thyroid and parathyroid glands, respiratory tract linings, digestive tract linings, epithelial linings of oral cavity and rectum).
Step-by-step explanation:
Embryonic Germ Layer Classification
During embryonic development, the three primary germ layers differentiate to form various structures and organs within the body. Here is the classification of the listed structures according to their originating germ layer:
Ectoderm: 2. Epidermis, 3. Central nervous system, 12. Tooth enamel
Mesoderm: 1. Dermis, 5. Lymphatic system, 6. Musculoskeletal system, 7. Cardiovascular system, 9. Reproductive System, 10. Urinary system
Endoderm: 4. Thyroid and parathyroid glands, 8. Respiratory tract linings, 11. Digestive tract linings, 13. Epithelial linings of oral cavity and rectum
The ectoderm gives rise to the central and peripheral nervous systems, sensory organs, epidermis, hair, and nails. The mesoderm forms the skeleton, muscles, connective tissue, heart, blood vessels, and kidneys. The endoderm develops into the epithelial lining of the gastrointestinal tract, liver, and pancreas, as well as the lungs.