Medicine & USMLE

Mesoderm Derivatives

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Germ Layer Derivatives
  1. Ectoderm Derivatives
  2. Mesoderm Derivatives
  3. Endoderm Derivatives

Summary

The mesoderm is the middle layer of the developing embryo. The most prevalent mesoderm derivatives are the skeletal system of muscles, bones, and cartilage. Other key mesoderm derivatives include the heart and blood vessels of the circulatory system, the notochord, the adrenal cortex, the dermis of the skin, the kidneys, and the gonads of the urogenital system.

Key Points

  • Mesoderm = middle germ layer in embryonic development (“meso” = middle)
    • Gives rise to tissues in the “middle”
  • Mesoderm Derivatives
    • Paraxial mesoderm gives rise to muscle, cartilage, bone, dermis of skin
    • Axial mesoderm gives rise to notochord
      • releases signals for neurulation in development
      • remnant is nucleus pulposus in spinal disks
    • Intermediate mesoderm gives rise to kidneys, gonads, adrenal cortex
      • Note: not the urethra and bladder (from endoderm), and not adrenal medulla (from ectoderm)
    • Lateral plate mesoderm develops into circulatory system (heart and blood vessels)