Embryogenesis and Germ Layer Development

Introduction

• Gastrulation: A key process in early embryogenesis leading to the formation of three primary germ layers.

Three Primary Germ Layers

1. Endoderm
   • Forms the gastrointestinal tract (GI tract).
   • Develops into structures such as:
     • Lungs (from the upper GI tract)
     • Liver
     • Pancreas
     • Esophagus
     • Stomach
     • Small intestines
     • Large intestines
2. Mesoderm
   • Forms some inner layers of the skin.
   • Develops into:
     • Muscles, including cardiac muscle
     • Bones
     • Kidneys
     • Bladder
     • Ovaries/Testes
3. Ectoderm
   • Forms the outer layer of skin.
   • Develops into skin-related structures such as:
     • Sweat glands
     • Hair
   • Also forms the nervous system.

Summary

• Endoderm: Develops into the gastrointestinal and pulmonary systems including lungs and GI tract organs.
• Mesoderm: Develops into muscles, heart muscle, skeletal system, and genitourinary tracts.
• Ectoderm: Develops into skin, related structures, and the nervous system.