Embryogenesis and Germ Layers

Overview

• Gastrulation: Formation of three primary germ layers
  1. Endoderm
  2. Mesoderm
  3. Ectoderm

Germ Layers and Their Derivatives

Endoderm

• Forms the gastrointestinal (GI) tract
• GI Tract Representation: Tube with openings at both ends
• Develops into:
  • Upper GI Tract: Lungs and liver
  • Abdomen: Pancreas
  • Esophagus
  • Stomach
  • Small intestines
  • Large intestines

Mesoderm

• Tissues indicated in purple
• Develops into:
  • Some inner layers of the skin
  • Muscles and bones, including cardiac muscle
  • Kidneys
  • Bladder
  • Gonads (ovaries or testes)

Ectoderm

• Forms outer layer of skin and skin-related structures
• Develops into:
  • Skin
  • Sweat glands
  • Hair
  • Nervous system

Recap

• Endoderm: Forms GI and pulmonary systems (lungs, GI tract, liver, pancreas)
• Mesoderm: Forms muscles (including heart muscle), skeletal system, genitourinary tracts
• Ectoderm: Forms skin, skin-related structures, and nervous system