Gastrulation and disc

• What is the outer cell mass made of during implantation?

  Trophoblast cells
• What are the two types of trophoblasts?

  Syncytiotrophoblasts and cytotrophoblasts

  
• What does the inner cell mass differentiate into?

  Embryoblast
• What are the two layers formed from the inner cell mass?

  Epiblast and hypoblast
• What is the significance of the amniotic cavity in embryonic development?

  • Forms during the differentiation of the epiblast
  • Provides a protective environment for the embryo
  • Facilitates movement and growth of the embryo
• What is the bilaminar disc composed of?

  Epiblast and hypoblast
• What process begins at week 3 of embryonic development?

  Gastrulation

  
• What is formed during gastrulation?

  Three germ layers

  
• What are the three germ layers formed during gastrulation?

  Ectoderm, mesoderm, endoderm

  
• What does the primitive streak establish in embryogenesis?

  Basic organization of the organism

  
• What does the primitive streak include?

  Groove, node, and pit
• What does the primitive node also refer to?

  Hensen’s Node
• How do the first cells through the primitive streak differentiate?

  They integrate and displace hypoblast cells

  
• What is the epithelial-mesenchymal transition (EMT)?

  Process where epithelial cells become mesenchymal cells

  
• How are tumors related to embryonic development?

  Tumors can corrupt normal developmental processes
• What are the derivatives of the primary germ layers?

  • Ectoderm: CNS, skin, sensory epithelia
  • Mesoderm: Connective tissues, muscles, heart
  • Endoderm: Epithelial lining of GIT, glands

  
• What are the body axes established during gastrulation?

  Anterior-posterior, dorsal-ventral, left-right
• What is the first step of morphogenesis?

  Gastrulation

  
• What does the ectoderm develop into?

  Skin and nervous system
• What does the mesoderm develop into?

  Muscle and bones
• What does the endoderm develop into?

  Epithelial lining of GIT and glands
• What is the role of the primitive streak in gastrulation?

  It initiates the formation of germ layers