Week 3 Embryology Flashcards
When is the critical time of development (early embryonic development)?
3rd-4th week
Embryogenesis
- formation and development of an embryo
- each embryo grows at a slightly different rate
When is the embryonic period?
3rd-8th week of gestation
What are the 3 germ layers?
- Endoderm
- Mesoderm
- Ectoderm
Endoderm becomes the …
GI tract, lungs, and endocrine system
Mesoderm becomes the …
muscle, skeleton, cardiovascular system, reproductive system
Ectoderm becomes the …
nervous system, skin, and hair
What is the major endocrine organ?
Pituitary (anterior and posterior lobes)
What type of tissue does the anterior pituitary develop from?
Ectoderm Tissue (Rathke’s pouch)
What type of tissue does the posterior pituitary develop from?
Neural Tissue (infundibulum)
What is the initial step of sexual differentiation?
fertilization
Primordial germ cells
- develop in the embryo
- migrate to the gonadal ridge in the 6th week of development
- arrival at the gonadal ridge stimulates formation of primitive sex cords
What types of ducts are present in the early embryo?
Mesonephric and Paramesonephric Ducts
What is critical for sexual differentiation?
Y chromosome
What duct remains in the male?
Mesonephric (Wolffian) ducts
