Embryogenesis Flashcards
Cortical Reaction
- Cortical granules fuse with oolemma
- Granules release contents (enzymes) between oolemma and zona pellucida
The prechordal plate is also known as:
Buccopharyngeal membrane
-site of future mouth development
How does the prechordal plate form?
Small, disk-like thickening of hypoblast forms at the end of hte bilaminar embryonic disk
What is the result of gastrulation?
Trilaminar empbryo whose 3 layers are the embryonic endoderm, mesodem, and ectoderm. All layers derive from the epiblast cells.
When does the definitive yolk sac form?
When the endodermal cells divide and migrate around the yolk sac, they gradually replace the original hypoblast cells.
What does the notochord induce?
Neural plate, neural groove formation in the overlying ectoderm
Mesoderm’s three main regions?
paraxial, intermediate, lateral.
What does lateral plate split into?
Visceral and parietal layers
Definite yolk sac becomes?
Primitive gut tube
Histogenesis
Cell movement from undifferentiated to producing many different layers of tissue
Spina bifida
Epidermis does not form completely
Derivatives of Ectoderm
Dorsal root ganglion Sympathetic ganglia Peripheral nerves Schwann and satellite cells Adrenal medulla melanocytes
Derivatives of Mesoderm
Paraxial (somites-cartilage, bone, connective tissue of body and limbs)
Intermediate (Urogenital system)
Lateral Plate (Appendicular skeleton, tendons, ligaments, connective tissue of viscera and body wall)
Remnant of notochord
Nucleas polposus
(Paraxial) Somites Differentiation
Sclertotome- Cells migrate medially around notochord to form vertebral column
Dermatome: Cells migrate under ectoderm (epidermis) to form the dermis
Myotome: Cells divide into two groups, epaxial and hypaxial and form most skeletal muscles of the body
