CHAPTER 11 Flashcards
_________ is a crucial process in embryonic development, involving the creation of a mesodermal layer between the endoderm and ectoderm.
Gastrulation
It extends beneath the neural tube, forming bands of mesodermal cells on either side.
notochord
3 major compartments of somite
Sclerotome
Myotome
Dermomyotome
Forms the vertebrae and rib cartilage
Sclerotome
Forms the musculature back, rib cage and ventral body dome.
Myotome
Contains skeletal muscle progenitor cells and cells that generate the dermis of the back
Dermamyotome
Arises from the most dorsal sclerotome that generates tendons
Syndetome
Forms from the internal cells of the sclerotome
Arthronome
Somitogenesis have 5 important components
Periodicity
Fissure formation
Epithelialization
Specification
Differentiation
Somite formation begins as paraxial mesoderm cells become organized into whorls of cells, sometimes called ________
somitomeres
Because individual embryos in any species can develop at slightly different rates the number of _____ present is usually the best indicator of how far development has proceeded.
somites
It is a “clock and wave” mechanism, involving Notch and Wnt pathways and a rostral-to-caudal gradient.
Somite formation
Somites appear at the same time on both sides of the embryo, and the clock for formation is set when cells first enter the __________.
presomitic mesoderm
Somite formation starts from the _______ and proceeds rostrally if the presomitic mesoderm is inverted.
caudal end
It is biological process that regulates the development of an organism. It plays a crucial role in embryonic development.
Segmentation clock
It is a protein that plays a critical role in cell growth, differentiation, and migration. In the context of the segmentation clock, it’s thought to regulate a Wnt oscillating clock.
Fibroblast growth factor
It is a complex network of proteins best known for their roles in embryogenesis and cancer.
Wnt signalling
It is a highly conserved pathway that regulates cell-cell interactions crucial to multiple cell differentiation processes.
Notch signaling
_______, which can have hundreds of somites, have the same FgfB and Wnt waves and Notch clockwork as chicks and mice.
Snake embryos
Within this tissue, two critical players emerge: the Eph tyrosine kinases and their ligands, the ephrin proteins.
Unsegmented mesoderm
• In zebrafish, the boundary between the most recently separated somite and the presomitic mesoderm forms at the _____/_____ border.
• Chick embryos also exhibit restricted _____ expression in the boundary area.
ephrin B2/Eph A4
Eph A4
• After somitic fission, the cells of the newly formed somite are randomly organized as a _______.
• The receptor tyrosine kinase EphA4 and its ligand, ephrin B2, play a crucial role in ________
• mesenchymal mass
• somite development