Early development (dave's notes) Flashcards
What are the stages of development from day 1 to day 6?
Zygote -> morula -> blastocyst -> implantation
What is the outer layer of the developing cell mass? What does this become?
Trophoblast, becomes placenta
What is the inner layer of the developing cell mass?
The inner cell mass -> amnion and yolk sac
What divides the amnion and yolk sac divided by? What three things does this give rise to?
The embryonic plate. This gives rise to ectoderm, primary mesoderm, and endoderm
What grows from ectoderm to endoderm?
The notochord is an axial rod of cells growing from ectoderm to endoderm
Where does the neural tube develop? What does this later form?
The neural tube develops on the ectodermal surface, which is later to form the brain and spinal cord
What does the neural crest develop from? What does this form?
Cells at the edges (of what?) become isolated and develop the neural crest which becomes posterior root ganglia, ganglia of cranial nerves and autonomic ganglia
How does mesoderm lie?
In three longitudinal strips
What does the mesodermal strip nearest the midline become?
Segments into mesodermal somites which
- produce sclerotome, which surrounds the neural tube and notochord -> becomes vertebrae and dura mater
- myotome producing muscles of the body wall
What does the intermediate strip of mesoderm produce?
The intermediate cell mass and becomes segmented
What does the lateral side of the intermediate cell mass become?
The lateral side develops the pronephros, mesonephros, and metanephros
What does the medial side of the intermediate cell mass become?
The gonad and cortex of the suprarenal gland
Other than the lateral and medial side, what develops from the intermediate cell mass?
The lateral plate which is unsegmented
Why does the embryo begin to curl up?
From increased dorsal growth relative to ventral growth
What happens to the lateral plate?
The lateral plage curls around enclosing the yolk sac.
