Embryology Akers Qs Flashcards
Blastocyst contains which 2 parts?
inner cell mass (ICM)
trophoblast
Cells in ICM split into….
Epiblast- embryo proper
Hypoblast- primary endoderm- yolk sac
What is the Primitive Streak?
first marker of craniocaudal axis
dorsal and caudal side of epiblast
cranial end becomes primitive node
How do we turn the 2 layer disc into a 3 layer disc?
Gastrulation
cells migrate through primitive groove and form endoderm and mesoderm and ectoderm
What is grastrulation?
process where 3 germ layers are formed through cell migration
What are the 3 ways in which cells can migrate through the epiblast?
through the node
near the node
away from node
Why is the method of migration in gastrulation important?
creates 3 different cell fates
How is the neural tube formed?
Dorsal ectoderm becomes neural plate
lateral edges elevate and become neural folds
mid region depresses and becomes neural groove
neural folds fuse together
What does the nonneural ectoderm become?
Skin
What does the neural ectoderm become?
brain and spinal cord (CNS)
What germ layer does the notochord come from?
Mesoderm
What is neurulation?
formation of neural tube
How do cells fuse during neurulation?
cells in middle of neural folds fuse first and zippers anteriorly and posteriorly at same time
What are cranial and caudal neuropores?
openings at ends of neural tube
How do birth defects or neural tube defects occur?
when the neuropores do not close correctly
How should women avoid neural tube defects?
consume more folic acid
What are the functions of the notochord?
defines body axis
provides rigidity to embryo
signaling center to induce neural fates
precursor for axial skeleton
Which germ layer forms the neural crest?
ectoderm
What are neural crest cells?
migratory cells that come from ectoderm and migrate throughout body to give rise to a number of cell fates
What are the 4 regions of Mesoderm?
axial- notochord
paraxial mesoderm- somites
intermediate mesoderm- kidney/ gonads
lateral plate mesoderm- lining of organ cavities
What are the derivatives of the endoderm?
gives rise to GI tract, epithelial lining of lung and trachea, liver, gall bladder, pancreas
