Lecture 18 Flashcards
Proliferation?
One cell divides into multiple cells
Differentiation
Cells become different from one another
Morphogenesis
-Cells change their shape and arrangment
Totipotent
every cell in the embryo can go on to make any cell in the body
Trophectoderm
Becomes placenta
Inner mast cell
Becomes fetus
Inner mast cell two lineages?
Epiblast(inside)
Primitive ectoderm(outside cells)
Hippo signalling pathway
Dtermines whether cells become trophectoderm or inner cell mass
Order of primitive streak cells?
-Endoderm
_mesoderm
-Ectoderm
Endoderm becomes?
-GI tract
-Lungs
Mesoderm becomes?
-Blood
-Bone
-Kidney
-Muscles
Ectoderm becomes?
-Skin
-CNS
-Pigment
Anterior vs Posterior
Anterior(head)
Posterior(feet)
Ventral vs Dorsal
Ventral(stomach)
Dorsal (back)
Purpose of axis?
Ensure the orgaqns end up in the right places
HOX genes?
interpret the different axes during gastrulation to make sure that organs end up in the correct places during development at the right time
Loss of UBx Genes vs Lots of Ubx genes?
Loss: Drosophila with two sets of wings(lose haltier segment)
Lots: No wings
T/F: HOX genes are arranged in chromosomes in the same order they are expressed in the body?
True
How are HOX genes in humans expressed?
-From most anterior to most posterior
Overexpression of HOXA10 in mice?
-All the vertebrae become lumbar
-No more ribs
Under expression of HOXA10 in mice?
-All the vertebrae become thoracic
-No more lumbar
HOX genes are conserved among species?
Ture
What gives rise to the CNS?
Neural tube which forms from the ectoderm
Dorsal/Ventral axis for CNS?
Heat/Pain and pressure come from dorsal side
Motor neurons are on the ventral side
Morphogen Gradient?
-Morphogens diffuse a signal the further from the signal the smaller the effect
BMP
-Signals from the dorsal side causes cells to differentiate to dorsal cells the closer they are to it
Shh
-Signals from the ventral side
BMP and Shh
Depending on the concentration of Shh and BMP surrounding a cell determines which transcription factors a cell will turn on
-This makes the different neurons of the CNS
Second and third trimester of pregnancy?
Makes everything bigger
How to increase size of fetus?
-Cells get bigger
-Cell division (more cells)
-Embryo modulates cell death preventing it
Later stages the pathway that controls proliferation
- YAP will not be phosphorylated by LATs1/2 and will move into the nucleus and turn on genes needed for proliferation of the embryo
