Download Embryology Powerpoint File

mitosis
cleavage
mitosis
cleavage
solid ball of cells
Morula is
Latin for
mulberry
result of early cleavages
takes about 96 hours
hollow ball of cells
day 6 of development
On top is the inner cell mass where
the embryonic stem cells are
•lots of telomerase; “immortal”
Once the blastula reaches several hundred cells, the
embryo indents and becomes 3-layered (germ layers)
endoderm- inner layer
ectoderm- outer
mesoderm- middle
week 7-8
laser clip 1
laser clip 2
•the changing of unspecialized cells into 210 different types of cells, tissues, organs
•occurs during gastrula phase; when the cells become “different”
•endoderm becomes liver, pancreas, lining of organs
•mesoderm becomes muscles, skeleton, circ. Sys.
•ectoderm becomes skin, nervous sys., hair, nails
Increase in size and/or # of cells
embryonic
devel clip
differentiation
link
fertilization
cleavage/mitosis
cleavage/mitosis
differentiation/
gastrulation
differentiation
growth
Stem cells- undifferentiated cells that have the ability to
become specialized cells
*totipotent
a. Adult stem cells
•Some adult tissues contain stem cells:
brain, bone marrow, blood, vessels, muscle, skin, liver
•these cells give rise to “like” cells (liver liver)
•hoped to be used to treat Parkinson’s, diabetes, etc.
b. Embryonic stem cells
•grown from in-vitro fertilized eggs (controversial)
•taken from the 4-6 day old blastula
•toti/pluripotent- Can become (potentially) ANY type of
cell. They can truly differentiate
downside: abundance of telomerase may lead to….. cancer
also destroys the embryo
cord blood…stem cells
internal
internally
uterus
yolk
the mother/placenta
internally
yolk
combination of
maternal & embryonic tissues
materials exchanged by diffusion
blood supplies don’t mix
contains blood vessels
attaches embryo to placenta
yolk
externally
pouch