2. Transition : after 3 weeks of fertilization a
process called gastrulation takes place this
comes from 3 cells
3. Ectoderm- is the outer layer it forms the
embryo’s skins and central nervous system.
Endoderm-is the inner layer it forms the lungs
and digestive track
Mesoderm- is the middle layer forms most of the
other organs.
4. During the first week membranes form and
protects the embryo as well nourishes it.
the amino membrane forms the fluid like sac.
The yolk sac membrane contains no yolk and
produces first blood and eventually turns into
gametes
Chorion turns into the embryos potion of the
placenta
Allantois forms the part of the umbilical cord
that connects the embryo to the placenta.
5. During week 12-23
The fetus length expands to 25 cm. and weight 0.5
kg. they start developing eyebrows and eyelashes
with a face of an infant .
At this point the heart beat can be heard and
fetus can be active. The mother can feel flutters
pokes and kicks.
6. Form into a fetal position
Sex of fetus is apparent
Baby skeletons develops bones
Baby begins to hear
Fingerprints and footprints form
7. Week 24-40
Baby's eyes open
Baby bones are fully developed
baby's central nervous system has matured to
the stage where it can control body
temperature
Baby's fingernails grow
Rapid gain weight begins
Week 40 your due date arrives