Development of Animal Cells
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Transcript Development of Animal Cells
Development of Animal Cells
Aka…Embryology
Embryology
- study of the development of an embryo
5 major stages…
1. Gametogenesis - gamete production
2. Fertilization - gamete --> zygote
3. Cleavage - Zygote --> Blastula
4. Gastrulation - Blastula --> Gastrula
5. Organogenesis - Organ Formation
-i.e. Neurulation- Gastrula --> Neurula
Fertilization:
male and female gametes fuse to form a zygote
Funnel shaped end of
a Fallopian Tube is the
usual site for
fertilization
A sperm must penetrate
the egg
Now it is called a
ZYGOTE
Tiny cilia line the tube to
propel the fertilized egg
toward the uterus
Cleavage
(Process by which a zygote divides by mitosis to form 2 new cells)
Cell # doubles with
each division
(two cells will divide to
form ___ cells and so
on)
each cell smaller than
zygote
MORULA:
a zygote consisting of about 12-32 cells in a
solid ball
Reaches the uterus in about 3-4 days after
fertilization
BLASTULA formation
Cells start to compact and move
to the edge of the cell, leaving
a fluid-filled space in the
center- this will eventually form
the BLASTULA/Blastocyst
a.
b.
c.
a hollow ball of cells that forms
btwn 5-8 days after fertilization
This will attach to the lining of the uterus
cell division continues
Cells on 1 side of the blastocyst begin to
fold inward to form the gastrula
Gastrulation
Blastula (hollow ball of cells) transformed into the Gastrula (three-layered stage)
Gastrulation - sorts all the cells into distinct cell
layers (ectoderm, endoderm, and mesoderm)
Gastrulation forms 3 distinct tissue layers
Layer on the outer surface
of the gastrula is called the
ECTODERM
eventually forms the
SKIN and NERVOUS
tissue
ENDODERM
Layer on the INNER
SURFACE of the gastrula is
called the ENDODERM
ENDODERM eventually
develops into the lining of the
digestive tract and organs
associated with digestion
MESODERM
Mesoderm is the 3rd cell
layer found in the
developing embryo
between the ECTO and
ENDODERM (“meso”
means middle)
MESODERM Continues to
grow and divide and
eventually develops into
muscle cells, circulatory, and
excretory cells, bone cells
and respiratory system