Download Embryo Review Sheet

Embryology Review
1. Define embryology: ______________________________________________________________
2. There are four main processes to early embryonic development. Finish the statement about each
process.
(a) Fertilization: This is the process when the _____ and the sperm come together to form a
________.
(b) Implantation: This is the process when the blastocyst implants into the wall of the __________.
This implantation ensures that the baby will have a home for the next 9 monhts.
(c) Gastrulation: This is the process where the blastocyst folds in to become a ball of cells with
_____ layers. These layers are known as the germ layers.
(d) Cell differentiation: This is the process when the cells of the three germ layers are given specific
______. In other words, this is the time when stem cells become different from each other.
They become nerve cells, blood cells, muscle cells, etc.
3. When an embryo is going through the 4 processes from number 2, it takes on different shapes and
looks along the way. For each of the following stages of an embryo, explain its structure and draw a
picture of it.
(a) Zygote:
(b) Morula:
(c) Blastocyst:
(d) Gastrula:
4. Gastrulation: Below is an image of a gastrula. For each arrow, state the name of the germ layer
(endoderm, mesoderm, ectoderm) and state the types of cells that that layer will become.
5. Extraembryonic membranes are membranes around the growing embryo that do not become a part
of the baby, but instead help to nourish and protect baby during development. Complete the
statements about each extraembryonic membrane.
(a) Amnion: This membrane forms the _____________ ______, which is a fluid filled sac that
__________ the embryo.
(b) Chorion: This is the outer-most membrane that combines with the uterine lining to for the
_____________.
6. What is the placenta?
7. What is in vitro fertilization (IVF)?
8. What are stem cells?
9. What is the main goal of stem cell research?