EMbryonic period Flashcards
When does the embryonic period start?
When implantation is complete
What is the embryonic period and how long is it?
-It is a time of major structural development
-Growth that continues until 2 months after conception
The term embryo comes from the Greek word. What does it mean?
Swell
Cells that form the supporting structures differentiate into____, a disk-shaped mass of supporting tissue;
the placenta
a “rope” of tissue that contains two arteries and a vein that connect from the placenta to the developing child
umbilical cord
a membrane filled with watery amniotic fluid
amniotic sac,
What are the structures formed during the structural development
-Placenta
-umbilical cord
-amniotic sac
Why is the placenta so important?
It provides for the exchange of nutrients and waste products between mother and embryo.
-serves as a filter
What doesn’t cross the placental barrier?
Larger molecules, such as most bacteria and some salts, generally do not cross the placental barrier;
What substances that are harmful to the baby can pass the placental barrier?
-Viruses
-harmful drugs & other substance
The embryonic disk forms into 3 layers immediately after implantation. What are they?
- The ectoderm, or outer layer, will become the skin, the sense organs, and the brain and nervous system.
- The mesoderm, or middle layer, will become muscles, blood, and the excretory system.
- The endoderm, or inner layer, will become the digestive system, lungs, thyroid, thymus, and other organs.
will become the skin, the sense organs, and the brain and nervous system.
Ectoderm, outer layer
Will become muscles, blood, and the excretory system.
Mesoderm
Will become the digestive system, lungs, thyroid, thymus, and other organs.
Inner layer
