Embryology Flashcards
The Embryoblast splits into which two layers?
Epiblast
Hypoblast
What does a blastocyst consist of?
Embryoblast
Trophoblast
What does the trophoblast split into? And at what stage does this happen?
Cytotrophoblast
Syncytiotrophoblast
In week to when in invades the endometrium
What are the two cavities formed in week 2?
Yolk sac
Amniotic cavity
What happens to the syncytiotrophoblast in week 2?
It becomes vascularised in maternal blood
At what stage is the embryo known as en bilaminar embryonic disc?
Week 2
Where does the primitive streak form from and in which week?
Week three from the Epiblast
What is gastrulation? When does this occur?
Week three
It’s the formation of the three germ layers from the Epiblast
What are the three layers that the Epiblast forms?
Endoderm
Mesoderm
Ectoderm
Where does the notochord form from and when?
Week 3 from the mesoderm
What is derived from the ectoderm?
Epidermis of skin
Brain, spinal cord, peripheral nerves and nervous tissue
What is derived from the mesoderm?
Skeleton Connective tissue Cartilage Muscle, tendons and ligaments Vessels and blood Urogenital system
What is derived from the endoderm?
Epithelial of organ systems
Glands
Digestive organs
What cells are in the primitive node?
Notochord cells
What are the three main steps of gastrulation?
First, cells proliferate and begin to migrate and displace the hypoblast layer, this forms the endoderm
Secondly, cells migrate and settle above endoderm to form the mesoderm
Remaining Epiblast cells form the ectoderm
What is neurulation and when does it happen?
Transformation of neural plate into neural tube week 3 + 4
What is the notochord?
A column of midline cells vital for induction of neural plate, motor region of the brain and spinal cord and vertebral formation.
At the end of week four when neural tube closure is complete, what are the 3 primary brain vesicles that are formed?
Forebrain
Midbrain
Hindbrain