Embryology Flashcards
How does the pancreas develop within the mesentery?
Tail in dorsal mesentery
Head in ventral mesentery
When does lateral folding of the embryo occur during development?
Days 18-24
What name is given to the identical ball of cells formed before the blastocyst?
Morula
What are the 2 cell layers in a blastocyst?
Trophoblast and Embryoblast
When does implantation occur?
Day 6
When does the amniotic cavity form?
Day 8
What is the Syncitiotrophoblast?
Multinucleated cell, multiple cells fused together, surrounds embryo
Secretes enzymes to aid invasion of the endometrium by the forming embryo
When does the primary yolk sac form?
Day 9
What does the extraembryonic mesoderm consist of?
Cells, extracellular matrix, cavities (coelom)
What is formed by cavitation of extraembryonic mesoderm?
Chorionic cavity, fluid filled
At day 13, what structure is present which will form the future umbilicus?
Connecting stalk, made from extraembryonic mesoderm
At day 13, what cell laters form the bilayer disc?
Epiblast and hypoblast
When is the first time to notice that the menstrual period is late?
Day 15
What are the primitive streak and node?
Raised areas of ectoderm, significant cell division
Streak extends from cloaca to primitive node
What are primitive groove and pit?
Indentations of ectoderm in centre of streak and node
At day 15, what primitive forms of the mouth and anus are present?
Prochordal plate - mouth
Cloacal membrane - anus
What is Gastrulation?
Formation of 3 germ cell layers
Migration of epiblast cells from primitive streak towards hypoblast
During Gastrulation, which parts of the embryonic disc remain mesoderm free?
Buccopharyngeal and cloacal membranes
What does ectoderm develop into?
Skin and neural tissue
What does endoderm develop into?
Lining of gut tube, respiratory system and urinary system
What does mesoderm develop into?
Paraxial - somite (skeleton, muscle, dermis of skin)
Intermediate - genitourinary
Lateral plate - serous membranes
Muscle, bone, connective tissue, organs, body cavity linings (peritoneum)