Weeks 2-8 Flashcards
What does the dorsal side of the body refer to?
The back.
What plane divides the body into right and left halves?
Median plane.
What is the function of the coronal plane?
It divides the body into anterior (ventral) and posterior (dorsal) parts.
When does the blastocyst embed into the uterine lining?
Begins at day 7.
Name the two layers of the trophoblast.
Cytotrophoblast (inner layer) and syncytiotrophoblast (outer layer).
What hormone does the syncytiotrophoblast produce?
Human chorionic gonadotrophin (hCG).
By which day is the blastocyst fully embedded in the endometrium?
By day 10.
What are primary chorionic villi?
Structures that develop on days 13–14 and are part of the placental tissues.
What marks the beginning of secondary chorionic villus development?
Mesodermal cells penetrate the core of primary villi at the start of week 3.
What are the two layers of the inner cell mass?
Hypoblast (adjacent to the blastocyst cavity) and epiblast (adjacent to the amniotic cavity).
What structure forms the floor of the amniotic cavity?
The epiblast.
What happens to the primary yolk sac during embryogenesis?
It decreases in size as the secondary yolk sac forms.
What is the role of the extraembryonic somatic mesoderm?
It lines the trophoblast and covers the amnion, forming the chorion.
When does gastrulation occur?
During the third week of development.
What germ layers are formed during gastrulation?
MEE
Mesoderm
Ectoderm
Endoderm
What does the ectoderm give rise to? REN
Retina
Epidermis
Nervous system