Embryology Flashcards
On what day does hatching occur?
Day 5
On what day does implantation occur?
Day6
What prevents the cell from hypertrophy before hatching?
The Zona pellucida
Describe the structure that hatches from the Zona pellucida.
- trophoblast
- hypoblast
- Blastocoel
- Epiblast
When do the extra - embryonic tissues form?
Week 2 of embryonic development.
What are the embryonic tissues that form during week 2 of development?
- amniotic cavity,
- amnion,
- umbilical vesicle \yolk Sac,
- connecting stock
- chorion
At implantation how many germ layers are present?
1 (the embryoblast)
What is another name for the yolk sac?
exocoelomic cavity
The epiblast has a thick layer of ____ on the surface facing the _____. The hypoblast is on the surface plate facing the ____.
- columnar cells; amniotic cavity
- blastocoel
The formation of which structure marks the place where the future mouth will form? When does this happen?
Prechordal plate; day 14
What establishes the ventral - dorsal axis in the embryo?
The separation of the hypoblast and the last
What is the name for severe NVP (nausea and vomiting of pregnancy)? When does it usually subside?
- hyperemesis gravidum (<2% of pregnancies)
- week 20 (can begin at 3 weeks)
What are the main events of embryonic development during week 3?
- Appearance of primitive streak
- Development of notochord
- Gastrulation: development of trilaminar disc
What germ layers are the extra - embryonic tissues derived from?
Epiblast AND Hypoblast
(embryonic tissues only come from epiblast)
What are the structures hidden by the blue box?
What are the structures hidden by the Red Box?
What are the steps of gastrulation?
- Primitive streak develops along that the blast (with primitive node & prechordal plate at the cranial end)
- Epiblast cells migrate ventrally through the Primitive streak. Where they end up determines their germlayer (ectoderm replaces epiblast, mesoderm more ventral and endoderm most ventral)
What establishes the cranial - caudal axis?
The development of the Primitive streak along with the Primitive node at the cranial end.
(the 1st axis is the dorsal-ventral and it is formed by the separation of the hypoblast and the epiblast)
How are the left and the right side of the body developed during gastrulation?
The “Cascade of Genes”, which controls secretions present on one side and not the other.
How is the cranial end does the embryo formed?
Molecular signals from the anterior visceral endoderm.
(streak then forms caudalie under control of genes in the Primitive node region which also establishes the dorsal-ventral axis.)
