Embryogenesis Flashcards
Describe the embryological development of a mammalian egg to epiblast with details of the tissues that will then develop
The egg -> 16 cells
Can be divided into the inner cell mass and the trophoblast.
Inner cell mass forms the epiblast and hypoblast
The epiblast will then go on to form the endo-, ecto-, and mesoderm as well as the amniotic membrane.
The hypoblast will form Heuser’s membrane
The trophoblast will form the chorion (leads to formation of the placenta)
Describe the process of implantation
The blastocyst invades the uterine wall, where the trophoblast layer forms the chorion - an extraembryonic membrane that contributes to the placenta.
The trophoblast stimulates the development of the placenta, providing the embryo with the nutrition it requires for development.
The inner cell mass divides into two layers, the epiblast and the hypoblast.
What is gastrulation?
Formation of the three germ layers of the embryo: endo-, meso-, and ectoderm.
What does the ectoderm give rise to?
Epidermis, nervous system
What does the mesoderm give rise to?
Skeleton, muscle, dermis, kidney, blood
What does the endoderm give rise to?
Gut, liver, pancreas, lungs
What is the embryonic period in gestation?
Weeks 3-8
What is the foetal period in gestation?
Weeks 8-38
What is sex reversal syndrome
SRY on the X chromosome
What is achondroplasia
Dwarfism
What are the 5 most common pathogens to effect embryos in the first trimester
TORCH
Toxoplasma parasite Other (parvovirus) Rubella Cytomegalovirus Herpes simplex virus
What common viruses can effect babies after birth
HIV
Syphilis
Zika
What are the features of foetal alcohol syndrome
Microcephaly Short palpebral features Epicanthal folds (folds over eyelids) Low nasal bridge Short nose Flat midface Micrognathia (small jaw) Thin upper lip Smooth philtrum
What are the 4 stages of neural tube development
Induction
Elongation
Bending
Closure
