Embryology Flashcards
What is the ampulla?
site of fertilisation
What is the zona pellucida?
Tough protective protein layer surrounding oocyte
- Stops embryo from sticking in the fallopian tube
how does the sperm get through the zona pellucida?
acrosomal enzymes are released from the sperm head which digest the zona pellucida
What is a trophoblast?
Cells that line the zona pellucida
- Go on to form the placenta
what is the oropharyngeal membrane?
Site of future mouth
What is gastrulation?
formation of tissue (Germ) layers
What does the term morphogenesis mean?
Formation of the body plan (embryonic folding)
Whats is meant by the term induction?
The ability one cell type to cause another to differentiate
What does epigenetic mean?
Preferential expression of either the maternal or the paternal copy of a gene
On which day is implantation complete
Day 9
After gastrulation what does the ectoderm become?
- Epidermis of the skin
After gastrulation what does the endoderm become?
- Lining of the gut tube
- Lining of the respiratory tract
After gastrulation what does the mesoderm become?
Mesoderm becomes divided into 3 regions either side of the notochord
3rd month features
- Face more human looking
- Lengthening of limbs
- Ossification of long bones and skull
- Can determine Gender
4th and 5th month
Rapid increase in length
6th month –> Birth
Rapid increase in weight gain
Causes of Defects
- Infectious agent
- Radiation
- Chemical agents and prescription drugs
- Nutritional Deficiencies
- Maternal Disease
What happens during lateral folding
- Converts the open coelom into a closed cavity
- Creates thoracic and abdominal cavities and closing fore and hindgut
What happens during Cranial Folding
Forms the foregut
Defines the thoracic cavity
What happens during caudal folding
Cloacal membrane and connecting stalk are displaced ventrally alongside the neck of the yolk sac
Froms:
Hindgut
Anus
And Umbilical Cord
When does the heart begin to develop
Week 4
Name the two cardiac Septa
- Septum Primum (flexible)
2. Septum Secundum ( more rigid)
What happens during probe patent foramen ovale
- Septum prison and septum secundum fail to fuse
- mixing of blood prevented due to pressure difference
can go entire life without knowing you have this
Define Transposition of the great vessels
Aorta exits right ventricle
Pulmonary trunk exits left ventricle
Deoxygenated blood pumped around the body
THIS ARRISES DUE TO THE SPIRALLING SEPTUM - IF IT FAILS TO SPIRAL THESE PROBLEMS CAN ARISE
What are the four components of TETRALOGY OF FALLOUT
- Pulmonary Stenosis
- Hypertrophy of the left ventricle
- VSD
- Over - riding aorta
