Embryology Flashcards
What does the neck develop from ?
Brachial and Pharyngeal arches
What does the face develop from ?
5 Mesenchymal processes
What does the skull develop from ?
Mesenchyme in the head region of the developing embryo
What is mesenchyme ?
An embryological connective tissue
What leads to axis formation in the developing embryo ?
Notochord
Does the notochord run the full length of the embryo ?
No it does not
What structures form either end of the notochord ?
Future mouth and anus
Is there any mesoderm at the future sites of the mouth and anus ?
No the endoderm is in contact with the ectoderm
How does the neural tube form ?
The notochord causes the ectoderm to thicken and form the neural tube
Where do neural crest cells come from ?
The crest regions of the neural folds
What are somites derived from ?
The paraxial mesoderm
How many somites are there in total ?
33
How many brachial arches form in humans ?
5
What is found in each arch ?
An artery, nerve and skeletal element
What forms the muscle and cartilages of each arch ?
Mesoderm and neural crest cells
Which nerves supply each brachial arch ?
Arch 1 - Trigeminal V3
Arch 2 - Facial
Arch 3 - Glossopharyngeal
Arch 4 - Superior laryngeal branch of vagus
Arch 6 - Recurrent laryngeal branch of vagus
What are the names of the 5 processes that form the face ?
1 Fronto-nasal
2 Maxillary
2 Mandibular
How do the nostrils form ?
The lateral nasal processes thicken to form the nasal placode. This then invaginates to form the nostril.
What forms the philtrum ?
The medial nasal process grows downwards and laterally to form the philtrum.
How is the palate formed ?
The medial nasal process forms the primary palate, the maxillary process forms 2 shelves which fuse with the nasal process to form the secondary palate.
Which congenital abnormality is seen alongside a cleft lip ?
A cleft palate
What type of bone formation does the cranial vault form from ?
Intramembranous ossification
What does the viscerocranium form from ? (2)
Special sense capsules and brachial arches
What type of bone formation does the base of the skull form from ?
Endochondral ossification
