Head & Neck embryology Flashcards
what is the neck formed from?
pharyngeal/branchial arches
what are the brnachiall arches?
series of arches which develop around the future mouth and pharynx
how many branchial arches develop in humans?
5 develop ( 6 start to form but arch no.5 dissappears)
what embryological tissues make up the branchial arches?
ectoderm - outside
mesoderm - middle (+neural crest cells)
endoderm - inside
what do endoderm pouches form?
tongue
pituitary gland
what is the relationship between branchial arches and nerves?
each branchial arch corresponds to a specific cranial nerve?
what nerve is associated with the 1st arch?
mandibular branch of trigeminal nerve
what nerve is associated with the 2nd arch?
facial nerve
what nerve is associated with the 3rd arch?
glossopharyngeal nerve
what nerve is associated with the 4th arch?
superior laryngeal branch of vagus
what nerve is associated with the 6th arch?
recurrent laryngeal branch of vagus
where do the muscles of the face form from?
2nd branchial arch
which branchial arch does the digastric muscle form from?
1st
what can be deduced from a muscles nerve supply?
which branchial arch it is derived from
what is the upper part of the hyoid bone formed from?
the 2nd branchial arch
what important structures develop from the branchial arches (excluding nerves)
tongue
thyroid gland
parathyroid gland
part of the pituitary gland
what are the 5 processes/prominences that form the face?
frontonasal process
maxillary processes x 2
mandibular processes x 2
what are the maxillary and mandibular processes formed from?
1st branchial arch mesoderm
what is the nasal placode?
thickening of the ectoderm of the frontonasal process
what is the philtrum?
a downward and lateral growth of the medial nasal process
wht is the first stage of palate development?
medial nasal process grows downwards and forms philtrum, this forms the primary palate
what is the second stage of of palate development?
two palatine shelves grow inwards from the maxillary processes
what is the third stage of palate development?
palatine shelves meet in the midline to form the secondary palate
what is the purpose of the palate?
to separate the oral and nasal cavities
how is the cranial vault formed
membranous ossification
what kind of bones are the cranial vault
flat bones
what kind of bones form the base of the skull
irregular bones
what is the viscerocranium?
skeleton of face
how is the base of the skull formed
endochondral ossification
what is craniosynostosis?
premature fusion of skull bones
what is the mesenchyme around the notochord primarily formed from?
neural crest cells
what is mesenchyme?
embryonic connective tissue
what are somites derived from?
paraxial mesoderm
what do somites form?
axial skeleton and muscles
