Flashcards in embryology Deck (39):
when do the pharyngeal arches develop?
weeks 4 and 5
which arch is most cranial?
how many arches are there?
5 (1,2,34,6) number 5 doesnt develop
what germ layer are the pharyngeal arches from?
all-endo, meso and ectoderm
what do the otic placodes give rise to?
which part of otic vessels gives rise to the cochlea?
which part of otic vessels gives rise to the semicircular canals?
when do the semicircular canals develop?
internal indentation ?
pouch (endoderm lining)
external indentation ?
cleft (ectoderm lining)
what are the 2 skeletalcomponents of the first arch?
maxillary process(dorasl portion)and mandibular process(ventral portion)
what muscles arise from arch 1?
muscles of mastication, mylohyoid, tensor tympani and tensor palatini (all supplied by CN V3)
skeletal components from second arch?
stapes, styloid process and stylohyoid ligament, lesser horn and upper part of body of hyoid
muscles and nerves from second arch?
muscles of facial expression, strapedius, stylohyoid.. all supplied by facial nerve
when does cochlea develop?
between week 8 and 8
what does the 3rd arch give rise to?
greater horn and lower part of body of hyoid
stylopharyngeus muscles - CN IX supply
what does the 4th and 6th arch give rise to?
muscles of 4- cricothyroid, levator palatini, pharyngeal constrictiors
muscles of 6- intrinsic layngeal
what does the 1st pouch turn into?
middle ear, eustachian tube, tympanic membrane
what does the 2nd pouch turn into?
what does the 3rd pouch turn into?
inferior parathyroid gland
what does the 4th pouch turn into?
superior parathyroid gland and C cells of thyroid
what does the 1st cleft turn into?
external auditory meatus
what does the 2nd -4thcleft turn into?
they gradullay disappear
what is microtis?
how many facial swellings are there?
when do the facial swelling develop?
from week 4
name the 5 facial swellings
maxillary prominence x2
madiubular prominence x2
how many nasal swellings are there?
name the nasal swellings?
when do the nasal swellings develop/
where does the nasolacrimal groove lie?
between maxillary prominence and lateral nasal prominance
what fuses to for the primary palate?
medial nasal prominences to give intermaxillary segement - the palatal component of this gives the primary palate
what forms the secondary palate?
what form the upper lip?
2 medial nasal prominences and 2 maxillary prominences
what forms the lower lip?
what forms the noses bridge and septum?
what forms the noses chest and tip?
what forms the alae of the nose?