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55 Cards in this Set

  • Front
  • Back
Which of the 6 branchial arches is rudimentary
What 2 prominences does the 1st branchial arch split into
maxillary prominence and mandibular prominence
how many total branchial grooves are there between the arches
What is the name of the structure that is ectodermally lined and separated from the foregut by the oropharyngeal membrane
Stomodeum - also makes up ant 2/3 of oral cavity
What are the four internal evaginations of endoderm that separate each branchial arch called
Pharyngeal pouches
What is the meeting of ectoderm of branchial groove with endoderm of a pharyngeal pouch called.
Branchial Membrane
What are the three structural components of a typical branchiall arch
ectodermal outer covering(epidermis)
endodermal inner lining(mucosal)
mesenchyme core - branchiomeric mesenchyme
what four things form from the mesenchymal core of a branchial arch
blood vessel - endothelium of aortic arch
cartilaginous bar - forms from neural crest cells
muscular components - from cephalic paraxial mesoderm(somitomeres)
cranial nerve
The external acoustic canal forms from what branchial groove
1st - it forms from the ectodermal epithelium of the groove
What happens to branchial grooves 2-4 as the 1st grow down
they regress and form cervical sinus
What does the thyroid descend from
Thru foramen cecum
What is the name of the cartillage in the mandibular prominence that forms the mandible and malleus and incus
Meckels cartilage

dorsal part forms malleus and incus from endochondral ossification

ventral portion regresses to direct intramembranous formation of mandible
What things does the maxillary prominence form
maxilla, zygomatic bone and squamous portion of temporal bone by intramembranous bone formation
What is the name of the cartilage found in branchial arch 2
Reichert's cartilage
What does Reichert's cartilage form
stapes, styloid process, upper 1/2 of hyoid bone by endochondral ossificaiton
What bone does branchial arch 3 form
lower half of hyoid bone by endochondral ossification
What do branchial arches 4 and 6 form
cartilages of larynx except the epiglottis which comes from the tongue development

cricoid, thyroid
What nerve innervates the 1st, 2nd, 3rd, 4th and 6th branchial arches
V - maxillary and mandibular branches
X - superior laryngeal branch
X - recurrent vagus branch
What muscles does branchial arch 1 form
muscles of masitcation, mylohyoid, anterior belly of the digastric, tensor tympani and tensor veli palitini
What does the tensor tympani attach to
the maleus it helps dampen sounds
What muscles does the 2nd branchial arch form
muscles of facial expression, stylohyoid, post belly of digastric and stapedius
What muscle does branchial arch 3 form
What muscles do branchial arch 4 form
cricothyroid, levator veli palatini, constrictors of pharynx, palatoglossus
What muscles do branchial arch 6 form
intrinsic muscles of larynx
What does the tubotympanic recess(derived from Pharyngeal pouch 1) give rise to
middle ear cavity and pharyngotympanic canal(eustachian tube)

the first branchial membrane forms the tympanic membrane
What does pharyngeal pouch 2 give rise to
epithelium of palatine tonsil and tonsilar crypts
What is unique about the 3rd pharyngeal pouch
it evaginates to form a dorsal and ventral portion

dorsal - inferior thyroid glands
ventral - epithelial reticulus of thymus gland
What do the dorsal and ventral portions of pharyngeal pouch 4 form
dorsal - superior parathyroid glands
ventral - ultimobranchial body which is associated with neural crest cells that form c-cells("parafoliculate") of thyroid gland
What is unique about the superior and inferior parathyroid glands up until the piont that they migrate
the inferior are superior to the superior
How is the thyroid formed
it is an evagination of endoderm that develops from a diverticulum just caudal to the median tongue bud
What does the thyroid descend thru
thyroglossal duct
What are some congenital malformations of the thyroid that can occur
thyroglossal duct cyst, thyroglossal duct sinus or ectopic thyroid gland
What are some common branchial malformations
Branchial sinus, fistula or cyst
What is first arch syndrome
malformations of the ear, mandible, zygoma and palate due to insufficient migration of neural crest cells into the first arch
What is DiGeorge Syndrom
lack of parathyroid glands or thymus glands

It can lead to facial abnormalities such as low set ears and small mouth

Also can lead to defects in outflow tract of heart and great vessels
If a child has a midline swelling beneath the arch of the hyoid bone what could it be
Thyroglossal duct cyst
What can DiGeorge patients die from
they are immune compromised and can die of heart defects due to lack of heart partitioning during development
What does Rathke's pouch end up forming
ant lobe of pituitary(adenohypophisis)
What are the five facial primordia
frontonasal prominence, maxillary prominences(paired) and mandibular prominences(paired)
Where does the nasolacrimal groove form
between the lateral nasal prominence and the maxillary prominence
What does the nasolacrimal groove give rise to
nasal lacrimal duct
What are nasal placodes
they are the areas that become depressed and eventually form nasal pits(nostril holes)
What do the lateral nasal prominences form
sides of the nose(alae)
What does the medial nasal prominence form
nasal septum
How is the intermaxillary segment formed
fusion of the paired medial nasal prominences

forms the
philtrum of lip
fleshy nasal septum
premaxillary part of maxilla-holds 4 incisors
primary palate
What nerve innervates the frontonasal prominence, the maxillary prominence and mandibular prominence
V1, V2 and V3 respectively
What is the structure that separates the nasal pit from the oral cavity
oronasal membrane - it eventually ruptures and gives continuity between oral cavity and nasal cavity
When the nasal pit invaginates what does it form
nasal sac which then becomes the naris
What are the paired shelves the lift from the maxillary prominences to form the secondary palate called
lateral palatine processes
What parts make up the secondary palate
lateral palatine processes fuse with nasal septum
What is the function of the palate
separates oral and nasal cavities except in region of pharynx
Anterior cleft malformations occure what in relation to the incisive forament
anterior to it

anterior cleft malformations are malformations of the primary palate
what is the name for an anterior cleft malformation
cleft lip - results due to a incomplete fusion of maxillary prominence with the medial nasal prominence
What is a posterior cleft malformation called
cleft palate - forms due to incomplete fusion of lateral palatine processes and nasal septum
What is an oblique facial cleft
it occurs at position of nasolacrimal duct and is due to incomplete fusion of lateral and medial nasal prominences with the maxillary prominence