Pharyngeal Arches (Exam 3) Flashcards
When will the pharyngeal apparatus develop
4th week of development
Where does the pharyngeal apparatus develop
cephalic region of the ebryo
What is the pharyngeal apparatus also called
branchial arch
What are the different parts of the pharyngeal apparatus
pharyngeal arch
pharyngeal pouch
pharyngeal groove
pharyngeal membrane
What type of tissue will line the pharyngeal cleft/groove and pouch
pouches lined with endoderm
clefts lined with ectoderm
What separates each pharyngeal arch
pharyngeal membrane
What is contained within a typical pharyngeal arch
aortic arch segment
cartilaginous piece
nerve
mesenchymal tissue
What will the mesenchymal tissue in the pharyngeal arches become
musculature of the arch
What are the two prominences formed by the first pharyngeal arch
mandibular and maxillary prominences
Where is the oropharyngeal membrane seen
between the two parts of the first arch; membrane
What occurs to the oropharyngeal membrane and what does it become
ruptures and produces and opening form the pharynx to the amniotic cavity
What are the layers of the oropharyngeal membrane
outer ectoderm layer
inner endoderm layer
What nerve is associated with the first arch
CN V: Trigeminus
What muscles are associated with the first arch
anterior belly digastric mylohyoid tensor tympani tensor veli palatini muscles of mastication
What nerve is associated with the second arch
CN VII: Facial Nerve
What muscles are associated with the second arch
posterior belly digastric
stylohyloid
stapedius
muscles of facial expression
What nerve is associated with the third arch
CN IX: glossopharyngeal
What muscles are associated with the third arch
stylopharyngeus
What are the branches of trigeminal
V1: ophthalmic
V2: maxillary
V3: Mandibular
What branches of trigeminal are motor
V3, mandibular
What branches of trigeminal are sensory
V1 opthalmic
V2 maxillary
What nerve is associated with the 4th and 6th arches
CN X: vagus
What muscles are associated with the 4th and 6th arches
pharyngeal constrictors laryngeal muscles cricothyroid (4th) levator veli palatini skeletal muscle of the esophagus
Muscles with tensor in their name are innervated by what
V3
Muscles with palato in their name are innervated by what nerve
CN X
Muscles with glossus in their name are innervated by what
CN XII
What are the cranial nerves with parasympathetic component
3,7,9,10
What are s/s of Treacher collins syndrome
misshapen ears
eyes are drooping
mandibular hypoplasia
facial abnormalities
What causes Treacher collins syndrome
first arch fails
neural crest cells fail to migrate properly and affects the cartilage and muscles coming form the 1st arch
What is Pierre Robin Sequence cause by
Improper formation of the first arch
What are the S/S of Pierre Robin Sequence
glossoptosis
micrognathia/retrognathia
cleft palate
What is glossoptosis
posteriorly placed tongue that can obstruct airway
What is micrognathia/retrognathia
posterior placed jaw
What is cleft palate
tongue doesn’t drop out of the way for the two shelves of the palate to come together
What will the 1st pharyngeal pouch become
eustachian tube; tympanic membrane
What will the 2nd pharyngeal pouch become
tonsillar fossa: palatine tonsil
What will the 3rd pharyngeal pouch become
Dorsal: inferior parathyroid glands
Ventral: primordial thyroid
What will the 4th pharyngeal pouch become
Dorsal: superior pair of parathyroid glands
Ventral: ultamopharyngeal body
What is the ultamopharyngeal body
part of the thyroid that will become C cells to produce calcitonin
Where do the superior parathyroid gland sit
on the back of the thyroid gland
What will the 1st pharyngeal groove/cleft become
external auditory tube
What will the sandwhich between the cleft and pouch become
tympanic membrane
How many layers compose the tympanic membrane
3
What are possible clinical correlations to the 2nd pharyngeal groove/cleft
cervical cysts and fistulas
What causes cervical cysts and fistulas to occur
if arch 2 doesn’t come all the way down over the 3rd and 4th arches
What is a branchial fistula
improper closing of the 2nd pharyngeal groove creates a cyst, fistula is connection to external environment
What is an ectopic thyroid
thyroid tissue at the base of the tongue
When is an ectopic thyroid often symptomatic
during puberty
What are CT findings of an ectopic thyroid
midline, at the tongue base
attenuation and enhancement=similar to thyroid tissue
absent thyroid tissue in the expected normal location
What is a pharyngeal membrane
where pouch and groove meet
When do the salivary glands develop
7th week
What is the development process for salivary glands
from solid cords growing from the oral cavity
cords grow into the surrounding mesenchyme
What composes the stroma of the salivary glands
NCC
What composes the parenchyma of the salivary glands
oral epithelium
What is the cartilage derivative of the first arch
known as Meckel’s cartilage
maleus, incus, mandible, anterior ligament of malleus, sphenomandibular libament
What is the cartilage derivative of the second arch
stapes, styloid, stylohyoid lig, lesser horn and superior part of hyoid
What is the cartilage derivative of the third arch
greater horn and inferior part of hyoid
What is the cartilage derivative of the 4th arch
laryngeal cartilages
What will the 5th pharyngeal pouch become
largely regresses and helps to form the ultimopharyngeal body
When does the thyroid gland begin to form
day 24
The thyroid gland is the first what
endocrine gland to form
What is the thyroglossal duct
connection between the tongue and thyroid in embryo
The thyrogloassal duct remains open as what
foramen cecum
How is the pyramidal lobe of the thyroid gland formed
from the thyroglossal duct
What are branchial vestiges
pharyngeal cartilages that did not normally disappear; remnant of cartilage or bony elements under the skin anterior to the inferior 1/3 of the SCM persist
What is DiGeorge anomaly
abnormalities of the heart, parathyroid gland, face, thymus gland. Affected individuals will have congenital heart disease, unusual facial features with low-set ears, a small receding mandible, wide-set eyes and are born without parathyroid glands
What is Goldehar Syndrome caused by
abnormal development of the 1st and 2nd pharyngeal arches
When will the medial and tongue buds be seen
5th week
What forms the median tongue buds
elevation appears on the floor of the pharynx just rostral to the foramen cecum (endoderm)
What forms the anterior 2/3 of the tongue
fused distal tongue buds
What does the median tongue bud contribute to the tongue
nothing notable
WHat forms the posterior 1/3 of the tongue
growth behind the foramen cecum and hypopharyngeal eminence
What marks the division between the anterior 2/3 and posterior 1/3 of the tongue
terminal sulcus
What are most of the tongue muscles derived from
occipital somites
What nerve is associated with muscles of the tongue
hypoglossal nerve
What is the somatic and visceral sensation for the anterior 2/3 of the tongue
somatic CN V
Visceral CN VII
What nerve will supply the sensory innervation to the posterior 1/3 of the tongue
CN IX
What role does the vagus have involving the tongue
supplies the palatoglossus and carries taste from the root of the tongue
Where will taste buds form
dorsal tongue palatoglossal arches palate epiglottis posterior wall of pharynx
What are congenital cysts in the tongue
remnant of the thyroglossal duct
What is ankyloglossia
tongue tie
What is tongue tie
abnormally short frenulum that anchors the tongue to the floor of the oral cavity
What is Macroglossia
unusually large tongue
What is microglossia
unusually small tongue
What is bifid tongue (glossoschisis)
tongue split in 2
