pharyngeal apparatus

Question 1

pharyngeal apparatus

Answer 1

pharyngeal clefts
pharyngeal arches
pharyngeal pouches

Question 2

pharyngeal clefts

Answer 2

external invagination of ectoderm

4

Question 3

pharyngeal arches

Answer 3

core of mesenchyme (neural crest and paraxial mesoderm)
neural crest gives rise to CT components, paraxial mesoderm to mm
each arch own CN and blood supply
6 arches, by 5th regresses

Question 4

pharyngeal pouches

Answer 4

internal evagination of pharyngeal endoderm

4

Question 5

arch 1 skeletal derivatives

Answer 5

viscerocramium (malleus, incus)

CT of face

Question 6

arch 1 mm derivatives

Answer 6

mm of mastication
ant belly of diagastric 
mylohyoid
tensor tympani
tensor veli palatini

Question 7

Nerve of arch 1

Answer 7

V3

Question 8

Oropharyngeal membrane

Answer 8

from 2 processes of arch 1
outer layer of ectoderm and inner layer of endoderm
ruptures by day 26 to allow for communication btwn oral cavity and pharynx

Question 9

arch 2 skeletal derivatives

Answer 9

stapes, styloid process of temporal bone

stylohyoid lig, lesser horn and sup portion of body of hyoid

Question 10

arch 2 mm derivatives

Answer 10

mm of facial expression
stylohyoid
posterior belly of diagastric
stapedius

Question 11

nerve of arch 2

Answer 11

VII

Question 12

arch 3 skeletal derivatives

Answer 12

greater horn and inferior portion of body of hyoid bone

Question 13

arch 3 mm derivatives

Answer 13

stylopharyngeus

Question 14

n of arch 3

Answer 14

glossopharygeal IX

Question 15

arch 4 skeletal derivatives

Answer 15

forms all laryngeal cartilages

Question 16

arch 4 of mm derivatives

Answer 16

cricothyroid

Question 17

arch 4 n

Answer 17

X

Question 18

arch 6 skeletal derivatives

Answer 18

w/4th arch form all laryngeal cartilages

Question 19

arch 6 mm derivatives

Answer 19

laryngeal mm except cricothyroid

skeletal m of esophagus

Question 20

nerve of arch 6

Answer 20

X and recurrent laryngeal n

Question 21

pouch 1

Answer 21

contributes to formation of middle ear and auditory tube

Question 22

pouch 2

Answer 22

forms stroma of palatine tonsil

tonsillar fossa

Question 23

pouch 3

Answer 23

dorsal portion- inf parathyroid glands

ventral portion- thymus

Question 24

pouch 4

Answer 24

dorsal portion- sup parathyroid glands

ventral portion- ultimobrachial body

Question 25

first cleft

Answer 25

formation of external ear

Question 26

clefts 2-4

Answer 26

get buried by arch 2

remnants form cervical sinus which is later obliterated

Question 27

thyroid development

Answer 27

derived froom median endodernal thickening of pharyngeal floor
connected to tongue by thyroglossal duct until wk 7
superior opening of thyroglossal duct becomes foramen cecum
50% of ppl of pyramidal lobe, remnant of distal thyroglossal duct
parafollicular C cells derived froom ultimobrachial body of 4th pouch

Question 28

tongue development

Answer 28

1st pharyngeal arch form the body (ant 2/3) GSA from V
3rd arch forms root (post 1/3) GVA from glossopharyngeal
4th arch forms epiglottic region of tongue GVA from X
mm derived from paraxial mesoderm of occiptial somites

Question 29

lateral cervical cysts

Answer 29

form when cervical sinus fails to degenerate

found along ant border of SCM

Question 30

Branchial fistulas

Answer 30

when 2nd arch fails to overgrow 3rd and 4th arches
cervical sinus retains connection w/surface (external fistula)
rarely the lateral cervical cyst can open into pharynx (internal fistula)

Question 31

neural crest defects

Answer 31

treacher collins syndrome
robin sequence
DiGeorge anomaly

Question 32

DiGeorge syndrome

Answer 32

deletion of long arm chrom 22
cardiac abnormalities
craniofacial defects
thymic hypoplasia
parathyroid dysfunction -> hypocalcemic