Pharyngeal Arches

Question 1

most congenital anomalies in head and neck originate during transformation of the pharyngeal apparatus into its adult derivatives

Answer 1

pharyngeal arches

Question 2

pharyngeal arches develop in the _____ (#) week as ____________ that migrate into the future head and neck regions

Answer 2

4th week, neural crest cells

Question 3

Appear as surface elevations to the developing pharynx

Answer 3

primordium of the jaws (the first pair of pharyngeal arches)

Question 4

by the end of the 4th week, how many well-defined pairs of pharyngeal arches are visible externally

Answer 4

four

Question 5

rudimentary and not visible on the surface of the embryo

Answer 5

5th and 6th arches

Question 6

arches are separated from each other by prominent fissures called

Answer 6

pharyngeal grooves (clefts)

Question 7

the first pharyngeal arch (mandibular arch) develops into two prominences:

Answer 7

maxillary and mandibular prominences

Question 8

gives rise to the maxilla, zygomatic bone, ad squamous part of the temporal bone

Answer 8

maxillary prominence of the first pharyngeal arch

Question 9

forms the mandible

Answer 9

mandibular prominence of the 1st pharyngeal arch

Question 10

makes a major contribution to the formation of the hyoid bone

Answer 10

second pharyngeal arch (hyoid arch)

Question 11

appears as a slight depression of the surface ectoderm, its separated by the oropharyngeal membrane

Answer 11

stomodeum (primordial mouth)

Question 12

the stomodeum is separated from the cavity of the primordial pharynx by a bilaminar membrane

Answer 12

oropharyngeal membrane

Question 13

ruptures at 26 days, bringing the primordial pharynx and foregut into communication with the external environment

Answer 13

oropharyngeal membrane

Question 14

Initially, each pharyngeal arch consists of a core of ________ and is covered externally by _______ and internally by ________

Answer 14

mesenchyme (embryonic CT), ectoderm, endoderm

Question 15

the original mesenchyme is derived from mesoderm in what week

Answer 15

third week

Question 16

during the 4th week, most of the mesenchyme is derived from __________ that migrate into the pharyngeal arches

Answer 16

neural crest cells

Question 17

a typical pharyngeal arch contains:

Answer 17

aortic arch, cartilaginous rod, muscular component, and a nerve

Question 18

an artery that arise from the truncus arteriosus of the primordial heart

Answer 18

aortic arch

Question 19

forms the skeleton of the arch

Answer 19

cartilaginous rod

Question 20

forms muscles in the head and neck

Answer 20

muscular component of pharyngeal arches

Question 21

supplies the mucosa and muscles derived from the arch

Answer 21

nerve of pharyngeal arches

Question 22

nerve deriving from the first arch (mandibular)

Answer 22

mandibular nerve/ V3 of trigeminal nerve (CN V)

Question 23

muscles of the first arch (mandibular)

Answer 23

muscles of mastication, myohyoid and ant. belly of digastric, tensor tympani, and tensor veli palatini

Question 24

skeletal structure of first arch

Answer 24

malleus and incus

Question 25

ligaments deriving from the first arch (mandibular)

Answer 25

anterior ligament of malleus and sphenomandibular ligament

Question 26

nerve deriving from the second arch (hyoid)

Answer 26

fascial nerve (CN VII)

Question 27

muscles deriving from the second arch (hyoid)

Answer 27

muscles of fascial expressions, stapedius m., stylohyoid m., post. belly of digastric

Question 28

skeletal structures deriving from the second arch (hyoid)

Answer 28

stapes, styloid process, lesser horn and upper part of body of hyoid bone

Question 29

ligaments deriving from second arch (hyoid)

Answer 29

stylohyoid ligament

Question 30

nerve deriving from the 3rd arch

Answer 30

glossopharyngeal (CN IX)

Question 31

muscles deriving from the 3rd arch

Answer 31

stylopharyngeus

Question 32

skeletal structure from 3rd arch

Answer 32

greater horn and lower part of body of hyoid bone

Question 33

nerve deriving from 4th arch

Answer 33

superior laryngeal branch of VAGUS (CN X)

Question 34

muscles deriving from 4th arch

Answer 34

cricothyroid and levator veli palatini

Question 35

skeletal structures deriving from 4th arch

Answer 35

thyroid cartilage and cricoid cartilage

Question 36

nerve deriving from 6th arch

Answer 36

recurrent laryngeal branch of VAGUSs (CN X)

Question 37

muscles of the 6th arch

Answer 37

constrictors of pharynx, intrinsic muscles of larynx, striated muscles of esophagus

Question 38

skeletal structures derived from the 6th arch

Answer 38

arytenoid cartilage, corniculate cartilage, and cuneiform cartilage

Question 39

during the 5th week, the 2nd pharyngeal arch enlarges and overgrows the 3rd and 4th arches, forming an ectodermal depression called

Answer 39

the cervical sinus