development of pharyngeal arches

Question 1

pharyngeal arches consist of a core of mesenchyme which is made of ____

Answer 1

mesoderm and NCCs

Question 2

pharyngeal arches are covered by ____ externally and ____ internally

Answer 2

ectoderm
endoderm

Question 3

pharyngeal arches are separated by ____ externally and ____ internally

Answer 3

pharyngeal clefts/grooves
pharyngeal pouches

Question 4

where groove and pouch touch

Answer 4

pharyngeal membrane

Question 5

what is crucial for proper facial development?

Answer 5

1st arch separates found on either side of oropharyngeal membrane

Question 6

allows future pharynx and foregut to communicate with amniotic cavity once oropharyngeal membrane breaks down

Answer 6

stomodeum

Question 7

components of pharyngeal arches

Answer 7

artery
cartilaginous rod
muscular component
nerve

Question 8

from truncus arteriosus of heart

Answer 8

artery

Question 9

supports the arch and is involved in formation of arch derived skeletal elements

Answer 9

cartilaginous rod

Question 10

forms many muscles of head and neck

Answer 10

muscular component

Question 11

each arch is associated with one ____ that supplies skin, mucosa, and muscles associated with the arch

Answer 11

cranial nerve

Question 12

arches contributions

Answer 12

face
nasal cavities
mouth
larynx
pharynx
neck

Question 13

1st arch cartilage derivatives

Answer 13

palatoquadrate bar (maxillary swelling): incus and alisphenoid
Meckel’s cartilage (mandibular swelling): proximal: malleus, anterior ligament of malleus and sphenomandibular ligament
distal: mandible

Question 14

2nd arch cartilage derivatives

Answer 14

reichert’s cartilage: stapes, styloid process, stylohyoid ligament, lesser cornua and body of hyoid bone

Question 15

3rd arch cartilage derivatives

Answer 15

greater cornua and part of body of hyoid bone

Question 16

4th and 6th arch cartilage derivatives

Answer 16

laryngeal cartilages

Question 17

1st arch artery derivative

Answer 17

maxillary artery

Question 18

2nd arch artery derivative

Answer 18

stapedial artery

Question 19

3rd arch artery derivative

Answer 19

common carotid artery and proximal internal carotid artery

Question 20

4th arch artery derivative

Answer 20

R: proximal right subclavian artery
L: arch of aorta

Question 21

6th arch artery derivative

Answer 21

L: proximal left pulmonary artery and ductus arteriosus
R: proximal right pulmonary artery

Question 22

1st arch muscle derivatives

Answer 22

muscles of mastication: temporalis, pterygoids and masseter
tensor tympani
tensor veli palatini
mylohyoid
anterior belly of digastric

Question 23

2nd arch muscle derivatives

Answer 23

muscles of facial expression
posterior belly of digastric
stylohyoid
stapedius

Question 24

3rd arch muscle derivative

Answer 24

stylopharyngeus

Question 25

4th and 6th arch muscles derivatives

Answer 25

pharyngeal constrictors levator palatini cricothyroid laryngeal muscles

Question 26

1st arch nerve

Answer 26

trigeminal CN V

Question 27

2nd arch nerve

Answer 27

facial CN VII

Question 28

3rd arch nerve

Answer 28

glossopharyngeal CN IX

Question 29

4th and 6th arch nerve

Answer 29

vagus CN X

Question 30

1st pharyngeal cleft derivative

Answer 30

external acoustic meatus external layer of tympanic membrane

Question 31

how is the cervical sinus created?

Answer 31

remaining grooves are obliterated by overgrowth of 2nd pharyngeal groove

Question 32

1st pharyngeal pouch derivatives

Answer 32

tubotympanic recess tympanic cavity mastoid antrum internal surface of tympanic membrane pharyngotympanic tube

Question 33

2nd pharyngeal pouch derivatives

Answer 33

tonsillar sinus (fossa) tonsillar crypts

Question 34

3rd pharyngeal pouch derivatives

Answer 34

dorsal: inferior parathyroid gland ventral: thymus

Question 35

4th pharyngeal pouch derivatives

Answer 35

superior parathyroid gland ultimobranchial body

Question 36

describe the development of the tongue

Answer 36

begins as median swelling on floor of primordial pharynx rostral to foramen cecum two distal tongue buds rapidly increase in size, fuse and overgrow median tongue bud creating anterior 2/3 tongue copula from fusion of ventromedial parts of 2nd arches forms caudal to foramen cecum hypopharyngeal eminence from ventromedial parts of 3rd and 4th arches overgrows copula forming posterior 1/3 of tongue

Question 37

where are most of the tongue muscles derived from?

Answer 37

occipital somites

Question 38

firs endocrine gland to develop

Answer 38

thyroid

Question 39

describe the development of the thyroid

Answer 39

forms from median endodermal thickening of floor of primordial pharynx becomes an out-pocketing (thyroid primordium)

Question 40

where is the orientation of the thyroid when it descends into the neck?

Answer 40

ventral to hyoid and laryngeal cartilages

Question 41

proximal opening of thyroglossal duct persists as small pit

Answer 41

foramen cecum

Question 42

thyroid gland is connected to tongue via ____

Answer 42

thyroglossal duct

Question 43

form anywhere along the course of the thyroglossal duct

Answer 43

thyroglossal duct cyst

Question 44

where can a thyroglossal cyst form?

Answer 44

in tongue or anterior to neck just inferior to hyoid bone

Question 45

opens in median plane anterior to laryngeal cartilages

Answer 45

thyroglossal duct sinus