Craniofacial development

Question 1

Each Pharyngeal arch has

Answer 1

Muscle
Cartilaginous rod- initiates formation of skeletal elements
Cranial nerve
Aortic arch artery

Question 2

Mesenchymal core

Answer 2

Mesoderm- giver rise to musculature

Neuro crest cells- migrate into the pharyngeal arches to contribute to cartilage/bone and connective tissue

Question 3

derived mainly from arches 1&2

Answer 3

Face

Question 4

Derived from arches 3&4

Answer 4

Neck components

Question 5

Arch 1

Answer 5

Muscle- mastication
meckel's cartilage
malleus and incus
mandible
CN V3

Question 6

Arch 2

Answer 6

muscle- facial expression
reichert's cartilage
stapes and temporal bone styloid process
hyoid bone
CN VII

Question 7

Arch 3

Answer 7

Muscle- stylopharyngeus
hyoid
CN IX

Question 8

Arch 4&6

Answer 8

muscle- pharynx constrictors
laryngeal cartilages
CNX and recurrent fibers

Question 9

Symptoms results from defects in growth of the 1st and 2nd pharyngeal arches
leads to - dysplasia/hypoplasia/aplasia of the musculoskeletal derivatives of these arches

Answer 9

Treacher collins syndrom

mutation in TCOF1 gene

Question 10

Malformation of 1st arch structures- mandible most severely affected
difficulties breathing and eating

Answer 10

Pierre Robin sequence

Triad- micrognathia/cleft palate/glossoptosis(posteriorly placed tongue)

Question 11

The only cleft that contributes to the definitive structure of the embryo

Answer 11

Dorsal region of the 1st cleft- gives rise to the external auditory meatus

Question 12

Cervical sinus cavity

Answer 12

occurs from proliferation of the 2nd arch causing it to overlap with the 3rd and 4th

Question 13

Results when the 2nd arch fails to completely cover the 3rd and 4th

Answer 13

Crachial fistula

Question 14

forms tympanic cavity and auditory tube

Answer 14

1st pouch

Question 15

forms palatine tonsils

Answer 15

2nd pouch

Question 16

forms interior parathyroid gland and thymus

Answer 16

3rd pouch

Question 17

forms superior parathyroid gland and ultimo brachial body

Answer 17

4th pouch- source of C cells for thyroid

Question 18

Ectopic thyroid gland

Answer 18

Thyroglossal cyst- often impinge on the lumen of the pharynx and impede swallowing

Question 19

Development of the tongue

Answer 19

develops from the ventral surface of all four pharyngeal arches

Question 20

forms the anterior 2/3rds of the tongue

Answer 20

tuberculum impar- appear on the ventral surface of the 1st arch

Question 21

forms the posterior 1/3rd and root of the tongue

Answer 21

Hypopharyngeal eminence

-derived from the 2nd/3rd/4th arches

Question 22

Results when the tongue is not completely freed from the floor of the mouth

Answer 22

Ankylogossia

Question 23

Forms the anterior portion of the hard palate

Answer 23

Primary palate

Question 24

Forms via fusion of palatine shelves to give rise to the posterior hard palate and soft palate

Answer 24

Secondary palate

Question 25

Nasolacrimal groove

Answer 25

invaginates to form

• nasolacrimal duct
• lacrimal sac

Question 26

Results from failed fusion of the maxillary and medial nasal prominences

Answer 26

Cleft lip

Question 27

Results from failure of palatine shovels to fuse with one another and/or the primary palate

Answer 27

Cleft palate

Question 28

Palatine shelves failing to fuse with the primary palate

Answer 28

Anterior/primary palate

Question 29

Failure of the palatine shelves to fuse with each other and with the nasal septum

Answer 29

Posterior/secondary palate

Question 30

Ondotoblasts

Answer 30

produce dentin

Question 31

Ameloblasts

Answer 31

Produce enamel

Question 32

Results from defects in enamel secretion or mineralization

Answer 32

Amelogenesis imperfecta

Vit A deficiency or measles can cause enamel defects