Lec 31: Craniofacial Development

Question 1

What is the prominence that covers the cranial forebrain?

Answer 1

Frontonasal prominence

Question 2

What branchial arch contains the maxillary prominence and mandibular prominence?

Answer 2

Branchial arch 1 (also the largest)

Question 3

What is the embryonic structure that gives rise to the mouth and anterior oral cavity?

Answer 3

Stomodeum

Question 4

What embryonic structures give rise to the lens, inner ear, and nasal epithelium?

Answer 4

The ectodermal placodes

Question 5

What are the 5 prominences that aid in formation of the face and jaws?

Answer 5

2 Mandibular
1 frontonasal prominence
2 maxillary

Question 6

What does the mandibular prominences contribute to?

Answer 6

Lower jaw, lower lip, floor of mouth, and part of tongue

Question 7

What does the frontonasal prominence contribute to?

Answer 7

• forehead and nasal reigon

- two medial and two lateral nasal prominences

Question 8

What are the skeletal derivatives of branchial arch 1? Muscle derivatives? Motor innervation?

Answer 8

Skeletal: Maxilla, mandible, incus, malleus, zygomatic
Muscle: muscles of masication
Motor innervation: trigeminal (V)

Question 9

What are the skeletal derivatives of branchial arch 2? Muscle derivatives? Motor innervation?

Answer 9

Skeletal: Stapes, upper hyoid
Muscle: facial muscles, stapedius, posterior belly of digastric, stylohyoid
Motor innervation: facial (VII)

Question 10

What are the skeletal derivatives of branchial arch 3? Muscle derivatives? Motor innervation?

Answer 10

Skeletal: lower hyoid
Muscle: stylopharyngeus
Motor: glossopharyngeal (XI)

Question 11

What are the skeletal derivatives of branchial arches 4-6? Muscle derivatives? Motor innervation?

Answer 11

Skeletal: laryngeal cartilages
Muscle: soft palate muscles, pharyngeal and laryngeal muscles
Motor vagus (X)

Question 12

What are the two tissue types contained within each branchial arch?

Answer 12

Neural crest cells (skeletal derivatives)

Mesoderm (muscle derivatives)

Question 13

What is the fate of pharyngeal pouch 1?

Answer 13

tympanic cavity and auditory tube, tympanic membrane (in conjunction with 1st arch)

Question 14

What is the fate of pharyngeal pouch 2?

Answer 14

palatine tonsils

Question 15

What is the fate of pharyngeal pouch 3?

Answer 15

thymus and inferior parathyroids

Question 16

What is the fate of pharyngeal pouch 4?

Answer 16

Superior parathyroids (migrate ventrally)

Question 17

What is the fate of pharyngeal pouch 5 (postbranchial body)?

Answer 17

associated with crest-derived C-cells of thyroid

Question 18

What is the fate of the ventral midline diverticulum?

Answer 18

thymus (migrates ventrally)

Question 19

What is the source of Shh, what is its role, and what disease do disruptions in it cause?

Answer 19

Source is notochord and prechordal mesoderm, as well as facial ectoderm and foregut endoderm
Role is in forebrain induction and crest development
Related to holoprosencephaly and possible Down Syndrome

Question 20

What is the source of RA, what is its role, and what disease do disruptions in it cause?

Answer 20

Source is paraaxial and lateral mesoderm
Role is in Hox programming and crest development
Related to Fetal Retinoid syndrome

Question 21

What is the role of TCOF1, and what disease is is related to if disrupted?

Answer 21

Role is in 1st and 2nd branchial arch development

Related to Treacher Collins

Question 22

What is the source of Tbx1, its role, and its related disorder?

Answer 22

Source is pharyngeal endoderm and mesoderm
Role is in crest and 3-4th pouch development
Related to 22q11 deletions (DiGeorge syndrome)

Question 23

How does a unilateral cleft upper lip result?

Answer 23

Failure to fuse of medial nasal and maxillary prominences

Question 24

How does an anterior cleft palate result?

Answer 24

Failure to fuse of medial palatine process with lateral palatine shelf

Question 25

How does a posterior cleft palate result?

Answer 25

Failure to fuse of two lateral palatine shelves